WO2011160053A2

WO2011160053A2 - Melt stable polyesters

Info

Publication number: WO2011160053A2
Application number: PCT/US2011/040934
Authority: WO
Inventors: Yelena Kann; Joseph Huang; Xiudong Sun; Robert S. Whitehouse
Original assignee: Metabolix, Inc.
Priority date: 2010-06-18
Filing date: 2011-06-17
Publication date: 2011-12-22
Also published as: WO2011160053A3

Abstract

Compositions comprising melt stable polyesters and chain extenders are described.

Description

MELT STABLE POLYESTERS

RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 61/356,313 entitled "Melt Stable Polyesters," filed on June 18, 2010, and U.S. Provisional Application No. 61/368,201, filed July 27, 2010, the entire teachings of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] Biodegradable plastics are of increasing industrial interest as replacements or supplements for non-biodegradable plastics in a wide range of applications and in particular for packaging applications. One class of biodegradable polymers is the polyhydroxyalkanoates (PHAs), which are linear, aliphatic polyesters that can be produced by numerous microorganisms for use as intracellular storage material. Articles made from the polymers are generally recognized by soil microbes as a food source. There has therefore been a great deal of interest in the commercial development of these polymers, particularly for disposable consumer items. The polymers exhibit good biodegradability and useful physical properties.

[0003] PHA polymers have quite limited thermal stability, and undergo chain scission by beta-elimination mechanisms at general processing temperatures and conditions. This can reduce the molecular weight quite significantly which is undesirable for certain applications. Hydrolysis of PHA can be a problem in high humidity and high temperature applications due to the generation of carboxylic acid end groups from random hydrolytic chain scission that further catalyzes decomposition of the PHA. Commercial utility of PHAs also can be limited in some applications, such as films, coatings and thermoforming, because of the low melt strength or melt elasticity often found in linear polymers. Thus, a need exists to address these shortcomings.

SUMMARY OF THE INVENTION

[0004] In accordance with an embodiment of the invention, a composition comprising a biobased polyhydroxyalkanoate polymer (PHA) and a chain extender is provided. The compositions of the invention display many unexpected synergies in melt rheology, processing

1099421.1 and mechanical properties by maintaining the molecular weight of the composition and reducing hydrolysis.

[0005] In certain embodiments, at least 10 % of the PHA by weight is recyclate PHA or between about 10% and about 100 % by weight of the PHA is recyclate PHA, for example, about 20%) and 65% by weight of the PHA is recyclate PHA. Also in accordance with the invention, a composition comprising a polyhydroxyalkanoate polymer (PHA) and a chain extender is provided, wherein the PHA comprises at least 4% by weight a 4HB component.

[0006] In further related embodiments, the chain extender is a carbodiimide, such as a polymeric carbodiimide or a monomeric carbodiimide. In particular embodiments, the carbodiimide is a 2,6-diisopropylphenyl type carbodiimide. The weight percent of the carbodiimide is between about 0.4 % and about 1.2% of the total composition, for example, about 1%) of the total composition.

[0007] In related embodiments, the composition further includes a branching agent, for example, a peroxide including but not limited to the following: dicumyl peroxide, t-amyl-2- ethylhexyl peroxycarbonate, l,l-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 2,5-dimethyl- 2,5-di(t-butylperoxy) hexane, 2,5-bis(t-butylperoxy)-2,5-dimethylhexane, 2,5-dimethyl-di(t- butylperoxy)hexyne-3, di-t-butyl peroxide, benzoyl peroxide, di-t-amyl peroxide, t-butyl cumyl peroxide, n-butyl-4,4-bis(t-butylperoxy)valerate, l,l-di(t-butylperoxy)-3,3,5-trimethyl- cyclohexane, l,l-di(t-butylperoxy)cyclohexane, l,l-di(t-amylperoxy)-cyclohexane, 2,2-di(t- butylperoxy)butane, ethyl-3,3-di(t-butylperoxy)butyrate, 2,2-di(t-amylperoxy)propane, ethyl-3,3- di(t-amylperoxy)butyrate, t-butylperoxy-acetate, t-amylperoxyacetate, t-butylperoxybenzoate, t- amylperoxybenzoate, and di-t-butyldiperoxyphthalate. In particular embodiments, the peroxide is dicumyl peroxide, 2,5-di(tert-butylperoxy)hexane), or (tert-butylperoxy-2-ethylhexyl carbonate. The concentration of branching agent is between 0.001 to 0.5%> by weight of the PHA in the composition.

[0008] Thus, in certain aspects of the invention, a composition is described having a biobased polyhydroxyalkanoate polymer (PHA), a copolymer of blend thereof with at least 4% by weight of a 4HB component a chain extender and a carbodiimide. In certain embodiments, about 10% and about 100 % by weight or about 20% and 65%o by weight of the PHA is recyclate PHA. In particular embodiments, the weight percent of carbodiimide is between about 0.4 % and 1.2% of the total composition and the carbodiimide is polymeric carbodiimide or a monomeric

1099421.1 carbodiimide. In other embodiments of this aspect of the invention the composition includes a branching agent, such as: dicumyl peroxide, t-amyl-2-ethylhexyl peroxycarbonate, l,l-bis(t- butylperoxy)-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di(t-butylperoxy) hexane, 2,5-bis(t- butylperoxy)-2,5-dimethylhexane, 2,5-dimethyl-di(t-butylperoxy)hexyne-3, di-t-butyl peroxide, benzoyl peroxide, di-t-amyl peroxide, t-butyl cumyl peroxide, n-butyl-4,4-bis(t- butylperoxy)valerate, 1 , 1 -di(t-butylperoxy)-3,3 ,5-trimethyl-cyclohexane, 1 , 1 -di(t- butylperoxy)cyclohexane, l,l-di(t-amylperoxy)-cyclohexane, 2,2-di(t-butylperoxy)butane, ethyl - 3,3-di(t-butylperoxy)butyrate, 2,2-di(t-amylperoxy)propane, ethyl-3,3-di(t-amylperoxy)butyrate, t-butylperoxy-acetate, t-amylperoxyacetate, t-butylperoxybenzoate, t-amylperoxybenzoate, and di-t-butyldiperoxyphthalate. The concentration of branching agent is between 0.001 to 0.5% by weight of the PHA. In these embodiments, one or more other additives may be added including one or more of the following: a nucleating agent, a plasticizer, a flame retardant, a co-agent, a UV absorber, a cross-linking agent, wax or talc. In certain aspect, the PHA is a blend of a poly 3HB and a poly(3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer with 8-14% 4HB by weight that optionally further includes a poly(3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer with 25-33%) 4HB by weight.

[0009] In accordance with other related aspects of the invention, the composition further optionally comprises one or more additives, for example, plasticizers, nucleating agents, fillers such as wax or talc, co-agents, surfactants, flame retardants (such as magnesium hydroxide), UV absorbers, cross-linking agents, thermoplastic polyesters, (e.g., poly succinate, poly butylene succinate adipate or poly butylene adipate terephthalate) and the like.

[0010] A masterbatch composition is also provided, having 33% of the composition and 67%) of the composition PHA. In particular embodiments, the PHA is a copolymer blend of 26- 32% P3HB and 68-74% P3HB-4HB copolymer with 8-14% 4HB by weight. In certain embodiments of the invention, the masterbatch carbodiimide formulation is then added to the other components.

[0011] The invention further relates to a method of preparing the PHA composition comprising at least 4% by weight a 4HB component, comprising combining an initial PHA comprising at least 4% by weight a 4HB component with a chain extender under conditions that cause melting and chain extension of the PHA, wherein the resultant PHA composition has increased mechanical properties compared with the initial PHA. In particular embodiments, the

1099421.1 4HB component is between about 4% to about 30% of the PHA composition, for example, between about 5% to about 10%, between about 7% and about 15%, between about 18% to about 25%. In other embodiments, the 4HB component in the compositions and methods described herein is about 4%, about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 11%, about 12%, about 13%, about 14%, about 15%, about 16%, about 17% , about 18%, about 19%, about 20%), about 21%, about 22%, about 23%, about 24%, about 25%, about 26%, about 27%, about 28%, about 29%, about 30%, about 31%, about 32%, about 33%, about 34%, about 35%, about 36%, about 37%, about38%, about 39%, or about 40% of the PHA component.

[0012] In another related embodiment of the invention, methods of preparing a PHA composition, by reacting an initial PHA having at least 10% recy elate PHA with a branching agent and a chain extender under conditions that cause melting, branching and chain extension of the PHA, wherein the resultant PHA composition has increased mechanical properties compared with the initial PHA are described. For example, at least 11%, at least 12%, at lest 13%, at least 14%, at least 15%, at least 16%, at least 17%, at least 18%, at least 19%, at least 20%, , at least 21%, at least 22%, at least 23%, at least 24%, at least 25%, at least 26%, at least 27%, at least 28%, at least 29%, at least 30%, at least 31%, at least 32%, at least 33%, at least 34%, at least 35%, at least 36%, at least 37%, at least 38%, at least 39%, or at least 40% recyclate PHA is added.

[0013] Articles made with the compositions of the invention and by the methods of the invention are also described including films, sheets or thermoformed articles.

DETAILED DESCRIPTION OF THE INVENTION

[0014] A description of example embodiments of the invention follows.

[0015] In accordance with an embodiment of the invention, polyhydroxyalkanoate compositions with chain extenders are provided that improve the melt strength of PHA compositions, a desirable property for many polymer product applications. Increased melt strength is useful in that it allows the polymers to be formed under a broader temperature range when the polymer is processed, especially in the production of blown film, cast or extruded film, thermoformed articles, profiled extruded articles and the like. Prior to the present invention, a PHA's thermal instability at processing temperatures can accordingly lead to a drop in melt

1099421.1 strength that can cause difficulties in processing these polymers. These problems are addressed by the present invention.

[0016] The specific selection of additives and components of the compositions of the invention further assist in minimizing damage to the PHA polymers due to hydrolysis thereby improving the processing properties of the compositions and surprisingly in some combinations show unexpected synergistic properties. Accordingly, these distinctive compositions of the invention possess appropriate mechanical and rheological properties for a broader spectrum of applications compared with other PHA compositions without chain extenders.

[0017] In addition, the compositions advantageously allow the use of recyclate PHA enabling sustainability by decreasing waste that had traditionally been largely unrecoverable in thermoprocessing. This accomplishment of utilizing recyclate yet maintaining the desirable properties allows for reduced waste in manufacturing and reduced costs.

[0018] The compositions of the invention have improved melt strength and melt stability. In accordance with certain embodiments, the compositions showed synergistic effects with carbodiimide and other additives, e.g., branching agents, fillers, nucleating agents, plasticizers, surfactant, other thermoplastic non-PHA polyesters, UN. absorbers and/or flame retardants. These compositions had improved tensile, flexural and impact mechanical properties. In other related embodiments, the PHA composition with at least 4% by weight 4HB showed improved properties with chain extenders.

[0019] For example, in certain embodiments, the compositions include a PHA polymer comprising a 4HB component, a carbodiimide, a nucleating agent (cyanuric acid or boron nitride), a peroxide branching agent, a co-agent (e.g., diallyl phthalate, pentaerythritol triacrylate or others), wax, talc and optionally a UN. absorber and/or a flame retardant.

[0020] The compositions of the invention have the desired properties for making film, sheets and thermoformed articles as well as other articles for various applications.

[0021] "Recyclate" PHA, as used herein, is synonymous with recycled PHA, regrind PHA and reprocessed PHA, referring to PHA polymer that is intended to undergo a subsequent processing. In other words, the polymer has previously been processed or undergone some treatment, for example formerly processed by extrusion. In accordance with embodiments of the invention, the compositions incorporate recyclate PHA from at least 10% by weight of the total PHA to about 100% by weight of the total PHA. In certain processes such as thermoforming,

1099421.1 between about 20% up to about 65% of the sheet is recycled. Therefore, having the ability to maintain proper mechanical and rheological properties while utilizing recyclate PHA has many advantages. As used herein, the initial processing to make pellets is distinct from, and is not encompassed by, the term "recyclate." However, utilizing PHA from prior injection molding or other processing runs or from consumer PHA collection is intended to be encompassed by the term, recyclate. In compositions with a 4HB component, a benefit in the first processing from pellets is also observed. Further, the selection of specific additives in the compositions of the invention allow for processing of compositions comprising levels of recyclate PHA having a 4HB content.

[0022] Melt strength is a rheological property that can be measured a number of ways. One measure is G'. G' is the polymer storage modulus measured at melt processing temperatures.

[0023] The term "flame retardant" or "flame retardant chemical" refers to a chemical compound that may be added in the compositions described herein during processing to reduce its flammability. In certain embodiments, the addition of the flame retardant provides advantageous properties in combination with the other additives in the compositions of the invention.

[0024] Physical properties and rheological properties of polymeric materials depend on the molecular weight and distribution of the polymer. "Molecular weight" is calculated in a number of different ways. Unless otherwise indicated, "molecular weight" refers to weight average molecular weight.

[0025] "Number average molecular weight" (M_n) represents the arithmetic mean of the distribution, and is the sum of the products of the molecular weights of each fraction, multiplied by its mole fraction (∑Ν_\Μ/-∑Ν).

[0026] "Weight average molecular weight" (M_w) is the sum of the products of the molecular weight of each fraction, multiplied by its weight fraction (∑NjMj²/∑NjM,). M_w is generally greater than or equal to M_n.

POLYHYDROXYALKANOATES (PHAS)

[0027] Polyhydroxyalkanoates are biological polyesters synthesized by a broad range of natural and genetically engineered bacteria as well as genetically engineered plant crops

(Braunegg et al, (1998), J Biotechnology 65:127-161 ; Madison and Huisman, Microbiology and

1099421.1 Molecular Biology Reviews, 63:21-53 (1999); Poirier, 2002, Progress in Lipid Research 41 :131- 155). These polymers are biodegradable thermoplastic materials, produced from renewable resources, with the potential for use in a broad range of industrial applications (Williams & Peoples, CHEMTECH 26:38-44 (1996)).

[0028] Useful microbial strains for producing PHAs, include Alcaligenes eutrophus (renamed as Ralstonia eutropha), Alcaligenes latus, Azotobacter, Aeromonas, Comamonas,

Pseudomonads, and genetically engineered organisms including genetically engineered microbes such as Pseudomonas, Ralstonia and Escherichia co i.

[0029] In general, a PHA is formed by enzymatic polymerization of one or more monomer units inside a living cell. Over 100 different types of monomers have been incorporated into the PHA polymers (Steinbuchel and Valentin, 1995, FEMS Microbiol. Lett. 128:219-228. Examples of monomer units incorporated in PHAs include 2-hydroxybutyrate, lactic acid, glycolic acid, 3- hydroxybutyrate (hereinafter referred to as 3HB), 3-hydroxypropionate (hereinafter referred to as 3HP), 3 -hydroxy valerate (hereinafter referred to as 3HV), 3-hydroxyhexanoate (hereinafter referred to as 3HH), 3-hydroxyheptanoate (hereinafter referred to as 3HHep), 3- hydroxyoctanoate (hereinafter referred to as 3HO), 3-hydroxynonanoate (hereinafter referred to as 3HN), 3 -hydroxy decanoate (hereinafter referred to as 3HD), 3 -hydroxy dodecanoate

(hereinafter referred to as 3HDd), 4-hydroxybutyrate (hereinafter referred to as 4HB), 4- hydroxyvalerate (hereinafter referred to as 4HV), 5 -hydroxy valerate (hereinafter referred to as 5HV), and 6-hydroxyhexanoate (hereinafter referred to as 6HH). 3-hydroxyacid monomers incorporated into PHAs are the (D) or (R) 3-hydroxyacid isomer with the exception of 3HP which does not have a chiral center. In certain embodiments of the invention, the PHA component in the compositions does not include poly lactic acid (PL A).

[0030] In some embodiments, the PHA in the methods described herein is a homopolymer (where all monomer units are the same). Examples of PHA homopolymers include poly 3- hydroxyalkanoates {e.g., poly 3-hydroxypropionate (hereinafter referred to as P3HP), poly 3- hydroxybutyrate (hereinafter referred to as P3HB) and poly 3 -hydroxy valerate), poly 4- hydroxyalkanoates (e.g., poly 4-hydroxybutyrate (hereinafter referred to as P4HB), or poly 4- hydroxyvalerate (hereinafter referred to as P4HV)) and poly 5-hydroxyalkanoates (e.g., poly 5- hydroxy valerate (hereinafter referred to as P5HV)).

1099421.1 [0031] In certain embodiments, the starting (initial) PHA can be a copolymer (containing two or more different monomer units) in which the different monomers are randomly distributed in the polymer chain. Examples of PHA copolymers include poly 3-hydroxybutyrate-co-3- hydroxypropionate (hereinafter referred to as PHB3HP), poly 3-hydroxybutyrate-co-4- hydroxybutyrate (hereinafter referred to as P3HB4HB), poly 3-hydroxybutyrate-co-4- hydroxy valerate (hereinafter referred to as PHB4HV), poly 3-hydroxybutyrate-co-3- hydroxyvalerate (hereinafter referred to as PHB3HV), poly 3-hydroxybutyrate-co-3- hydroxyhexanoate (hereinafter referred to as PHB3HH) and poly 3-hydroxybutyrate-co-5- hydroxy valerate (hereinafter referred to as PHB5HV).

[0032] By selecting the monomer types and controlling the ratios of the monomer units in a given PHA copolymer a wide range of material properties can be achieved. Although examples of PHA copolymers having two different monomer units have been provided, the PHA can have more than two different monomer units (e.g. , three different monomer units, four different monomer units, five different monomer units, six different monomer units). An example of a PHA having 4 different monomer units would be PHB-co-3HH-co-3HO-co-3HD or PHB-co-3- HO-co-3HD-co-3HDd (these types of PHA copolymers are hereinafter referred to as PHB3HX). Typically where the PHB3HX has 3 or more monomer units the 3HB monomer is at least 70% by weight of the total monomers, preferably 85% by weight of the total monomers, most preferably greater than 90% by weight of the total monomers for example 92%, 93%, 94%, 95%, 96%) by weight of the copolymer and the HX comprises one or more monomers selected from 3HH, 3HO, 3HD, 3HDd.

[0033] The homopolymer (where all monomer units are identical) P3HB and 3- hydroxybutyrate copolymers (P3HB3HP, P3HB4HB, P3HB3HV, P3HB4HV, P3HB5HV, P3HB3HHP, hereinafter referred to as PHB copolymers) containing 3-hydroxybutyrate and at least one other monomer are of particular interest for commercial production and applications. It is useful to describe these copolymers by reference to their material properties as follows. Type 1 PHB copolymers typically have a glass transition temperature (Tg) in the range of 6 °C to -10 °C, and a melting temperature TM of between 80°C to 180 °C. Type 2 PHB copolymers typically have a Tg of -20 °C to-50°C and Tm of 55 °C to 90°C. In particular embodiments, the Type 2 copolymer has a phase component with a T_g of -15 °C to -45 °C and no Tm.

1099421.1 _

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[0034] Preferred Type 1 PHB copolymers have two monomer units have a majority of their monomer units being 3-hydroxybutyrate monomer by weight in the copolymer, for example, greater than 78% 3-hydroxybutyrate monomer. Preferred PHB copolymers for this invention are biologically produced from renewable resources and are selected from the following group of PHB copolymers:

[0035] PHB3HV is a Type 1 PHB copolymer where the 3HV content is in the range of 3% to 22% by weight of the polymer and preferably in the range of 4% to 15% by weight of the copolymer for example: 4% 3HV; 5% 3HV; 6% 3HV; 7% 3HV; 8% 3HV; 9% 3HV; 10% 3HV; 11% 3HV; 12% 3HV; 13% 3HV; 14% 3HV; 15% 3HV; 16% 3HV, 17% 3HV; 18% 3HV; 19% 3HV; 20% 3HV, 21% 3HV, or 22%

[0036] PHB3HP is a Type 1 PHB copolymer where the 3HP content is in the range of 3% to 15% by weight of the copolymer and preferably in the range of 4% to 15% by weight of the copolymer for example: 4% 3 HP; 5% 3 HP; 6% 3 HP; 7% 3 HP; 8% 3 HP; 9% 3 HP; 10% 3 HP; 1 1% 3 HP; 12% 3 HP. 13% 3 HP; 14% 3 HP; 15% 3 HP.

[0037] PHB4HB is a Type 1 PHB copolymer where the 4HB content is in the range of 3% to 15%) by weight of the copolymer and preferably in the range of 4% to 15% by weight of the copolymer for example: 4% 4HB; 5% 4HB; 6% 4HB; 7% 4HB; 8% 4HB; 9% 4HB; 10% 4HB; 11% 4HB; 12% 4HB; 13% 4HB; 14% 4HB; 15% 4HB.

[0038] PHB4HV is a Type 1 PHB copolymer where the 4HV content is in the range of 3% to 15%) by weight of the copolymer and preferably in the range of 4% to 15% by weight of the copolymer for example: 4% 4HV; 5% 4HV; 6% 4HV; 7% 4HV; 8% 4HV; 9% 4HV; 10% 4HV; 1 1% 4HV; 12% 4HV; 13% 4HV; 14% 4HV; 15% 4HV.

[0039] PHB5HV is a Type 1 PHB copolymer where the 5HV content is in the range of 3% to 15% by weight of the copolymer and preferably in the range of 4% to 15% by weight of the copolymer for example: 4% 5HV; 5% 5HV; 6% 5HV; 7% 5HV; 8% 5HV; 9% 5HV; 10% 5HV; 11% 5HV; 12% 5HV; 13% 5HV; 14% 5HV; 15% 5HV.

[0040] PHB3HH is a Type 1 PHB copolymer where the 3HH content is in the range of 3% to 15% by weight of the copolymer and preferably in the range of 4% to 15% by weight of the copolymer for example: 4% 3HH; 5% 3HH; 6% 3HH; 7% 3HH; 8% 3HH; 9% 3HH; 10% 3HH; 1 1% 3HH; 12% 3HH; 13% 3HH; 14% 3HH; 15% 3HH;

1099421.1 _

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[0041] PHB3HX is a Type 1 PHB copolymer where the 3HX content is comprised of 2 or more monomers selected from 3HH, 3HO, 3HD and 3HDd and the 3HX content is in the range of 3% to 12% by weight of the copolymer and preferably in the range of 4% to 10% by weight of the copolymer for example: 4% 3HX; 5% 3HX; 6% 3HX; 7% 3HX; 8% 3HX; 9% 3HX; 10% 3HX by weight of the copolymer.

[0042] Type 2 PHB copolymers have a 3HB content of between 80% and 5% by weight of the copolymer, for example 80%, 75%, 70%, 65%, 60%, 55%, 50%, 45%, 40%, 35%, 30%, 25%, 20%, 15%, 10%, 5% by weight of the copolymer.

[0043] PHB4HB is a Type 2 PHB copolymer where the 4HB content is in the range of 20% to 60% by weight of the copolymer and preferably in the range of 25% to 50% by weight of the copolymer for example: 25% 4HB; 30% 4HB; 35% 4HB; 40% 4HB; 45% 4HB; 50% 4HB by weight of the copolymer.

[0044] PHB5HV is a Type 2 PHB copolymer where the 5HV content is in the range of 20% to 60% by weight of the copolymer and preferably in the range of 25% to 50% by weight of the copolymer for example: 25% 5HV; 30% 5HV; 35% 5HV; 40% 5HV; 45% 5HV; 50% 5HV by weight of the copolymer.

[0045] PHB3HH is a Type 2 PHB copolymer where the 3HH is in the range of 35% to 95% by weight of the copolymer and preferably in the range of 40% to 80% by weight of the copolymer for example: 40% 3HH; 45% 3HH; 50% 3HH; 55% 3HH, 60% 3HH; 65% 3HH; 70% 3HH; 75% 3HH; 80% 3HH by weight of the copolymer.

[0046] PHB3HX is a Type 2 PHB copolymer where the 3HX content is comprised of 2 or more monomers selected from 3HH, 3HO, 3HD and 3HDd and the 3HX content is in the range of 30% to 95% by weight of the copolymer and preferably in the range of 35% to 90% by weight of the copolymer for example: 35% 3HX; 40% 3HX; 45% 3HX; 50% 3HX; 55% 3HX 60% 3HX; 65% 3HX; 70% 3HX; 75% 3HX; 80% 3HX; 85% 3HX; 90% 3HX by weight of the copolymer.

[0047] PHAs for use in the methods, compositions and pellets described in this invention are selected from : PHB or a Type 1 PHB copolymer; a PHA blend of PHB with a Type 1 PHB copolymer where the PHB content by weight of PHA in the PHA blend is in the range of 5% to 95% by weight of the PHA in the PHA blend; a PHA blend of PHB with a Type 2 PHB copolymer where the PHB content by weight of the PHA in the PHA blend is in the range of 5%

1099421.1 to 95% by weight of the PHA in the PHA blend; a PHA blend of a Type 1 PHB copolymer with a different Type 1 PHB copolymer and where the content of the first Type 1 PHB copolymer is in the range of 5% to 95% by weight of the PHA in the PHA blend; a PHA blend of a Type 1 PHB copolymer with a Type 2 PHA copolymer where the content of the Type 1 PHB copolymer is in the range of 30% to 95% by weight of the PHA in the PHA blend; a PHA blend of PHB with a Type 1 PHB copolymer and a Type 2 PHB copolymer where the PHB content is in the range of 10% to 90% by weight of the PHA in the PHA blend, where the Type 1 PHB copolymer content is in the range of 5% to 90% by weight of the PHA in the PHA blend and where the Type 2 PHB copolymer content is in the range of 5% to 90%> by weight of the PHA in the PHA blend.

[0048] The PHA blend of PHB with a Type 1 PHB copolymer is a blend of PHB with PHB3HP where the PHB content in the PHA blend is in the range of 5% to 90% by weight of the PHA in the PHA blend and the 3 HP content in the PHB 3 HP is in the range of 7% to 15% by weight of the PHB3HP.

[0049] The PHA blend of PHB with a Type 1 PHB copolymer is a blend of PHB with PHB3HV where the PHB content of the PHA blend is in the range of 5% to 90% by weight of the PHA in the PHA blend and the 3HV content in the PHB3HV is in the range of 4% to 22% by weight of the PHB3HV.

[0050] The PHA blend of PHB with a Type 1 PHB copolymer is a blend of PHB with PHB4HB where the PHB content of the PHA blend is in the range of 5% to 90% by weight of the PHA in the PHA blend and the 4HB content in the PHB4HB is in the range of 4% to 15% by weight of the PHB4HB.

[0051] The PHA blend of PHB with a Type 1 PHB copolymer is a blend of PHB with PHB4HV where the PHB content of the PHA blend is in the range of 5% to 90% by weight of the PHA in the PHA blend and the 4HV content in the PHB4HV is in the range of 4% to 15% by weight of the PHB4HV.

[0052] The PHA blend of PHB with a Type 1 PHB copolymer is a blend of PHB with PHB5HV where the PHB content of the PHA blend is in the range of 5% to 90% by weight of the PHA in the PHA blend and the 5HV content in the PHB5HV is in the range of 4% to 15% by weight of the PHB5HV.

[0053] The PHA blend of PHB with a Type 1 PHB copolymer is a blend of PHB with PHB3HH where the PHB content of the PHA blend is in the range of 5% to 90% by weight of

1099421.1 the PHA in the PHA blend and the 3HH content in the PHB3HH is in the range of 4% to 15% by weight of the PHB3HH.

[0054] The PHA blend of PHB with a Type 1 PHB copolymer is a blend of PHB with PHB3HX where the PHB content of the PHA blend is in the range of 5% to 90% by weight of the PHA in the PHA blend and the 3HX content in the PHB3HX is in the range of 4% to 15% by weight of the PHB3HX.

[0055] The PHA blend is a blend of a Type 1 PHB copolymer selected from the group PHB3HV, PHB 3 HP, PHB4HB, PHBV, PHV4HV, PHB5HV, PHB3HH and PHB3HX with a second Type 1 PHB copolymer which is different from the first Type 1 PHB copolymer and is selected from the group PHB3HV, PHB3HP, PHB4HB, PHBV, PHV4HV, PHB5HV, PHB3HH and PHB3HX where the content of the First Type 1 PHB copolymer in the PHA blend is in the range of 10% to 90% by weight of the total PHA in the blend.

[0056] The PHA blend of PHB with a Type 2 PHB copolymer is a blend of PHB with PHB4HB where the PHB content in the PHA blend is in the range of 30% to 95% by weight of the PHA in the PHA blend and the 4HB content in the PHB4HB is in the range of 20% to 60% by weight of the PHB4HB.

[0057] The PHA blend of PHB with a Type 2 PHB copolymer is a blend of PHB with PHB5HV where the PHB content in the PHA blend is in the range of 30% to 95% by weight of the PHA in the PHA blend and the 5HV content in the PHB5HV is in the range of 20% to 60% by weight of the PHB5HV.

[0058] The PHA blend of PHB with a Type 2 PHB copolymer is a blend of PHB with PHB3HH where the PHB content in the PHA blend is in the range of 35% to 95% by weight of the PHA in the PHA blend and the 3HH content in the PHB3HH is in the range of 35% to 90% by weight of the PHB3HX.

[0059] The PHA blend of PHB with a Type 2 PHB copolymer is a blend of PHB with PHB3HX where the PHB content in the PHA blend is in the range of 30% to 95% by weight of the PHA in the PHA blend and the 3HX content in the PHB3HX is in the range of 35% to 90% by weight of the PHB3HX.

[0060] The PHA blend is a blend of PHB with a Type 1 PHB copolymer and a Type 2 PHB copolymer where the PHB content in the PHA blend is in the range of 10% to 90% by weight of the PHA in the PHA blend, the Type 1 PHB copolymer content of the PHA blend is in the range

1099421.1 of 5% to 90% by weight of the PHA in the PHA blend and the Type 2 PHB copolymer content in the PHA blend is in the range of 5% to 90% by weight of the PHA in the PHA blend.

[0061] For example, a PHA blend can have a PHB content in the PHA blend in the range of 10% to 90% by weight of the PHA in the PHA blend, a PHB3HV content in the PHA blend in the range 5% to 90%> by weight of the PHA in the PHA blend, where the 3HV content in the PHB3HV is in the range of 3% to 22% by weight of the PHB3HV, and a PHBHX content in the PHA blend in the range of 5% to 90% by weight of the PHA in the PHA blend where the 3HX content in the PHBHX is in the range of 35% to 90% by weight of the PHBHX.

[0062] For example, a PHA blend can have a PHB content in the PHA blend in the range of 10% to 90% by weight of the PHA in the PHA blend, a PHB3HV content in the PHA blend in the range 5% to 90% by weight of the PHA in the PHA blend, where the 3HV content in the PHB3HV is in the range of 3% to 22% by weight of the PHB3HV, and a PHB4HB content in the PHA blend in the range of 5% -to 90% by weight of the PHA in the PHA blend where the 4HB content in the PHB4HB is in the range of 20% to 60% by weight of the PHB4HB.

[0063] For example, a PHA blend can have a PHB content in the PHA blend in the range of 10% to 90% by weight of the PHA in the PHA blend, a PHB3HV content in the PHA blend in the range 5% to 90% by weight of the PHA in the PHA blend, where the 3HV content in the PHB3HV is in the range of 3% to 22% by weight of the PHB3HV, and a PHB5HV content in the PHA blend in the range of 5% to 90% by weight of the PHA in the PHA blend where the 5HV content in the PHB5HV is in the range of 20% to 60% by weight of the PHB5HV.

[0064] For example, a PHA blend can have a PHB content in the PHA blend in the range of 10% to 90% by weight of the PHA in the PHA blend, a PHB4HB content in the PHA blend in the range 5% to 90% by weight of the PHA in the PHA blend, where the 4HB content in the PHB4HB is in the range of 4% to 15% by weight of the PHB4HB, and a PHB4HB content in the PHA blend in the range of 5% to 90% by weight of the PHA in the PHA blend where the 4HB content in the PHB4HB is in the range of 20% to 60% by weight of the PHB4HB.

[0065] For example, a PHA blend can have a PHB content in the PHA blend in the range of 10% to 90% by weight of the PHA in the PHA blend, a PHB4HB content in the PHA blend in the range 5% to 90% by weight of the PHA in the PHA blend, where the 4HB content in the PHB4HB is in the range of 4% to 15% by weight of the PHB4HB, and a PHB5HV content in the

1099421.1 PHA blend in the range of 5% to 90% by weight of the PHA in the PHA blend and where the 5HV content in the PHB5HV is in the range of 30% to 90% by weight of the PHB5HV.

[0066] For example, a PHA blend can have a PHB content in the PHA blend in the range of 10% to 90% by weight of the PHA in the PHA blend, a PHB4HB content in the PHA blend in the range 5% to 90% by weight of the PHA in the PHA blend, where the 4HB content in the PHB4HB is in the range of 4% to 15% by weight of the PHB4HB, and a PHB3HX content in the PHA blend in the range of 5% to 90% by weight of the PHA in the PHA blend and where the 3HX content in the PHB3HX is in the range of 35% to 90% by weight of the PHB3HX.

[0067] For example, a PHA blend can have a PHB content in the PHA blend in the range of 10% to 90%) by weight of the PHA in the PHA blend, a PHB4HV content in the PHA blend in the range 5% to 90% by weight of the PHA in the PHA blend, where the 4HV content in the PHB4HV is in the range of 3% to 15% by weight of the PHB4HV, and a PHB5HV content in the PHA blend in the range of 5% to 90% by weight of the PHA in the PHA blend where the 5HV content in the PHB5HV is in the range of 30% to 90% by weight of the PHB5HV.

[0068] For example, a PHA blend can have a PHB content in the PHA blend in the range of 10% to 90% by weight of the PHA in the PHA blend, a PHB3HH content in the PHA blend in the range 5% to 90% by weight of the PHA in the PHA blend, where the 3HH content in the PHB3HH is in the range of 3% to 15% by weight of the PHB3HH, and a PHB4HB content in the PHA blend in the range of 5% to 90% by weight of the PHA in the PHA blend where the 4HB content in the PHB4HB is in the range of 20% to 60% by weight of the PHB4HB.

[0069] For example, a PHA blend can have a PHB content in the PHA blend in the range of 10% to 90% by weight of the PHA in the PHA blend, a PHB3HH content in the PHA blend in the range 5% to 90% by weight of the PHA in the PHA blend, where the 3HH content in the PHB3HH is in the range of 3% to 15% by weight of the PHB3HH, and a PHB5HV content in the PHA blend in the range of 5% to 90% by weight of the PHA in the PHA blend where the 5HV content in the PHB5HV is in the range of 20% to 60% by weight of the PHB5HV.

[0070] For example, a PHA blend can have a PHB content in the PHA blend in the range of 10% to 90% by weight of the PHA in the PHA blend, a PHB3HH content in the PHA blend in the range 5% to 90% by weight of the PHA in the PHA blend, where the 3HH content in the PHB3HH is in the range of 3% to 15% by weight of the PHB3HH, and a PHB3HX content in the

1099421.1 .

- 15 -

PHA blend in the range of 5% to 90% by weight of the PHA in the PHA blend where the 3HX content in the PHB3HX is in the range of 35% to 90% by weight of the PHB3HX.

[0071] For example, a PHA blend can have a PHB content in the PHA blend in the range of

10% to 90% by weight of the PHA in the PHA blend, a PHB3HX content in the PHA blend in the range 5% to 90% by weight of the PHA in the PHA blend, where the 3HX content in the

PHB3HX is in the range of 3% to 12% by weight of the PHB3HX, and a PHB3HX content in the

[0072] For example, a PHA blend can have a PHB content in the PHA blend in the range of

PHB3HX is in the range of 3% to 12% by weight of the PHB3HX, and a PHB4HB content in the

PHA blend in the range of 5% to 90% by weight of the PHA in the PHA blend where the 4HB content in the PHB4HB is in the range of 20% to 60% by weight of the PHB4HB.

[0073] For example, a PHA blend can have a PHB content in the PHA blend in the range of

PHB3HX is in the range of 3% to 12% by weight of the PHB3HX, and a PHB5HV content in the

PHA blend in the range of 5% to 90% by weight of the PHA in the PHA blend where the 5HV content in the PHB5HV is in the range of 20% to 60% by weight of the PHB5HV.

[0074] The PHA blend can be a blend as disclosed in U.S. Published Application No.

US 2004/0220355, by Whitehouse, published November 4, 2004, which is incorporated herein by reference in its entirety.

[0075] Microbial systems for producing the PHB copolymer PHBV are disclosed in, e.g., U.S. Patent No. 4,477,654 to Holmes, which is incorporated herein by reference in its entirety. U.S. Published Application No. US 2002/0164729 (also incorporated herein by reference in its entirety) by Skraly and Sholl describes useful systems for producing the PHB copolymer PHB4HB. Useful processes for producing the PHB copolymer PHB3HH have been described (Lee et al, 2000, Biotechnology and Bioengineering 67:240-244; Park et al, 2001,

Biomacromolecules 2:248-254). Processes for producing the PHB copolymers PHB3HX have been described by Matsusaki et al. {Biomacromolecules 2000, 1 : 17-22).

1099421.1 [0076] In determining the molecular weight techniques such as gel permeation chromatography (GPC) can be used. In the methodology, a polystyrene standard is utilized. The PHA can have a polystyrene equivalent weight average molecular weight (in daltons) of at least 500, at least 10,000, or at least 50,000 and/or less than 2,000,000, less than 1,000,000, less than 1,500,000, and less than 800,000. In certain embodiments, preferably, the PHAs generally have a weight-average molecular weight in the range of 100,000 to 700,000. For example, the molecular weight range for PHB and Type 1 PHB copolymers for use in this application are in the range of 400,000 daltons to 1.5 million daltons as determined by GPC method and the molecular weight range for Type 2 PHB copolymers for use in the application 100,000 to 1.5 million daltons.

[0077] In certain embodiments, the PHA can have a linear equivalent weight average molecular weight of from about 150,000 Daltons to about 500,000 Daltons and a polydispersity index of from about 2.5 to about 8.0. As used herein, weight average molecular weight and linear equivalent weight average molecular weight are determined by gel permeation

chromatography, using, e.g., chloroform as both the eluent and diluent for the PHA samples. Calibration curves for determining molecular weights are generated using linear polystyrenes as molecular weight standards and a 'log MW vs elution volume' calibration method.

COMPOSITIONS OF THE INVENTION

[0078] In certain embodiments of the invention, the polymers described above for use in the methods and compositions are blended in the presence of chain extenders, one or more additives such as but not limited to cross-linking agents and optionally branching agents and co-agents to form compositions with improved properties. These components of the compositions of the invention are discussed below.

[0079] In certain aspects of the invention, the compositions include, a PHA polymer such as poly-3-hydroxybutyrate homopolymer, a blend of 55-65% poly 3-hydroxybutyrate

homopolymer (P3HB) and 35-45% of poly 3-hydroxybutyrate-co-4-hydroxybutyrate copolymer (P3HB-4HB copolymer) with 8-14% 4-hydroxybutryate (4HB) by weight, a blend of 17-23% P3HB and 77-83% P3HB-4HB copolymer with 8-14% 4HB by weight, or a blend of 34-38% P3HB, 22-26% P3HB-4HB copolymer with 8-14% 4HB by weight and 38-42% P3HB-4HB copolymer with 25-33% 4HB by weight, combined with a nucleating agent (e.g., cyanuric acid or

1099421.1 _

- 17 - boron nitride) a plasticizer, a chain extender (e.g., a carbodiimide), optionally including a co- agent (diallyl phthalate or pentaerithritol triacrylate, a branching agent (peroxide), a plasticizer and optionally talc, wax, U.V. absorber or combinations of talc, wax or U.V. absorber.

[0080] In certain embodiments, the composition includes a blend of a poly-3- hydroxybutyrate homopolymer and a P3HB-4HB copolymer, a branching agent (e.g., a peroxide compound such as peroxides under the tradename TRIGONOX® ), a chain extender (e.g., carbodiimide (STABAXOL® Brand carbodiimides) and a co-agent (pentaerythritol triacrylate, diallyl phthalate and the like). These compositions also may include one or more additives, such as U.V. absorbers, flame retardants, surfactants, calcium carbonate, processing aids and the like.

CHAIN EXTENDERS

[0081] In the compositions and methods of the invention, chain extenders are included as an additive and result in providing advantageous properties to the composition. Chain extenders are used to increase the molecular weight of the polymer by solid state polymerization or reactive extrusion. The compound class of carbodiimides are examples of chain extenders. A

carbodiimide has the functional group (N=C=N)_n (n is 1-60) and can readily react with water to form ureas. Compounds containing the carbodiimide functional group are therefore used as dehydration agents. Additionally, they are often used to activate carboxylic acids towards amide or ester formation. These chain extenders are referred to as anti-hydrolysis stabilizers.

Monomeric carbodiimides contain one functional group (N=C=N) while polymeric

carbodiimides have more than one functional group.

[0082] Carbodiimide can be formed by dehydration of urea or from thiourea, by subjecting various kinds of polyisocyanates to a decarboxylation condensation reaction with an

organophosphorus compound or an organometallic compound as a catalyst, at temperature of not lower than about 70°C. Methods disclosed in U.S. Patent No. 7,1291,90, or U.S. Patent No 4,965,302 and Bull. Soc. Chim. France, vol.1360, 727-732 (1951) the entire disclosures of which are herein incorporated by reference.

[0083] Examples of carbodiimides that can advantageously be used with PHA's include commercial carbodiimides such as those sold under the tradename STABAXOL® by Rhein Chemie Rheinau GmbH (Mannheim, Germany) (e.g., STABAXOL®-P, STABAXOL® 400), and CARBODILITE® by Nisshinbo Chemical Inc. Tokyo, Japan (e.g., CARBODILITE® SV-02

1099421.1 _

- 18 - and V-02-L2, C ARB ODILITE® LA-1 and HMV-8CA and carbodiimides described in U.S. Patent Nos. 7,361,701 ; 7,273,902, 6,846,860 and 7,368,493). These chain extenders are referred to as anti-hydrolysis stabilizers.

[0084] Other useful carbodiimides include but are not limited to: dicyclohexyl carbodiimide, diisopropyl carbodiimide, dimethyl carbodiimide, diisobutyl carbodiimide, dioctyl carbodiimide, octyldecyl carbodiimide, di-t-butyl carbodiimide, t-butylisopropyl carbodiimide, dibenzyl carbodiimide, diphenyl carbodiimide, N-octadecyl-N'-phenylcarbodiimide, N-benzyl-N'- phenylcarbodiimide, N-benzyl-N'-tolylcarbodiimide, di-o-toluoylcarbodiimide, di-p- toluoylcarbodiimide, bis(p-nitrophenyl)carbodiimide, bis(p-aminophenyl)carbodiimide, bis(p- hydroxyphenyl)carbodiimide, bis(p-chlorophenyl)carbodiimide, bis(o- chlorophenyl)carbodiimide, bis(o-ethylphenyl)carbodiimide, bis(p-ethylphenyl)carbodiimide, bis(o-isopropylphenyl)carbodiimide, bis(p-isopropylphenyl)carbodiimide, bis(o- isobutylphenyl)carbodiimide, bis(p-isobutylphenyl)carbodiimide, bis(2,5- dichlorophenyl)carbodiimide, p-phenylenebis(o-toluoylcarbodiimide), p- phenylenebis(cyclohexylcarbodiimide), p-phenylenebis(p-chlorophenylcarbodiimide), 2,6,2', 6'- tetraisopropyldiphenyl carbodiimide, hexamethylenebis(cyclohexylcarbodiimide),

ethylenebis(phenylcarbodiimide), ethylenebis(cyclohexylcarbodiimide), bis(2,6- dimethylphenyl)carbodiimide, bis(2,6-diethylphenyl)carbodiimide, bis(2-ethyl-6- isopropylphenyl)carbodiimide, bis(2-butyl-6-isopropylphenyl)carbodiimide, bis(2,6- diisopropylphenyl)carbodiimide, bis(2,6-di-t-butylphenyl)carbodiimide, bis(2,4,6- trimethylphenyl)carbodiimide, bis(2,4,6-triisopropylphenyl)carbodiimide, bis(2,4,6- tributylphenyl)carbodiimide, di-beta-naphthylcarbodiimide, N-tolyl-N'-cyclohexylcarbodiimide and N-tolyl-N'-phenylcarbodiimide. poly(cyclooctylene carbodiimide), poly(l,4-dimethylene cyclohexylene carbodiimide), poly(cyclohexylene carbodiimide, poly(ethylene carbodiimide), poly(butylene carbodiimide), poly(isobutylene carbodiimide), poly(nonylene carbodiimide), poly(dodecylene carbodiimide), poly(neopentylene carbodiimide), poly(l,4-dimethylene phenylene carbodiimide), poly(2,2',6,6-tetra-isopropyl-diphenylene carbodiimide), (Stabaxol ®D), poly(2,4,6-triisopropyl-l,3 -phenylene carbodiimide) (Stabaxol®P-IOO), poly(l,3,5- triisopropyl-phenylene-2,4-carbodiimide), poly(tolyl carbodiimide), poly(4,4'- diphenylmethane carbodiimide), poly(3,3'-dimethyl-4,4'-biphenylene carbodiimide), poly(p-phenylene

carbodiimide), poly(m-phenylene carbodiimide), poly(3,3'-dimethyl-4,4'-diphenylmethane

1099421.1 carbodiimide), poly(naphthylene carbodiimide), poly(isophorone carbodiimide), poly(cumene carbodiimide), p-phenylene bis(ethylcarbodiimide), 1,6-hexamethylene bis(ethylcarbodiimide), 1 ,8-octamethylene bis(ethylcarbodiimide), 1,10-decamethylene bis(ethylcarbodiimide), l ,12dodecamethylene bis(ethyl carbodiimide), naphthalene diimide, perylene diimide, perylene tetracarboxylic diimide, any one disclosed in U.S. Pat. No. 4,965,302, or combinations of two or more thereof, N1N'- dicyclohexylcarbodiimide, Ν,Ν'-diisopropylcarbodiimide, l-ethyl-3-(3- dimethyl aminopropyl) carbodiimide hydrochloride, NIN'-diphenylcarbodiimide, N,N'-di-2,6- diisopropylphenylcarbodiimide, or combinations or mixtures of two or more thereof.

[0085] Additives such as N-hydroxybenzotriazole or N-hydroxysuccinimides are often added along with carbodiimides to increase yields and decrease side reactions of carbodiimides. These additives can optionally be used in the compositions of the invention at amounts determined to be beneficial, such as at 0.05% to about 1%.

[0086] In other embodiments, the carbodiimide is a modified carbodiimide, for example the carbodiimide has been modified to incorporate isocyanate end groups, see for example U.S. Patent Application Publication No. 2009/0274885, incorporated herein by reference in its entirety.

[0087] Preferably, said chain extenders are added to the compositions according to the invention in a quantity of about 0.05 to about 20% by weight, for example, about 0.1% to about 10%i. In certain examples, the range is abut 0.05 to about 1.5%, for example, about 0.1 to about 1.2 %, more preferably about 0.4 to about 1 % by weight. In certain embodiment, the chain extender is about 0.1%, about 0.2%, about 0.3%, 0.4%, about 0.5%, about 0.6%, about 0.7%, about 0.8%), about 0.9%, or about 1%.

[0088] The chain extenders can also be prepared as a masterbatch for example, by incorporating the carbodiimide in a PHA blend and producing pellets of the resultant

composition for addition to subsequent processing compositions. In a masterbatch, the concentration of the chain extender is higher than the final amount for the product to allow for proportionate mixing of the additive in the final composition. For example, in preparing a masterbatch, 33% of the carbodiimide can be compounded in about 67% of a PHA blend composition, e.g., a PHA blend of about 20% of a poly(3-hydroxybutyrate-co-4- hydroxybutyrate) copolymer with about 4.5% 4HB and about 80% of a poly(3-hydroxybutyrate- co-4-hydroxybutyrate) copolymer with about 9% 4HB. In other embodiments, the resins for

1099421.1 preparing the masterbatch include blends of P3HB homopolymer and P3HB-co-4HB copolymers. In certain embodiments, the blends have the following composition: PHA A - a blend of 55-65% P3HB and 35-45% P3HB-4HB copolymer with 8-14% 4HB by weight; PHA B: a blend of 15-25% P3HB, 75-85% P3HB-4HB copolymer with 8-14% 4HB by weight.

[0089] A typical formulation for a crosslinking agent such as JONCRYL® masterbatch would be as follows: 60 to 90% of a copolymer PHA blend, 0-1 % nucleating agent and 10-40%) by weight JONCRYL® ADR-4368CS or other epoxy functional compounds discussed below.

[0090] A typical formulation for a carbodiimide masterbatch would be as follows: 60 to 90% of a copolymer PHA blend, 0-1% nucleating agent and 10-40%) by weight carbodiimide.

[0091] In certain embodiments of the invention, the carbodiimide in combination with certain other additives in the PHA compositions of the invention have synergistic properties, such as increased melt strength and stability and/or increased mechanical properties as measured by tensile elongation, impact strength and flexural strength and the like. In accordance with particular embodiments, carbodiimide in combination with peroxide in the PHA compositions showed enhanced properties. In other related embodiments, the incorporation of the additives, such as flame retardants and UV absorbers showed synergistic melt stability properties.

BRANCHING AGENTS

[0092] The branching agents, also referred to as free radical initiators, for use in the compositions and method described herein include organic peroxides. Peroxides are reactive molecules, and can react with polymer molecules or previously branched polymers by removing a hydrogen atom from the polymer backbone, leaving behind a radical. Polymer molecules having such radicals on their backbone are free to combine with each other, creating branched polymer molecules. Branching agents are selected from any suitable initiator known in the art, such as peroxides, azo-dervatives (e.g., azo-nitriles), peresters, and peroxycarbonates. Suitable peroxides for use in the present invention include, but are not limited to, organic peroxides, for example dialkyl organic peroxides such as 2,5-dimethyl-2,5-di(t-butylperoxy) hexane, 2,5-bis(t- butylperoxy)-2,5-dimethylhexane (available from Akzo Nobel as TRIGONOX® 101), 2,5- dimethyl-di(t-butylperoxy)hexyne-3, di-t-butyl peroxide, dicumyl peroxide, benzoyl peroxide, di- t-amyl peroxide, t-amylperoxy-2-ethylhexylcarbonate (TAEC), t-butyl cumyl peroxide, n-butyl- 4,4-bis(t-butylperoxy)valerate, 1 , 1 -di(t-butylperoxy)-3 ,3 ,5-trimethyl-cyclohexane, 1 , 1 -bis(t-

1099421.1 butylperoxy)-3,3,5-trimethylcyclohexane (CPK), l,l-di(t-butylperoxy)cyclohexane, l,l-di(t- amylperoxy)-cyclohexane, 2,2-di(t-butylperoxy)butane, ethyl-3,3-di(t-butylperoxy)butyrate, 2,2- di(t-amylperoxy)propane, ethyl-3,3-di(t-amylperoxy)butyrate, t-butylperoxy-acetate, t- amylperoxyacetate, t-butylperoxybenzoate, t-amylperoxybenzoate, di-t-butyldiperoxyphthalate, and the like. Combinations and mixtures of peroxides can also be used. Examples of free radical initiators include those mentioned herein, as well as those described in, e.g., Polymer Handbook, 3rd Ed., J.Brandrup & E.H. Immergut, John Wiley and Sons, 1989, Ch. 2. Irradiation (e.g., e- beam or gamma irradiation) can also be used to generate polymer branching.

[0093] The efficiency of branching and cross-linking of the PHA polymer blend can also be significantly enhanced by the dispersion of organic peroxides in a cross-linking agent, such as a polymerizable (i.e., reactive) plasticizers. The polymerizable plasticizer should contain a reactive functionality, such as a reactive unsaturated double bond, which increases the overall branching and cross-linking efficiency.

[0094] As discussed above, when peroxides decompose, they form very high energy radicals that can extract a hydrogen atom from the polymer backbone. These radicals have short half- lives, thereby limiting the population of branched molecules that is produced during the active time period. The term branched polymer refers to a PHA with branching of the polymer chain and/or cross-linking of two or more chains. Branching on side chains is also contemplated. Branching increases the melt strength of the polymers and can be branched in any of the ways described in U.S. Patent Nos. 6,620,869; 7,208,535; 6,201,083; 6,156,852; 6,248,862; and 6,096,810 and WO 2010/008447 and WO 2010/008445 (both of which were published in English and designate the United States), all of which are incorporated herein by reference in their entirety.

OTHER ADDITIVES

[0095] In certain embodiments, various other additives are added to the compositions and methods of the invention. Examples of these additives include antioxidants (e.g., agents that protect the thermoplastic composition from degradation by ozone or oxygen, such as a phosphorous antioxidant such as Irgaphos antioxidants from Ciba Specialty Chemicals Ltd., or Adekastab antioxidants from Ashai Denka Kogyo K.K., for example tri (2,4-di-t-butylphenyl) phosphite); pigments, thermal and UV absorbers or stabilizers (such as TINUVIN^® 234 and 326 )

1099421.1 _

- 22 -

, inorganic and organic fillers, plasticizers, nucleating agents, anti-slip agents, anti-blocking agents, waxes, flame retardants, and radical scavengers. Additionally, polyfunctional co-agents such as divinyl benzene, trially cyanurate and the like may be added. Additionally co-agent catalysts can for added with the co-agents e.g., metal catalysts, such as a zinc stearate catalyst. Such additives and co-agents can be added to one or more of these additives for easier incorporation into the polymer. For instance, the co-agent can be mixed with a plasticizer, e.g., a non-reactive plasticizer, e.g. , a citric acid ester, and then compounded with the polymer under conditions to induce branching. Calcium carbonate, talc and waxes can also be added in certain quantities as additives. These additives can be used in amounts effective to provide further improvements in stability against hydrolysis and heat resistance in the compositions of the invention.

[0096] In certain compositions, for example, plasticizers are often used to change the glass transition temperature and modulus of the composition, but surfactants may also be used.

Lubricants may also be used, e.g., in injection molding applications. Plasticizers, surfactants and lubricants may all therefore be included in the overall composition.

[0097] In other embodiments, the blend includes one or more plasticizers. Examples of plasticizers include phthalic compounds (including, but not limited to, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, di-n-octyl phthalate, di-2-ethylhexyl phthalate, diisooctyl phthalate, dicapryl phthalate, dinonyl phthalate, diisononyl phthalate, didecyl phthalate, diundecyl phthalate, dilauryl phthalate, ditridecyl phthalate, dibenzyl phthalate, dicyclohexyl phthalate, butyl benzyl phthalate, octyl decyl phthalate, butyl octyl phthalate, octyl benzyl phthalate, n-hexyl n-decyl phthalate, n-octyl phthalate, and n-decyl phthalate), phosphoric compounds (including, but not limited to, tricresyl phosphate, trioctyl phosphate, triphenyl phosphate, octyl diphenyl phosphate, cresyl diphenyl phosphate, and trichloroethyl phosphate), adipic compounds (including, but not limited to, dibutoxyethoxyethyl adipate (DBEEA), dioctyl adipate, diisooctyl adipate, di-n-octyl adipate, didecyl adipate, diisodecyl adipate, n-octyl n-decyl adipate, n-heptyl adipate, and n-nonyl adipate), sebacic compounds (including, but not limited to, dibutyl sebacate, dioctyl sebacate, diisooctyl sebacate, and butyl benzyl sebacate), azelaic compounds, citric compounds (including, but not limited to, triethyl citrate, acetyl triethyl citrate, tributyl citrate, acetyl tributyl citrate, and acetyl trioctyl citrate), glycolic compounds (including, but not limited to, methyl phthalyl ethyl glycolate, ethyl phthalyl ethyl glycolate, and butyl

1099421.1 phthalyl ethyl glycolate), trimellitic compounds (including, but not limited to, trioctyl trimellitate and tri-n-octyl n-decyl trimellitate), phthalic isomer compounds (including, but not limited to, dioctyl isophthalate and dioctyl terephthalate), ricinoleic compounds (including, but not limited to, methyl acetyl, recinoleate and butyl acetyl recinoleate), polyester compounds (including, but not limited to reaction products of diols selected from butane diol, ethylene glycol, propane 1 ,2 diol, propane 1 ,3 diol, polyethylene glycol, glycerol, diacids selected from adipic acid, succinic acid, succinic anhydride and hydroxyacids such as hydroxystearic acid, epoxidized soy bean oil, chlorinated paraffins, chlorinated fatty acid esters, fatty acid compounds, plant oils, pigments, and acrylic compounds. The plasticizers may be used either alone respectively or in

combinations with each other.

[0098] In certain embodiments, the compositions and methods of the invention include one or more surfactants. Surfactants are generally used to de-dust, lubricate, reduce surface tension, and/or densify. Examples of surfactants include, but are not limited to mineral oil, castor oil, and soybean oil. One mineral oil surfactant is DRAKEOL^® 34, available from Penreco (Dickinson, Texas, USA). MAXSPERSE^® W-6000 and W-3000 solid surfactants are available from Chemax Polymer Additives (Piedmont, South Carolina, USA). Non-ionic surfactants with HLB values ranging from about 2 to about 16 can be used, examples being TWEEN-20, TWEEN-65, Span- 40 and Span 85.

[0099] Anionic surfactants include: aliphatic carboxylic acids such as lauric acid, myristic acid, palmitic acid, stearic acid, and oleic acid; fatty acid soaps such as sodium salts or potassium salts of the above aliphatic carboxylic acids; N-acyl-N-methylglycine salts, N-acyl-N-methyl- beta-alanine salts, N-acylglutamic acid salts, polyoxyethylene alkyl ether carboxylic acid salts, acylated peptides, alkylbenzenesulfonic acid salts, alkylnaphthalenesulfonic acid salts, naphthalenesulfonic acid salt-formalin polycondensation products, melaminesulfonic acid salt- formalin polycondensation products, dialkylsulfosuccinic acid ester salts, alkyl sulfosuccinate disalts, polyoxyethylene alkylsulfosuccinic acid disalts, alkylsulfoacetic acid salts, (alpha- olefmsulfonic acid salts, N-acylmethyltaurine salts, sodium dimethyl 5-sulfoisophthalate, sulfated oil, higher alcohol sulfuric acid ester salts, polyoxyethylene alkyl ether sulfuric acid salts, secondary higher alcohol ethoxysulfates, polyoxyethylene alkyl phenyl ether sulfuric acid salts, monoglysulfate, sulfuric acid ester salts of fatty acid alkylolamides, polyoxyethylene alkyl ether phosphoric acid salts, polyoxyethylene alkyl phenyl ether phosphoric acid salts, alkyl

1099421.1 phosphoric acid salts, sodium alkylamine oxide bistridecylsulfosuccinates, sodium dioctylsulfosuccinate, sodium dihexylsulfosuccinate, sodium dicyclohexylsulfosuccinate, sodium diamylsulfosuccinate, sodium diisobutylsulfosuccinate, alkylamine guanidine polyoxyethanol, disodium sulfosuccinate ethoxylated alcohol half esters, disodium sulfosuccinate ethoxylated nonylphenol half esters, disodium isodecylsulfosuccinate, disodium N- octadecylsulfosuccinamide, tetrasodium N-(l ,2-dicarboxyethyl)-N-octadecylsulfosuccinamide, disodium mono- or didodecyldiphenyl oxide disulfonates, sodium

diisopropylnaphthalenesulfonate, and neutralized condensed products from sodium

naphthalenesulfonate.

[0100] One or more lubricants can also be added to the compositions and methods of the invention. Lubricants are normally used to reduce sticking to hot processing metal surfaces and can include polyethylene, paraffin oils, and paraffin waxes in combination with metal stearates. Other lubricants include stearic acid, amide waxes, ester waxes, metal carboxylates, and carboxylic acids. Lubricants are normally added to polymers in the range of about 0.1 percent to about 1 percent by weight, generally from about 0.7 percent to about 0.8 percent by weight of the compound. Solid lubricants are warmed and melted before or during processing of the blend.

[0101] In film applications of the compositions and methods described herein, anti-block masterbatch may also be added. A suitable example is a slip anti-block masterbatch mixture of erucamide (20% by weight), diatomaceous earth (15% by weight), and nucleant masterbatch (3% by weight), pelleted into PHA (62% by weight). Others are known to those of ordinary skill in the field of polymer processing.

[0102] In certain embodiments, the compositions include a flame retardant. A flame retardant is an additive which inhibits the initiation and/or spread of flame or smoke by inhibiting the combustion reaction in the flame, or by another mechanism. Useful flame retardant additives include water release compounds and organic compounds that include phosphorus and bromine. Examples of water release compounds include but are not limited to aluminum trihydrate, hydrotalcite, antimony trioxide. Brominated flame retardants include but are not limited to decabromodiphenyl ether. Phosphorus compounds include but are not limited to

organophosphinate, red phosphorus, ammonium polyphosphate, aluminum hypophosphite, aromatic phosphates (e.g., triaryl phosphate) and the like. Generally for environmental concerns,

1099421.1 non-halogen flame retardants are used. Flame retardants are generally added to the compositions of the invention in the range of about 1% to about 60% by weight, in certain embodiments, in a range of about 5% to about 30%.

CROSS-LINKING AGENTS

[0103] Cross-linking agents, also referred to as co-agents, used in the methods and compositions of the invention are cross-linking agents comprising two or more reactive functional groups such as epoxides or double bonds. These cross-linking agents modify the properties of the polymer. These properties include, but are not limited to, melt strength or toughness. One type of cross-linking agent is an "epoxy functional compound." As used herein, "epoxy functional compound" is meant to include compounds with two or more epoxide groups capable of increasing the melt strength of polyhydroxyalkanoate polymers by branching, e.g. , end branching as described above.

[0104] When an epoxy functional compound is used as the cross-linking agent in the disclosed methods, a branching agent is optional. As such one embodiment of the invention is a method of branching a starting polyhydroxyalkanoate polymer (PHA), comprising reacting a starting PHA with an epoxy functional compound. Alternatively, the invention is a method of branching a starting polyhydroxyalkanoate polymer, comprising reacting a starting PHA, a branching agent and an epoxy functional compound. Alternatively, the invention is a method of branching a starting polyhydroxyalkanoate polymer, comprising reacting a starting PHA, and an epoxy functional compound in the absence of a branching agent. Such epoxy functional compounds can include epoxy-functional, styrene-acrylic polymers (such as, but not limited to, e.g. , JONCRYL^® ADR-4368 (BASF), or MP-40 (Kaneka)), acrylic and/or polyolefin copolymers and oligomers containing glycidyl groups incorporated as side chains (such as, but not limited to, e.g. , LOTADER^® (Arkema), poly(ethylene-glycidyl methacrylate-co-methacrylate)), and epoxidized oils (such as, but not limited to, e.g., epoxidized soybean, olive, linseed, palm, peanut, coconut, seaweed, cod liver oils, or mixtures thereof, e.g., Merginat ESBO (Hobum, Hamburg, Germany) and EDENOL^® B 316 (Cognis, Dusseldorf, Germany)).

[0105] For example, reactive acrylic or functional acrylic cross-linking agents are used to increase the molecular weight of the polymer in the branched polymer compositions described herein. Such cross-linking agents are sold commercially. BASF, for instance, sells multiple

1099421.1 compounds under the trade name "JONCRYL ," which are described in U.S. Patent No.

6,984,694 to Blasius et al, "Oligomeric chain extenders for processing, post-processing and recycling of condensation polymers, synthesis, compositions and applications," incorporated herein by reference in its entirety. One such compound is JONCRYL^® ADR-4368CS, which is styrene glycidyl methacrylate and is discussed below. Another is MP-40 (Kaneka). Still another is the Petra line from Honeywell, see for example, U.S. Patent No. 5,723,730. Such polymers are often used in plastic recycling (e.g., in recycling of polyethylene terephthalate) to increase the molecular weight (or to mimic the increase of molecular weight) of the polymer being recycled. Such polymers often have the general structure:

Rj and R₂ are H or alkyl

R3 is alkyl

x and y are 1-20

z is 2-20

[0106] E.I. du Pont de Nemours & Company sells multiple reactive compounds under the trade name ELVALOY^®, which are ethylene copolymers, such as acrylate copolymers, elastomeric terpolymers, and other copolymers. One such compound is ELVALOY^® PTW, which is a copolymer of ethylene-n-butyl acrylate and glycidyl methacrylate. Omnova sells similar compounds under the trade names "SX64053," "SX64055," and "SX64056." Other entities also supply such compounds commercially.

[0107] Specific polyfunctional polymeric compounds with reactive epoxy functional groups are the styrene-acrylic copolymers. These materials are based on oligomers with styrene and acrylate building blocks that have glycidyl groups incorporated as side chains. A high number of

1099421.1 epoxy groups per oligomer chain are used, for example 5, greater than 10, or greater than 20. These polymeric materials generally have a molecular weight greater than 3000, specifically greater than 4000, and more specifically greater than 6000. Other types of polyfunctional polymer materials with multiple epoxy groups are acrylic and/or polyolefm copolymers and oligomers containing glycidyl groups incorporated as side chains. A further example of such a polyfunctional carboxy-reactive material is a co- or ter-polymer including units of ethylene and glycidyl methacrylate (GMA), available under the trade name LOTADER^® resin, sold by

Arkema. These materials can further comprise methacrylate units that are not glycidyl. An example of this type is poly(ethylene-glycidyl methacrylate-co-methacrylate).

[0108] Fatty acid esters or naturally occurring oils containing epoxy groups (epoxidized) can also be used. Examples of naturally occurring oils are olive oil, linseed oil, soybean oil, palm oil, peanut oil, coconut oil, seaweed oil, cod liver oil, or a mixture of these compounds. Particular preference is given to epoxidized soybean oil {e.g., Merginat ESBO from Hobum, Hamburg, or EDENOL^® B 316 from Cognis, Dusseldorf), but others may also be used.

[0109] Another type of cross-linking agent (co-agent) is an agent with two or more double bonds. Cross-linking agents with two or more double bond cross-link PHAs by after reacting at the double bonds. Examples of these include: diallyl phthalate, pentaerythritol tetraacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol pentaacrylate, diethylene glycol dimethacrylate, bis(2-methacryloxyethyl)phosphate. In particular

embodiments of the invention, the compositions include a co-agent, diallyl phthalate or pentaerythritol triacrylate.

[0110] In general, it appears that compounds with terminal epoxides may perform better than those with epoxide groups located elsewhere on the molecule.

[0111] Compounds having a relatively high number of end groups are the most desirable. Molecular weight may also play a role in this regard, and compounds with higher numbers of end groups relative to their molecular weight {e.g. , the JONCRYL^® s are in the 3000 - 4000 g/mol range) are likely to perform better than compounds with fewer end groups relative to their molecular weight {e.g. , the Omnova products have molecular weights in the 100,000 - 800,000 g/mol range).

1099421.1 NUCLEATING AGENTS

[0112] In some embodiments, an optional nucleating agent is added as an additive to the composition to aid in its crystallization. Nucleating agents for various polymers are simple substances, metal compounds including composite oxides, for example, carbon black, calcium carbonate, synthesized silicic acid and salts, silica, zinc white, clay, kaolin, basic magnesium carbonate, mica, talc, quartz powder, diatomite, dolomite powder, titanium oxide, zinc oxide, antimony oxide, barium sulfate, calcium sulfate, alumina, calcium silicate, metal salts of organophosphates, and boron nitride; low-molecular organic compounds having a metal carboxylate group, for example, metal salts of such as octylic acid, toluic acid, heptanoic acid, pelargonic acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, cerotic acid, montanic acid, melissic acid, benzoic acid, p-tert-butylbenzoic acid, terephthalic acid, terephthalic acid monomethyl ester, isophthalic acid, and isophthalic acid monomethyl ester; high-molecular organic compounds having a metal carboxylate group, for example, metal salts of such as: carboxyl-group-containing polyethylene obtained by oxidation of polyethylene;

carboxyl-group-containing polypropylene obtained by oxidation of polypropylene; copolymers of olefins, such as ethylene, propylene and butene-1 , with acrylic or methacrylic acid; copolymers of styrene with acrylic or methacrylic acid; copolymers of olefins with maleic anhydride; and copolymers of styrene with maleic anhydride; high-molecular organic compounds, for example: alpha-olefins branched at their 3 -position carbon atom and having no fewer than 5 carbon atoms, such as 3,3 dimethylbutene-l ,3-methylbutene-l ,3-methylpentene-l,3-methylhexene-l , and 3,5,5- trimethylhexene-1 ; polymers of vinylcycloalkanes such as vinyl cyclopentane, vinylcyclohexane, and vinylnorbornane; polyalkylene glycols such as polyethylene glycol and polypropylene glycol; poly(glycolic acid); cellulose; cellulose esters; and cellulose ethers; phosphoric or phosphorous acid and its metal salts, such as diphenyl phosphate, diphenyl phosphite, metal salts of bis(4-tert-butylphenyl) phosphate, and methylene bis-(2,4-tert-butylphenyl)phosphate; sorbitol derivatives such as bis(p-methylbenzylidene) sorbitol and bis(p-ethylbenzylidene) sorbitol; and thioglycolic anhydride, p-toluenesulfonic acid and its metal salts. The above nucleating agents may be used either alone or in combinations with each other. In particular embodiments, the nucleating agent is cyanuric acid. In certain embodiments, the nucleating agent can also be another polymer (e.g., polymeric nucleating agents such as PHB).

1099421.1 [0113] In certain embodiments, the nucleating agent is selected from: cyanuric acid, carbon black, mica talc, silica, boron nitride, clay, calcium carbonate, synthesized silicic acid and salts, metal salts of organophosphates, and kaolin. In particular embodiments, the nucleating agent is cyanuric acid or boron nitride. In other particular embodiments, the cyanuric acid or boron nitride are included as an additive in the compositions of the invention with a plasticizer, a U.V. absorber, and optionally a co-agent, talc and/or wax additives. In certain composition, the PHA polymer has advantageous properties with a select additive composition.

[0114] In various embodiments, where the nucleating agent is dispersed in a liquid carrier, the liquid carrier is a plasticizer, e.g., a citric compound or an adipic compound, e.g., acetylcitrate tributyrate (CITROFLEX^®A4, Vertellus, Inc., High Point, N.C.), or DBEEA

(dibutoxyethoxyethyl adipate), a surfactant, e.g. , Triton X-100, TWEEN-20, TWEEN-65, Span- 40 or Span 85, a lubricant, a volatile liquid, e.g., chloroform, heptane, or pentane, a organic liquid or water.

[0115] In other embodiments, the nucleating agent is aluminum hydroxy diphosphate or a compound comprising a nitrogen-containing heteroaromatic core. The nitrogen-containing heteroaromatic core is pyridine, pyrimidine, pyrazine, pyridazine, triazine, or imidazole.

[0116] In particular embodiments, the nucleating agent can include aluminum hydroxy diphosphate or a compound comprising a nitrogen-containing heteroaromatic core. The nitrogen- containing heteroaromatic core is pyridine, pyrimidine, pyrazine, pyridazine, triazine, or imidazole. The nucleant can have a chemical formula selected from the group consisting of:

Formula 1 Formula 2 Formula 3 Formula 4 Formula 5 and

1099421.1 _^

- 30 -

[0117] Formula 6, and combinations thereof, wherein each Rl is independently H, NR²R², OR², SR², SOR², S0₂R², CN, COR², C0₂R², CONR²R², N0₂, F, CI, Br, or I; and each R² is independently H or Ci-C₆ alkyl.

[0118] The nucleating agent can be a nucleating agent as described in U.S. Published Application No. 2005/0209377, by Allen Padwa, which is herein incorporated by reference in its entirety.

[0119] Another nucleating agent for use in the compositions and methods described herein are milled as described in International Publication No. WO 2009/129499, published in English on October 22, 2009, and which designates the United States, which is herein incorporated by reference in its entirety. Briefly, the nucleating agent is milled in a liquid carrier until at least 5% of the cumulative solid volume of the nucleating agent exists as particles with a particle size of 5 microns or less. The liquid carrier allows the nucleating agent to be wet milled. In other embodiments, the nucleating agent is milled in liquid carrier until at least 10% of the cumulative solid volume, at least 20% of the cumulative solid volume, at least 30% or at least 40%-50% of the nucleating agent can exist as particles with a particle size of 5 microns or less, 2 microns or less or 1 micron or less. In alternative embodiments, the nucleating agents are milled by other methods, such as jet milling and the like. Additionally, other methods can be utilized that reduce the particle size.

[0120] The cumulative solid volume of particles is the combined volume of the particles in dry form in the absence of any other substance. The cumulative solid volume of the particles is determined by determining the volume of the particles before dispersing them in a polymer or liquid carrier by, for example, pouring them dry into a graduated cylinder or other suitable device for measuring volume. Alternatively, cumulative solid volume is determined by light scattering.

1099421.1 APPLICATION OF THE COMPOSITIONS

[0121] For the fabrication of useful articles, the compositions described herein are processed preferably at a temperature above the crystalline melting point of the polymers but below the decomposition point of any of the ingredients (e.g., the additives described above, with the exception of some branching agents) of the polymeric composition. While in heat plasticized condition, the polymeric composition is processed into a desired shape, and subsequently cooled to set the shape and induce crystallization. Such shapes can include, but are not limited to, a fiber, filament, film, sheet, rod, tube, bottle, or other shape. Such processing is performed using any art-known technique, such as, but not limited to, extrusion, injection molding, compression molding, blowing or blow molding (e.g. , blown film, blowing of foam), calendaring, rotational molding, casting (e.g. , cast sheet, cast film), or thermoforming.

[0122] Thermoforming is a process that uses films or sheets of thermoplastic. The polymeric composition is processed into a film or sheet. The sheet of polymer is then placed in an oven and heated. When soft enough to be formed it is transferred to a mold and formed into a shape.

[0123] During thermoforming, when the softening point of a semi-crystalline polymer is reached, the polymer sheet begins to sag. The window between softening and droop is usually narrow. It can therefore be difficult to move the softened polymer sheet to the mold quickly enough.

[0124] Branching the polymer can be used to increase the melt strength of the polymer so that the sheet is more readily processed and maintains its structural integrity. Measuring the sag of a sample piece of polymer when it is heated is therefore a way to measure the relative size of this processing window for thermoforming.

[0125] The compositions described herein can be processed into films of varying thickness, for example, films of uniform thickness ranging from 1 to 200 microns, for example, 10 to 75 microns, 75 to 150 microns, or from 50 to 100 microns. Film layers can additionally be stacked to form multilayer films of the same or varying thicknesses or compositions of the same or varying compositions. For example, a film can comprise two, three, four or more layers, where the layers can include one or more layers of a composition or compositions of the invention combined with other polymer layers, such as PHA layers, or other thermoplastic polymer layers, e.g., PLA layers and the like.

1099421.1 [0126] In certain aspects, the film sheets are combined to form a laminate. The laminate can be 1 to 15 layers, for example 2 layers, 3 layers, 4 layers or 5 layers, 6 layers, 7 layers, 8 layers, 10 layers, 11 layers, 12 layers, 13 layers, 14 layers or 15 layers. The overall size of the laminate is about 10 microns to about 100 microns, for example 10-50 microns, 20-60 microns, 25-75 microns. Each individual layer can be about 1 to about 2 microns, for example about 1 to about 5 micron, about 2 to about 4 microns, about 2 to about 5 microns. For each laminate, at least one layer is a composition of the invention. In certain embodiments, the compositions of the invention comprise more than one layer, for example two, three, four or more.

[0127] Blow molding, which is similar to thermoforming and is used to produce "deep draw" products such as bottles and similar products with deep interiors, also benefits from the increased elasticity and melt strength and reduced sag of the polymer compositions described herein.

[0128] Articles made from the compositions can be annealed according to any of the methods disclosed in International Publication No. WO 2010/008445, which was published in English on January 21, 2010, and designated the United States, and is titled "Branched PHA Compositions, Methods For Their Production, And Use In Applications," which was filed in English and designated the United States. This application is incorporated by reference herein in its entirety.

[0129] As disclosed herein, "annealing" and "heat treatment" means a treatment where the polymer composition that is processed to a product in nonliquid form is subsequently (i.e. , after the film is formed) heated for a period of time. This has been found to provide surprising and unexpected properties of puncture toughness and tear resistance in the films comprising the compositions of the invention. Preferably the flat film is heated to about 80°C to about 140°C for about 5 seconds to about 90 minutes, more preferably to about 90°C to about 130°C for about 10 minutes to about 70 minutes, and most preferably to about 110°C to about 125°C for about 15 minutes to about 60 minutes.

[0130] The compositions described herein are provided in any suitable form convenient for an intended application. For example, the composition is provided in pellet for subsequent production of films, coatings, moldings or other articles.

[0131] The polymeric compositions of the present invention can be used to create, without limitation, a wide variety of useful products, e.g. , automotive, consumer durable, consumer disposable, construction, electrical, medical, and packaging products. For instance, the polymeric compositions can be used to make, without limitation, films (e.g. , packaging films,

1099421.1 agricultural film, mulch film, erosion control, hay bale wrap, slit film, food wrap, pallet wrap, protective automobile and appliance wrap, etc.), bags (e.g. , trash bags, grocery bags, food bags, compost bags, etc.), hygiene articles (e.g., diapers, feminine hygiene products, incontinence products, disposable wipes, etc.), coatings for pelleted products (e.g., pelleted fertilizer, herbicides, pesticides, seeds, etc.), packaging (including, but not limited to, packaging and containers for food and beverage products, cosmetic products, detergents and cleaning products, personal care products, pharmaceutical and wellness products, etc.), golf tees, caps and closures, agricultural supports and stakes, paper and board coatings (e.g., for cups, plates, boxes, etc.), thermoformed products (e.g. , trays, containers, yoghurt pots, plant pots, noodle bowls, moldings, etc.), housings (e.g. , for electronics items, e.g. , cell phones, PDA cases, music player cases, computer cases, printers, calculators, LCD projectors, connectors, chip trays, circuit breakers, plugs, and the like), wire and cable products (including, but not limited to, wire, cable and coatings for wire and cable for vehicles, cars, trucks, airplanes, aerospace, construction, military, telecommunication, utility power, alternative energy, and electronics), industrial products (such as, but not limited to, containers, bottles, drums, materials handling, gears, bearings, gaskets and seals, valves, wind turbines, and safety equipment), products for transportation (such as, but not limited to, automotive aftermarket parts, bumpers, window seals, instrument panels, consoles, under hood electrical parts, and engine covers), appliances and appliance parts (such as, but not limited to, refrigerators, freezers, washers, dryers, toasters, blenders, vacuum cleaners, coffee makers, and mixers), articles for use in building and construction (such as, but not limited to, fences, decks and rails, floors, floor covering, pipes and fittings, siding, trim, windows, doors, molding, and wall coverings), consumer goods and parts for consumer goods (such as, but not limited to, power hand tools, rakes^ shovels, lawn mowers, shoes, boots, golf clubs, fishing poles, and watercraft), healthcare equipment (including, but not limited to, wheelchairs, beds, testing equipment, analyzers, labware, ostomy, IV sets, wound care, drug delivery, inhalers, and packaging). In short, the polymeric products described herein can be used to make the items currently made from conventional petroleum-based polymers.

[0132] The specific examples below are to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever. Without further elaboration, it is believed that one skilled in the art can, based on the description herein, utilize the present

1099421.1 invention to its fullest extent. All publications cited herein are hereby incorporated by reference in their entirety.

EXAMPLES

Experimental Methods

Measurement of Melt Strength (C) by Torsional Rheometry

[0133] Melt strength, G', was measured using oscillatory torsional rheology. The

measurements were performed using a TA Instruments AR2000 rheometer employing strain amplitude of 1%. First, pellets (or powder) were molded into 25 mm diameter discs that were about 1200 microns in thickness. The disc specimens were molded in a compression molder set at about 165-177°C, with the molding time of about 30 seconds. These molded discs were then placed in between the 25 mm parallel plates of the AR2000 rheometer, equilibrated at 185°C, and subsequently cooled to 160°C for the frequency sweep test. A gap of 800-900 microns was used, depending on the normal forces exerted by the polymer. The melt density of PHB was determined to be about 1.10 g/cm³ at 160°C; this value was used in all the calculations.

[0134] Specifically, the specimen disc is placed between the platens of the parallel plate rheometer set at 185°C. After the final gap is attained, excess material from the sides of the platens is scraped. The specimen is then cooled to 160°C where the frequency scan (from 625 rad/s to 0.10 rad/s) is then performed; frequencies lower than 0.1 rad/s are avoided because of considerable degradation over the long time it takes for these lower frequency measurements. The specimen loading, gap adjustment and excess trimming, all carried out with the platens set at 185°C, takes about 2 ½ minutes. This is controlled to within ± 10 seconds to minimize variability and sample degradation. Cooling from 180°C to 160°C (test temperature) is accomplished in about four minutes. Exposure to 180°C ensures a completely molten polymer, while testing at 160°C ensures minimal degradation during measurement.

[0135] During the frequency sweep performed at 160°C, the following data are collected as a function of measurement frequency: |n*| or complex viscosity, G' or elastic modulus (elastic or solid-like contribution to the viscosity) and G" or loss modulus (viscous or liquid-like contribution to the viscosity). For purposes of simplicity, we will use G' measured at an imposed frequency of 0.25 rad/s as a measure of "melt strength". Higher G' translates to higher melt strength.

1099421.1 Measurement of Melt Viscosity, Melt Stability and Die Swell by Capillary Rheometry

[0136] The melt viscosity and melt stability were measured by performing steady shear experiments at 180°C, 195°C or 200°C using a Kayness Galaxy V Capillary Rheometer. The die employed in the above capillary measurements was about 1.0 mm in diameter and about 30 mm in length. The capillary rheometer is a controlled shear rate device, and was operated at three shear rates (1,000 sec^"1, 100 sec^"1, and 10 sec^"1), repeated three times, for a total of nine (9) data points collected over 17 minutes. The pellets (~ 10 grams) were preheated at 180°C, 195°C or 200°C for 240 seconds (4 minutes) before the start of the test. The nine test data points are collected without any delay between them.

[0137] Because PHB copolymers undergo chain scission reactions in the melt that lead to a continuous decrease in melt viscosity as a function of time, the above test protocol generates data as shown in WO 2010/008445, incorporated by reference in its entirety.

[0138] When log (Apparent Viscosity) is plotted as a function of time, a systematic decrease in viscosity is evident; this trend is also noted to be quite linear. The slope of the "Apparent Viscosity Versus Time" is an indication of melt stability (according to ASTM D3835). In the results below, this slope for data collected was used at a shear rate of 100 s-1 as an indication of melt stability. The lower the value of the slope, the better the melt stability.

[0139] The die swell at 190°C was measured using the same capillary rheometer equipment described above. However, a laser detector was positioned at the outlet of the capillary die to measure the expansion of the polymer strand as it exited the die. The percent die swell was calculated as the ratio of the polymer strand diameter to the die diameter x 100%. The percent die swell reported in the following examples was determined by first drying the PHA pellets at 75°C for 4 hrs in a vacuum oven (with at least 25 in. Hg vacuum). A die with a 0.079 in.

diameter and L/D = 15/1 was attached to the capillary rheometer and then the barrel of the capillary rheometer was heated to 190°C. Dry pellets (9-1 lg) were then packed in the capillary barrel and a steel piston inserted into the barrel. After 120 sec, the piston was started and the melt extruded through the die. The die swell was then measured versus time and the steady state value reported.

1099421.1 _

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Measurement of the Mechanical Properties of Injection Molded Articles.

[0140] Tensile properties of injection molded articles were measured according to ASTM D638-03.

[0141] Flexural properties of injection molded articles were measured according to ASTM D790-03.

[0142] Notched Izod properties of injection molded articles were measured according to ASTM D256-06.

Analysis ofPHA by Gel Permeation Chromatography (GPC)

[0143] Molecular weight of PHA is estimated by Gel Permeation Chromatography using a Waters Alliance HPLC System equipped with a refractive index detector. The column set is a series of three PLGel 10 μιτι Mixed-B (Polymer Labs, Amherst, MA) columns with chloroform as mobile phase pumped at 1 ml/min. The column set is calibrated with narrow distribution polystyrene standards. The PHA sample is dissolved in chloroform at a concentration of 2.0 mg/ml at 60C. The sample is filtered with a 0.2 μηι Teflon syringe filter. A 50 μ-liter injection volume is used for the analysis. The chromatogram is analyzed with Waters Empower GPC Analysis software. Molecular weights are reported as polystyrene equivalent molecular weights.

Materials

[0144] Four different biobased PHA resin materials were blended and evaluated with various carbodiimides. The four PHA resins' ID and composition were as follows:

PHA A: P3HB Homopolymer

PHA B: Blend of 55-65% P3HB and 35-45% P3HB-4HB copolymer with 8-14% 4HB by weight

PHA C: Blend of 17-23% P3HB and 77-83% P3HB-4HB copolymer with 8-14% 4HB by weight

PHA D: Blend of 34-38% P3HB, 22-26% P3HB-4HB copolymer with 8-14% 4HB by weight and 38-42% P3HB-4HB copolymer with 25-33% 4HB by weight.

[0145] The carbodiimide compounds used in the formulation examples included

STABAXOL^® 1L, a monomeric carbodiimide, STABAXOL^® P with a Tm=60-90°C, Mw= 3000-4000g/mole and %N=C=N of 13%, and STABAXOL^® P400 with a Tm=130°C,

1099421.1 Mw=20,000g/mole and %N=C=N of 13.5% (R ein Chemie Corp.). Both of the latter two compounds are polymeric 2,6-diisopropylphenyl type carbodiimides. To compare the results obtained with the carbodiimides, formulation samples were also prepared with JONCRYL® ADR 4368 CS (BASF Corp.) which is an epoxy functional styrene-acrylic copolymer. Other additives included in the example formulations included the citrate ester plasticizer

CITROFLEX® A4 (Vertellus Specialties Inc.), peroxide branching agent (Akzo Nobel)

TRIGONOX® 101 (2,5-di(tert-butylperoxy)hexane), 117 (tert-butylperoxy-2-ethylhexyl carbonate) and dicumyl peroxide, PE3A and SR444 pentaerythritol acrylate co-agents

(Sartomer), diethyleneglycol diacrylate co-agent (Polysciences), zinc stearate catalyst for co- agent reaction, Lenapy glycerol monostearate (GMS) processing aid (Monson Companies Inc.) , MULTIFEX-MM® calcium carbonate and FLEXTALC® 610D-10 talc filler (Specialty

Minerals), VERTEX® 60 HST magnesium hydroxide flame retardant (Huber Engineered Materials), ACRAWAX® amide wax release agent (IMS Company), TINUVIN® 234 and 326 benzotriazole UV absorbers (CIBA), OCF 3183 glass fiber (Owens Corning) and nucleating agent masterbatches designated Nuc. MB #1 and #2 which were composed of cyanuric acid and boron nitride respectively compounded at a rate of 33% (by weight) into a base PHA resin of 3- hydroxybutanoic acid and 4-hydroxybutanoic acid, and pelleted. Also a nucleant masterbatch designated Nuc. MB #3 which was composed of cyanuric acid suspended in CITROFLEX® A4 at a loading level of 33% by weight.

Example 1: Effect of Carbodiimide on Melt Stability, Melt Viscosity and Die Swell in Reprocessed PHA A Compounded Pellets

[0146] In this example, compounded pellets of the following composition (percent by weight) were prepared: 94% PHA A, 3% of Nuc. MB #2, 2.72% CITROFLEX^® A4, 0.17% of TRIGONOX^® 101 and 0.1 1% of PE3A. The compounded pellets were dried at 80°C for 8-24hrs and then dry blended with 1% of JONCRYL^® (Formulation 1), 1% JONCRYL^® /0.2% zinc stearate (Formulation 2) or 1% of STABAXOL^® P400 (Formulation 3). After dry blending, the pellets were reprocessed on a 16mm twin screw counter-rotating Prism TSE extruder, under the following processing conditions (feed zone to die): 170°C / 171°C / 173°C / 175°C / 175°C / 177°C / 177°C / 177°C / 177°C / 177°C at a screw speed of 250 rpm. A control sample was also

1099421.1 included with the formulation samples which did not have JONCRYL or STABAXOL added during the reprocessing. The melt viscosity, melt stability and die swell were then measured on the control and each formulation as shown in Table 1.

Table 1: Affect of JONCRYL^® and STABAXOL^® P400 on the Melt Strength Retention of Reprocessed PHA A Compounded Pellets.

Formulation (wt %) Control 1 2 3

Compounded PHA A^T pellets* 100 99 98.8 99

JONCRYL^® ADR-4368CS 1 1

Zinc Stearate 0.2

STABAXOL^® P400 1

Total 100 100 100 100

Melt Properties

G', 185°C, pressed at 166°C

360 2720 3217

(Pa)

G', 185°C (Pa) 278 910

% Die Swell (195°C) 179 205 218

Melt Viscosity - 3 min (Pa.s) 984 2430 2510

Melt Stability (min ¹) -0.2351 -0.1816 -0.1127

% Die Swell (200°C) 176 226

Melt Viscosity - 3 min (Pa.s) 604 933

Melt Stability (min ¹) -0.3513 -0.2711

†PHA A: pure P3HB

*94% PHA A, 3% of Nuc. MB #2, 2.72% CITROFLEX^® A4, 0.17% of TR1GONOX^® 101 and 0.11% of PE3 A

[0147] Based on this data it can be concluded that the addition of the JONCRYL /zinc stearate combination was the best at improving the melt strength (G'), melt viscosity and melt stability properties of the compounded pellets. The addition of JONCRYL^® by itself significantly improved these properties as well. The zinc stearate is considered to function as a catalyst for the reaction between carboxylic acid end groups of poly-3-hydroxybutyrate and the epoxy groups of JONCRYL^® and this is likely the reason for the observed JONCRYL^®/stearate performance improvement. The STABAXOL^® P400 did not show the same level of improvement to the melt properties as the formulations containing the JONCRYL^® additives. However, the melt elasticity (die swell) was shown to improve more significantly with the addition of STABAXOL^® P400 than the JONCRYL^® or the JONCRYL^®/zinc stearate blend.

1099421.1 Example 2: Effect of Carbodiimide on Melt Stability, Melt Viscosity and Die Swell in Reprocessed PHA A Compounded Pellets

[0148] This example is similar to Example 1, however the peroxide had been changed to Dicup (dicumyl peroxide) and this co-agent was left out of the formulation with PHA A.

Compounded pellets of the following composition (percent by weight) were prepared: 94.3% PHA A, 2.8% of Nuc. MB #2, 2.5% CITROFLEX^® A4, 0.3% dicumyl peroxide. The

compounded pellets were dried at 80°C for 8-24 hrs and dry blended with either 1% of

JONCRYL^® (Formulation 4), 1% JONCRYL^® /0.2% zinc stearate (Formulation 5) or 1% of STABAXOL^® P400 (Formulation 6). After dry blending, the pellets were reprocessed using a 16mm twin screw counter-rotating Prism TSE extruder under the following processing conditions (feed zone to die): 157°C / 159°C / 160°C / 162°C / 164°C / 164°C / 166°C / 166°C / 166°C / 167°C at 250 rpm screw speed. A control sample was also included with the formulation samples which did not have JONCRYL^® or STABAXOL^® added prior to reprocessing. The melt viscosity, melt stability and die swell were then measured on the control and each formulation as shown in Table 2.

Table 2: Effect of JONCRYL^® and STABAXOL^® P400 on the Melt Strength Retention of Reprocessed PHA A Compounded Pellets.

Formulation (wt %) Control 4 5 6

Compounded PHA A^† pellets* 100 99 98.8 99

JONCRYL^® ADR-4368CS 1 1

STABAXOL^® P400 1

Zinc Stearate 0.2

Total 100 100 100 100

Melt Properties

Tm (°C) 183.9 184.4 183.3 183.9

G\ 185C (Pa) 165 904 1306 859

% Die swell (195°C) 178 195 234 215

Melt Viscosity - 3min (Pa.s) 921 1379 1643 1407

Melt Stability (min^"1) -0.2242 -0.2216 -0.1284 -0.1919

† PHA A: pure P3HB

*94% PHA A, 3% of Nuc. MB #2, 2.72% CITROFLEX^® A4, 0.17% of TRIGONOX^® 101 and 0.11% of PE3A

1099421.1 [0149] The conclusions from the data shown in Table 2 are the very similar to those found in Example 1, e.g., the JONCRYL^® /zinc stearate additive was the most effective in recovering the melt strength, melt viscosity and melt stability properties of the compounded PHA A pellets. However, in this the case the formulation with the JONCRYL^® /zinc stearate also had the highest melt elasticity (% die swell).

Example 3: Effect of Carbodiimide on Melt Stability and Molecular Weight Retention in PHA B

[0150] In this example, a PHA B resin was compounded with 0.4-1.0% by weight

STABAXOL^® P and the effect on the melt stability and molecular weight retention was measured. A control with no STABAXOL^® P was also prepared and analyzed. Along with the STABAXOL^® P, Nuc. MB #1 was also compounded into the PHA B resin at 3% by weight. The compounding was carried out in a Brabender twin screw extruder with the temperature profile 185°C/176°C/170°C with a screw speed of 50rpm. The melt temperature was 176°C and the melt pressure 310psi. Table 3 shows the results:

Table 3: Effect of Carbodiimide on the Melt Stability and Molecular Weight Retention of PHA B Resin.

Formulation (wt %) Control 7 8 9

PHA B* Resin 97 96 96.3 96.6

Nuc. MB #1 3 3 3 3

STABAXOL^® P 1 0.7 0.4

Total 100 100 100 100

Melt Properties

Melt Stability (min^"1) -0.0327 -0.0394 -0.0228 -0.0494

Melt Viscosity - 5 min (Pa

s) 1327 1 194 1162 1346

M_w 382284 41 1614 392590 387959

*PHA B: Blend of 55-65% P3HB and 35-45% P3HB-4HB copolymer with 8-14% 4HB by weight

1099421.1 [0151] Addition of STABAXOL P to PHA B resin showed some improvement in M_w with increasing concentration but either no improvement or marginal improvement in melt viscosity and melt stability.

Example 4: Effect of Carbodiimide on Melt Strength for Reprocessed PHA C Pellets

[0152] In this example, PHA C resin with higher percent 4HB content was compounded into pellets using a Leistriz TSE counter-rotating twin screw extruder. The composition of the pellets (wt %) was as follows: 95% PHA C, 3% Nuc.MB #1, 1.8% CITROFLEX^® A4 and 0.2% Trignox 117. Compounding was carried out at temperatures (feed zone to die) of 175°C / 175°C / 175°C / 175°C / 170°C / 170°C / 170°C / 170°C / 180°C / 180°C at a screw speed of lOOrpm. Prior to reprocessing, the pellets were dried at 80°C for 8-24hrs. The dried pellets were then dry blended with either 1% by wt. STABAXOL^® P400 or 1% by wt. JONCRYL^® ADR-4368CS and injection molded using a Roboshot injection molder at temperatures (front, middle, nozzle, rear, mold) 175°C / 170°C / 165°C / 165°C / 60°C. Clamp pressure was 110,000psi, back pressure 500psi, injection speed 0.5 inch/s and lOOrpm screw speed. Control pellets with no

STABAXOL^® or JONCRYL^® added were also injection molded and the melt strength measured. Table 4 shows the formulations as well as the results for these injection molded pellets.

Table 4: Effect of STABAXOL P400 on the Melt Strength of Reprocessed PHA C

Compounded Pellets.

Formulation (wt %) Control 10 11

Compounded^T PHA C' 100

pellets 99 99

JONCRYL^® ADR-4388CS 1

STABAXOL^® P400 1

Total 100 100 100

Melt Properties

G' 180°C (Pa) 256 379 1254

† 95% PHA C, 3% Nuc.MB #1, 1.8% CITROFLEX^® A4 and 0.2% TRIGONOX^® 117 * Blend of 17-23% P3HB and 77-83% P3HB-4HB copolymer with 8-14% 4HB by weight

1099421.1 [0153] The data shown in Table 4 indicates that with the addition of 1 % STABAXOL P400, the melt strength of the PHA C compounded pellets increased five times over the Control sample. In contrast, the PHA C pellets with JONCRYL^® added showed only a modest increase in melt strength (1.5 times).

Example 5: Effect of Carbodiimide on Melt Stability, Melt Viscosity and Molecular Weight Retention of PHA D Resin

[0154] In this example, PHA D resin was mixed with 0.7% by wt. STABAXOL^® P and the effect on the melt stability and molecular weight retention was measured. A control with no STABAXOL^® P was also prepared and analyzed. Nucleant master batch #1 was also added to all samples at 3% by wt. The compounding was carried out with a Brabender counter-rotating, twin screw extruder using a temperature profile of 180°C / 175°C / 170°C with a screw speed of 50 rpm. Table 5 summarizes the results found.

Table 5: Effect of Carbodiimide on the Melt Stability, Melt Viscosity and Molecular Weight Retention of PHA D Resin

Formulation (wt %) Control 12

PHA D* Resin 97 96.3

Nuc. MB #1 3 3

STABAXOL^® P 0.7

Total 100 100

Melt Properties

Melt Stability (min ¹) -0.217 -0.093

Melt Viscosity - 5 min (Pa s) 456 1713

M_w 290615 416582

* Blend of 34-38% P3HB, 22-26% P3HB-4HB copolymer with 8-14% 4HB by weight and 38-42% P3HB-4HB copolymer with 25-33% 4HB by weight

[0155] The data in Table 5 shows that the addition of 0.7% by wt. STABAXOL^® P to PHA D resin improved the melt stability by a factor of 2.3 and melt viscosity by a factor of 3.8. The improvement in these melt properties is due to the better molecular weight retention as shown with the M_w values. This data is in contrast to that shown in Example 3 where addition of 0.7% STABAXOL^® P showed, slight improvement in M_w and marginal improvement in the melt

1099421.1 stability. The main difference between PHA B and D is the total percent 4HB content of these resins. PHA D has 3-4 times more 4HB as PHA B resin. The data suggests that STABAXOL^® is better at maintaining the melt properties for PHA resins with higher percent 4HB content during processing compared to JONCRYL^® which appears better at maintaining melt properties for PHA resins with higher P3HB content. This applies to Poly(3HB-co-4HB) resins that are being reprocessed or recycled multiple times.

Example 6: Effect of Carbodiimide on Melt Strength of Reprocessed PHA D Compounded Pellets

[0156] In this example, compounded pellets of the following compositions (percent by weight) were prepared from PHA D having high percent 4HB content: Pellets #1 - 95% PHA D, 3% of Nuc. MB #1, 1.94% CITROFLEX^® A4, 0.06% Dicup; Pellets #2 -95% PHA D, 3% of Nuc. MB #1, 1.72% CITROFLEX^® A4, 0.1% of TRIGONOX^® 117 and 0.18% of PE3A. The compounded pellets were dried at 80°C for 8-24hrs and then dry blended with 1% of

JONCRYL^® (Formulations 13, 15) or 1% of STABAXOL^® P400 (Formulations 14, 16). After dry blending, the pellets were reprocessed on a Leistriz twin screw counter-rotating TSE extruder, under the following processing conditions (feed zone to die): 175°C / 175°C / 175°C / 175°C / 170°C / 170°C / 170°C / 170°C / 180°C / 180°C at a screw speed of 100 rpm. Control samples (#1 and #2) were also included with the formulation samples which did not have JONCRYL^® or STABAXOL^® added during the reprocessing. The melt strength was then measured on the control and each formulation as shown in Table 6.

1099421.1 Table 6: Effect of STABAXOL P400 on the Melt Strength of Reprocessed PHA D Compounded Pellets.

Control

Formulation (wt %) #1 Control #2 13 14 15 16

Compounded^† PHA D^* pellets

#1 100 99 99

Compounded^†† PHA D* pellets

#2 100 99 99

JONCRYL^® ADR-4388CS 1 1

STABAXOL^® P400 1 1

Total 100 100 100 100 100 100

Melt Properties

G\ 180°C (Pa) 95 67 117 239 119 245

† P rellets #1 - 95% PHA D, 3% of\ Nτuc. MB #1, 1.94% CITROFLE-<xX<S A4, 0.06% Dicup

†^† Pellets #2 -95% PHA D, 3% of Nuc. MB #1, 1.72% CITROFLEX^® A4, 0.1% of TRIGONOX^® 117 0.18% of PE3A

* Blend of 34-38% P3HB, 22-26% P3HB-4HB copolymer with 8-14% 4HB by weight and 38-42%

P3HB-4HB copolymer with 25-33% 4HB by weight

[0157] The data in Table 6 shows that the improvement in melt strength for reprocessed PHA D compounded pellets was more significant when STABAXOL^® P400 was added versus the JONCRYL^® ADR-4388CS additive. This is in contrast to the results from Example 2 where reprocessed PHA A (0% 4HB) compounded pellets with the additive JONCRYL^® +zinc stearate improved the melt properties more than the STABAXOL^® additive. The results in Table 6 also show the same trend as observed in Example 5 where PHA D resin with high percent 4HB content showed a more significant improvement in melt properties when

STABAXOL^® was added versus JONCRYL^®.

Example 7: Effect of Carbodiimide on Melt Strength, Melt Viscosity, Melt Stability and Die Swell of a Reprocessed 1/1 Blend of PHA B and C Resins in Compounded Pellets

[0158] In this example, compounded pellets of the following composition (percent by weight) were prepared from a 1/1 blend of PHA B and C resins: 42.2% PHA B, 42.2% PHA C, 3.1% of Nuc. MB #2, 1.9% CITROFLEX^® A4, 0.12% T101, 0.08% PE3A, 0.4% GMS and

1099421.1 10% FLEXTALC 610D. The compounded pellets were dried at 80°C for 8-24hrs and then dry blended with 1% of JONCRYL^® (Formulation 17), 1% JONCRYL^® +0.2% zinc stearate (Formulation 18) and 1% of STABAXOL^® P400 (Formulation 19). After dry blending, the pellets were reprocessed on a 16mm Prism twin screw counter-rotating TSE extruder, under the following processing conditions (feed zone to die): 167°C / 169°C / 170°C / 172°C / 174°C / 174°C / 176°C / 176°C / 176°C / 177°C at a screw speed of 250 rpm. A control sample was also included with the formulation samples which did not have JONCRYL^® or STABAXOL^® added during the reprocessing. The melt strength, melt viscosity, melt stability and die swell were then measured on the control and each of the formulations as shown in Table 7.

Table 7: Effect of JONCRYL , JONCRYL /zinc stearate and STABAXOL P400 Additives on the Melt Strength, Melt Viscosity, Melt stability and Die Swell of a Reprocessed 1/1 Blend of PHA B and PHA C Compounded Pellets.

Formulation (wt %) Control 17 18 19

Compounded 1/1 Blend of PHA B and

C^† pellets* 100 99 98.8 99

JONCRYL^® ADR-4368CS 1 1

STABAXOL^® P400 1

Zinc Stearate 0.2

Total 100 100 100 100

Melt Properties

G\ 185C (Pa) 535 1193 1143 2489

% Die swell (200°C) 148 159 166 202

Melt Viscosity - 3min (Pa.s) 726 920 931 1294

Melt Stability (min ¹) -0.2121 -0.1998 -0.2260 -0.095

† PHA B: Blend of 55-65% P3HB and 35-45% P3HB-4HB copolymer with 8-14% 4HB by weight;

*42.2% PHA B, 42.2% PHA C, 3.1% of Nuc. MB #2, 1.9% C1TROFLEX^® A4, 0.12% T101, 0.08% PE3A, 0.4% GMS and 10% FLEXTALC^® 610D

[0159] As shown in Table 7, there was a significant improvement in all of the melt retention properties for the 1/1 blend of PHA B and C resins when STABAXOL^® P400 was used as an additive. Specifically, the melt strength improved 4.7 times over that of the control versus 2.1 times for the JONCRYL^® or JONCRYL^® /zinc stearate additives, Die swell improved 36% for STABAXOL^® versus 7-12% for the JONCRYL^® or JONCRYL^® /zinc stearate additives, and

1099421.1 melt stability improved 55% when STABAXOL was added versus only marginal

improvement when JONCRYL^® or JONCRYL^® /zinc stearate were added. In Example 3 where STABAXOL^® was added to compounded PHA B resin, no improvement in any of the melt retention properties was observed. However there was an overall improvement in the molecular weight retention. In this example when PHA B was blended with PHA C (higher percent 4HB content), addition of STABAXOL^® gave very large improvements in all of the melt properties during reprocessing. This is likely the result of the synergistic effect of the STABAXOL^® with the higher percent 4HB content PHA resin.

Example 8: Effect of Carbodiimide on Melt Strength, Melt Viscosity, Melt Stability and Die Swell of a Reprocessed 1/1 Blend of PHA B and C Resins in Compounded Pellets

Containing No Peroxide Initiator or Co-agent

[0160] In this example, compounded pellets of the following composition (percent by weight) were prepared from a 1/1 blend of PHA B and C resins: 33.8% PHA B, 33.8% PHA C, 2.1% of Nuc. MB #1, 6.7% CITROFLEX^® A4 and 23.6% FLEXTALC^® 610D. The

compounded pellets were dried at 80°C for 8-24hrs and then dry blended with 1% of

JONCRYL^® (Formulation 20), 1% JONCRYL^®+0.2% zinc stearate (Formulation 21) and 1% of STABAXOL^® P400 (Formulation 22). After dry blending, the pellets were reprocessed on a 16mm Prism twin screw counter-rotating TSE extruder, under the following processing conditions (feed zone to die): 167°C / 169°C / 170°C / 172°C / 174°C / 174°C / 176°C / 176°C / 176°C / 177°C at a screw speed of 250 rpm. A control sample was also included with the formulation samples which did not have JONCRYL^® or STABAXOL^® added during the reprocessing. The melt strength, melt viscosity, melt stability and die swell were then measured on the control and each of the formulations as shown in Table 8.

1099421.1 Table 8: Effect of JONCRYL , JONCRYL /zinc stearate and STABAXOL Additives on the Melt Strength, Melt Viscosity. Melt stability and Die Swell of a Reprocessed 1/1 Blend of PHA B and PHA C Compounded Pellets containing no peroxide initiator or co-agent.

Formulation (wt %) Control 20 21 22

Compounded 1/1 Blend of PHA B and

C^† pellets* 100 99 98.8 99

JONCRYL^® ADR-4368CS 1 1

STABAXOL^® P400 1

Zinc Stearate 0.2

Total 100 100 100 100

Melt Properties

G\ 180C (Pa) 57.4 150 108 181

% Die swell (190°C) 91 95 93 93

Melt Viscosity - 3min (Pa.s) 846 1018 973 943

Melt Stability (min ¹) -0.1452 -0.1298 -0.1150 -0.1007

*33.8% PHA B, 33.8% PHA C, 2.1% of Nuc. MB #1, 6.7% CITROFLEX^® A4 and 23.6%

FLEXTALC^® 610D

[0161] The results from Table show that while STABAXOL^® improved melt strength and stability better than JONCRYL^®, JONCRYL^® by itself gave the highest melt viscosity value among the additives during reprocessing of the compounded pellets. This example highlights the unexpected observation that STABAXOL^® appeared to have a synergistic effect with other additives in the compounded pellets. Comparing these results to those from Example 7, without the addition of the peroxide initiator and co-agent, the STABAXOL^® carbodiimide additive did not have as significant an impact on all the melt properties even though it did show

improvements in melt strength and stability.

Example 9: Effect of Carbodiimide on Retention of Mechanical Properties and Molecular Weight in PHA B Resin with Added Flame Retardant

[0162] In this example, the effect of carbodiimide addition on a formulation with PHA B resin and a flame retardant additive were investigated. Compounded pellets were prepared using a Leistriz twin screw, counter rotating TSE extruder under the following processing conditions

1099421.1 (feed zone to die): 175°C / 175°C / 175°C / 175°C / 170°C / 170°C / 170°C / 170°C / 170°C / 180°C at a screw speed of 125rpm. In order to add the STABAXOL® 1L, it was first melted in an oven at 65°C then fed into the extruder. After compounding, the pellets were dried at 80°C for 8-24hrs and extruded into bars using a oboshot injection molder. The conditions for the injection molder were as follows: front/middle/rear/nozzle/mold temperatures were 165°C / 165°C / 160°C / 160°C / 60°C, clamp pressure 110,000psi, back pressure 850psi, screw speed 150rpm. After injection molding, the bars were again dried at 50°C for 48hrs prior to testing. Table 9 gives the composition of the formulations tested as well as the results for the mechanical properties and molecular weight of the molded bars. Two control samples were included in the data set: Control #1 with no flame retardant and Control #2 with 33% by weight added flame retardant.

[0163] Table 9 shows that with no flame retardant added (Control #1), the compounded PHA B has good M_w and mechanical properties. With the addition of JONCRYL^® (Formulation 28), the final molecular weight and flexural strength increased. When the flame retardant was added to the composition (Control #2), the molecular weight after processing dropped by 60% compared to Control #1 , the impact strength decreased. The flame retardant therefore was shown to have a significantly negative impact on the PHA B resin properties. When JONCRYL^® was added to the PHA B+flame retardant (Formulations 26 and 27), the molecular weight still decreased by 70%. Except for the flexural strength, the mechanical properties did not appear to improve very much compared to Control #2. When the carbodiimide compounds were added (STABAXOL^® 1L, P and P400), the molecular weight retention was greatly improved in the presence of the flame retardant. The flexural modulus was also shown to improve especially for Formulation 25 (with 1% STABAXOL^® P) while maintaining good impact properties. The data shows again that STABAXOL^® can have a synergistic effect with other additives in the PHA resin even when one of the additives initially was shown to impart very poor properties to the resin.

1099421.1 Table 9: Effect of JONCRYL and STABAXOL on the Mechanical Properties and Molecular Weight of PHA B Pellets with Flame Retardant

† PHA B: Blend of 55-65% P3HB and 35-45% P3HB-4HB copolymer with 8-14% 4HB by weight

Example 10: Effect of Carbodiimide on Hydrolysis Resistance and Retention of Mechanical Properties in PHA B Resin

[0164] For this example, the synergistic effects of carbodiimide additives with benzotriazole UV blockers for hydrolysis resistance in PHA B resin is shown. Compounded pellets were prepared using a Leistriz twin screw, counter rotating TSE extruder under the following processing conditions (feed zone to die): 175°C / 175°C / 175°C / 175°C / 170°C / 170°C / 170°C / 170°C / 170°C / 180°C at a screw speed of 125rpm. After compounding, the pellets were dried at 80°C for 8-24hrs and extruded into bars using a Roboshot injection molder. The conditions for the injection molder were as follows: front/middle/rear/nozzle/mold temperatures were 165°C / 165°C / 160°C / 160°C / 60°C, clamp pressure 110,000psi, back pressure 850psi, screw speed 150rpm. After injection molding, the bars were again dried at 50°C for 48hrs prior to testing. To test the hydrolysis resistance, bars were autoclaved at 120°C for 20 minutes, then cooled at room temperature and dried. The surface was then examined visually to qualitatively assess the level of surface spotting due to hydrolysis. These autoclaved bars were also tested for

1099421.1 tensile, flexural and impact mechanical properties. Table 10 gives the composition of the formulations tested as well as the results for the mechanical properties and hydrolysis resistance for the molded bars.

[0165] The results in Table 10 indicate that addition of STABAXOL^® carbodiimide and TINUVIN^® UV absorbers to PHA B resin appeared to have a synergistic effect in minimizing damage due to hydrolysis. The combination of STABAXOL^® P with TINUVIN^® 326 gave the best protection from hydrolysis as shown by the improvement in Tensile elongation and Flexural strength as well as Notched Izod Impact Strength. The surface appearance of the bar after exposure to the autoclave conditions was also better where only very few small water spots were observed over the surface as compared to the Control sample. Some improvement in hydrolysis resistance was observed when STABAXOL^® P was used as an additive by itself in PHA B resin.

Table 10: Effect of Carbodiimide and UV stabilizers on Hydrolysis Resistance of PHA B Resin.

1099421.1 Notched Izod Impact Before

Strength (ft-lb/in) autoclaving 0.516 0.482 0.477 0.496

After autoclaving 0.515 0.493 0.476 0.523

Many Fewer Few Few large medium small small

Surface Appearance After autoclaving spots spots spots spots

Example 11: Method for Making PHA/Carbodiimide Masterbatch

[0166] In certain PHA processing applications, it is desirable to have the carbodiimide predispersed in a PHA resin at a relatively high concentration in order to facilitate the compounding and dispersal of the carbodiimides into the final PHA formulation. Compounds that are added to polymers in this way are called Masterbatches due to the fact that they are in the Masterbatch at high concentration and are usually the only additive or one of a few additives present. This example describes the formulation and processing conditions necessary to create a carbodiimide/PHA Masterbatch.

[0167] PHA resins for preparing the Masterbatch would include blends of P3HB

homopolymer and P3HB-co-4HB copolymers. The blends would have the following

composition: PHA A - A blend of 55-65% P3HB and 35-45% P3HB-4HB copolymer with 8- 14% 4HB by weight; PHA B: A blend of 15-25% P3HB, 75-85% P3HB-4HB copolymer with 8- 14% 4HB by weight. PHA C -a blend of 34-38% P3HB, 22-26% P3HB-P4HB with 8-14% 4HB by weight and 38-42% P3HB-co-4HB with 25-33% 4HB by weight.

[0168] A typical formulation for the carbodiimides Masterbatch would be as follows: 15- 25% by wt. of PHA A, 75-85% by PHA B, 0-1% nucleating agent and 10-40% by wt.

carbodiimide.

[0169] Another typical formulation would be 59-89% by weight of PHAC, 0-1%% nucleating agent and 10-40%) carbodiimide.

[0170] Another typical formulation would be 59 to 89% by weight of PHA B, 0-1% nucleating agent and 10-40%) carbodiimide.

[0171] Prior to preparing the Masterbatch, the PHA resin blends are dried at 80°C for 24 hours in a vacuum oven. After drying they can then be processed in a Leistritz 27mm twin screw extruder or equivalent under the following conditions (feed to die barrel temperatures) 172°C /

1099421.1 172°C / 172°C / 172°C / 167°C / 167°C / 167°C / 167°C / 177°C / 177°C at a screw speed of lOOrpm and total feed rate of 60 lb/hr.

Example 12: Effect of Carbodiimide on the Melt Strength, Melt Viscosity, Melt Stability of a Reprocessed P(3HB-co-3HV) Resin in Compounded Pellets

[0172] In this example, compounded pellets of the following composition (percent by weight) were prepared: 93% Biopol 12% PHBV resin (poly(3-hydroxybutyrate-co-3- hydroxyvalerate), 2% boron nitride, and 5% CITROFLEX^® A4. The compounded pellets were dried at 80°C for 8-24hrs and then dry blended with 1% of JONCRYL^® (Formulation 32) and 1%) of STABAXOL^® P400 (Formulation 33). After dry blending, the pellets were reprocessed on a 16mm Prism twin screw counter-rotating TSE extruder, under the following processing conditions (feed zone to die): 157°C / 159°C / 160°C / 162°C / 164°C / 164°C / 166°C / 166°C / 166°C / 167°C at a screw speed of 250 rpm. A control sample was also included with the formulation samples which did not have JONCRYL^® or STABAXOL^® added during the reprocessing. The melt strength, melt viscosity, melt stability and die swell were then measured on the control and each of the formulations as shown in Table 11.

Table 11: Effect of JONCRYL^® and STABAXOL Additives on the Melt Strength, Melt Viscosity and Melt stability of a Reprocessed PHBV resin.

Formulation (wt %) Control 32 33

Compounded Biopol PHBV pellets* 100 99 99

JONCRYL® ADR-4368CS 1

STABAXOL^® P400 1

Total 100 100 100

Melt Properties

G\ 180C (Pa) 1.71 2.17 2.10

Melt Viscosity - 3min (Pa.s) 520 532 682

Melt Stability (min ¹) -0.1364 •0.1462 -0.1233

® . . ,

*Biopol 12% PHBV resin with 2% boron nitride and 5% CITROFLEX* A4 by weig

The results in Table 11 showed that the STABAXOL additive had a greater effect on increasing the melt properties of the previously processed PHBV resin as compared to JONCRYL^® additive similar to what was observed for the higher 4HB containing P3HB-co-4HB resins.

1099421.1 Example 13: Effect of Adding STABAXOL^® on the Melt Strength, Melt Viscosity and Melt Stability of a Reprocessed P(3HB-co-3HH) Resin in Compounded Pellets

[0173] In this example, we tried to initially prepare compounded pellets of the following composition (percent by weight): 97% of a 12% PHH resin (poly(3-hydroxybutyrate-co-3- hydroxyhexanoate) mixed with 3% Nucleation Masterbatch #1 (cyanuric acid in CITROFLEX A4^®). The resin was processed on a 16mm Prism twin screw counter-rotating TSE extruder, under the following processing conditions (feed zone to die): 157°C / 159°C / 160°C / 162°C / 164°C / 164°C / 166°C / 166°C / 166°C / 167°C at a screw speed of 250 rpm. During extrusion, it was observed that the material would not solidify and crystallize in time to form a strand for pelletization. Therefore no reprocessing with STABAXOL^® additive was carried out with this formulation.

Example 14: Effect of High Loadings of Carbodiimide on Melt Strength, Melt Viscosity and Melt Stability of a Reprocessed 1/1 Blend of PHA B and C Resins in Compounded Pellets

[0174] In this example, compounded pellets with high loadings of a carbodiimide were prepared using a 1/1 blend of PHA B and C resins. The composition of the pellets in weight percent were as follows: 33.8% PHA B, 33.8% PHA C, 2.1% of Nuc. MB #1, 6.7%

CITROFLEX^® A4, and 23.6% FLEXTALC^® 610D. The compounded pellets were dried at 80°C for 8-24hrs and then dry blended with 1% and 10% of JONCRYL^® (Formulations 34 and 37), 1% JONCRYL^® +0.2% zinc stearate (Formulation 35) and 1% and 10% STABAXOL^® P400 (Formulations 35 and 38). After dry blending, the pellets were reprocessed on a 16mm Prism twin screw counter-rotating TSE extruder, under the following processing conditions (feed zone to die): 162°C / 164°C / 165°C / 166°C / 168°C / 168°C / 168°C / 168°C / 168°C / 168°C at a screw speed of 250 rpm. A control sample was also included with the formulation samples which did not have JONCRYL^® or STABAXOL^® added during the reprocessing. The melt strength, melt viscosity and melt stability were then measured on the control and each of the formulations as shown in Table 12.

1099421.1 Table 12: Effect of JONCRYL , JONCRYL /zinc stearate and STABAXOL P400

Additives at High Loadings on the Melt Strength, Melt Viscosity and Melt Stability of a Reprocessed 1/1 Blend of PHA B and PHA C Compounded Pellets.

Formulation (wt %) Control 34 35 36 37 38

Compounded 1/1 Blend of PHA B and C^†

pellets* 100 99 98.8 99 90 90

JONCRYL® ADR-4368CS 1 1 10

STABAXOL® P400 1 10

Zinc Stearate 0.2

Total 100 100 100 100 100 100

Melt Properties

G\ 180C (Pa) 49.65 1 1 1.9 88.58 125.6 270 1264

Melt Viscosity - 3min (Pa.s) 3219 4454 3886 4669 5929 11730

Melt Stability (min ¹) -0.0655 -0.042 -0.0513 -0.0599 -0.0124 -0.0335

† PHA B: Blend of 55-65% P3HB and 35-45% P3HB-4HB copolymer with 8-14% 4HB by weight; PHA C:

Blend of 17-23% P3HB and 77-83% P3HB-4HB copolymer with 8-14% 4HB by weight

*33.8% PHA B, 33.8% PHA C, 2.1% of Nuc. MB #1, 6.7% CITROFLEX^® A4 and 23.6% FLEXTALC^®

610D

[0175] The data in Table 12 shows again that STABAXOL^® P400 has a greater effect on the melt properties than comparable levels of JONCRYL^® or JONCRYL^®+zinc stearate. As the weight percent of STABAXOL^® P400 increased to 10%, the melt strength increased by a factor of 26 while the melt viscosity increased by a factor of 3.6 as compared to the Control sample. A comparable increase in the weight percent JONCRYL^® to 10% only showed an increase in melt strength by a factor of 5.4 and an increase in melt viscosity by a factor of 1.8 as compared to the Control. The melt stability at all loading appeared to be slightly better for the pellets with JONCRYL^® as compared to the pellets with STABAXOL^®.

Example 15: Method of making PHA/JONCRYL^® Masterbatch:

[0176] PHA resins for preparing the Masterbatch would include blends of P3HB

homopolymer and P3HB-co-4HB copolymers. The blends would have the following

composition: PHA A - a blend of 55-65%) P3HB and 35-45% P3HB-4HB copolymer with 8-14% 4HB by weight; PHA B - a blend of 15-25% P3HB, 75-85% P3HB-4HB copolymer with 8-14% 4HB by weight; PHA C is a blend of 34-38% P3HB, 22-26% P3HB-P4HB with 8-14% 4HB by weight and 38-42% P3HB-co-4HB with 25-33% 4HB by weight.

[0177] A typical formulation for the JONCRYL^® Masterbatch would be as follows: 15-25% by wt. of PHA A, 75-85% of PHA B, 0-1% nucleating agent and 10-40% by wt. JONCRYL^®.

1099421.1 Another typical formulation would be 59 to 89% by weight of PHA C, 0-1% nucleating agent and 10-40% JONCRYL^®.

[0178] Another typical formulation would be 59 to 89% by weight of PHA B, 0-1% nucleating agent and 10-40% JONCRYL^®.

[0179] Other additives to be used with STABAXOL and JONCRYL products as described herein include but are not limited to: CaC0₃: FilmLink 500, EMforce Bio, Multiflex MM, Supercoat

Talcs: Flextalc 1222, Flex Talc 610 D, Optibloc 10, Jetfine 3CA, Jetfme 1H, Jetfine 3CC Lubricants/surfactants: Acrawax-C (Ethylenebistearamide), Acrawax CV, Lenape GMS, Erucamide; Span 80 (Sorbitan monooleate) Plasticizers: Citroflex A4, Paraplex A8600, Paraplex 8654, Plasthall P643, DAP (diallyl phthalate), Peroxides: Trigonox 101, Perkadox BC FF (DICUP), Acrylic co-agents: Sartomer SR231 and Polymers: non PHA thermoplastic polyesters, including but not limited to poly butylene succinate (BIONOLLE 1001MD (Showa), polybutylene adipate terephthalate (PBAT) (BASF Ecoflex F BX 7011) or poly butylene succinate adipate.

[0180] The teachings of all patents, published applications and references cited herein are incorporated by reference in their entirety.

[0181] While this invention has been particularly shown and described with references to example embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.

1099421.1

Claims

What is claimed is:

1. A composition comprising a biobased polyhydroxyalkanoate polymer (PHA) and a chain extender, wherein at least 10 % of the PHA by weight is recyclate PHA, wherein the PHA is not a polymer consisting of 97% of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) having 12% hydroxyhexanoate content or polylactic acid.

2. The composition of claim 1, wherein between about 10% and about 100 % by weight of the PHA is recyclate PHA.

3. The composition of claim 1 , wherein between about 20% and 65% by weight of the PHA is recyclate PHA.

4. The composition of claim 1 , wherein the chain extender is a carbodiimide.

5. The composition of claim 3, wherein the carbodiimide is a polymeric carbodiimide.

6. The composition of claim 3, wherein the carbodiimide is a monomeric carbodiimide.

7. The composition of claim 5, wherein the carbodiimide is a 2,6-diisopropylphenyl type carbodiimide.

8. The composition of claim 4, wherein the weight percent of carbodiimide is between about 0.4 % and about 1.2% of the total composition.

9. The composition of claim 8, wherein the weight percent of carbodiimide is about 1% of the total composition.

10. The composition of claim 1, wherein the composition further comprises a branching

agent.

11. The composition of claim 10, wherein the branching agent is selected from: dicumyl peroxide, t-amyl-2-ethylhexyl peroxycarbonate, l,l-bis(t-butylperoxy)-3,3,5-

1099421.1 trimethylcyclohexane, 2,5-dimethyl-2,5-di(t-butylperoxy) hexane, 2,5-bis(t-butylperoxy)- 2,5-dimethylhexane, 2,5-dimethyl-di(t-butylperoxy)hexyne-3, di-t-butyl peroxide, benzoyl peroxide, di-t-amyl peroxide, t-butyl cumyl peroxide, n-butyl-4,4-bis(t- butylperoxy)valerate, 1 , 1 -di(t-butylperoxy)-3,3 ,5-trimethyl-cyclohexane, 1 , 1 -di(t- butylperoxy)cyclohexane, 1 , 1 -di(t-amylperoxy)-cyclohexane, 2,2-di(t- butylperoxy)butane, ethyl-3 ,3 -di(t-butylperoxy)butyrate, 2,2-di(t-amylperoxy)propane, ethyl-3, 3 -di(t-amylperoxy)butyrate, t-butylperoxy-acetate, t-amylperoxyacetate, t- butylperoxybenzoate, t-amylperoxybenzoate, and di-t-butyldiperoxyphthalate.

12. The composition of any one of claims 1-11, wherein the concentration of branching agent is between 0.001 to 0.5% by weight of the PHA.

13. The composition of any one of the preceding claims, wherein the composition further comprises one or more additives.

14. The composition of any one of the preceding claims, wherein the composition further comprises a nucleating agent.

15. The composition of any one of the preceding claims, wherein the composition further comprises a flame retardant.

16. The composition of any one of the preceding claims, wherein the composition further comprises a co-agent.

17. The composition of any one of the preceding claims, wherein the composition further comprises a UV absorber.

18. The composition of any one of the preceding claims, wherein the composition further comprises a cross-linking agent.

1099421.1 The composition of any one of the preceding claims, wherein, the biobased

polyhydroxyalkanoate polymer is a poly(3-hydroxybutyrate) homopolymer, a poly(3- hydroxybutyrate-co-4-hydroxybutyrate) copolymer, a poly(3-hydroxybutyrate-co-3- hydroxyvalerate) copolymer, a poly(3-hydroxybutyrate-co-5-hydroxyvalerate) copolymer, or a poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) copolymer.

The composition of any one of claims 1-18, wherein the biobased polyhydroxyalkanoate polymer is a poly(3-hydroxybutyrate) homopolymer, a poly(3-hydroxybutyrate-co-4- hydroxybutyrate) with 5% to 15% 4-hydroxybutyrate content, a poly(3-hydroxybutyrate- co-3 -hydroxy valerate) with 5% to 22% 3 -hydroxy valerate content, a poly(3- hydroxybutyrate-co-5-hydroxyvalerate) with 5% to 15% 5 -hydroxy valerate content, or a poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) with 3% to 15% 3-hydroxyhexanoate content.

The composition of any one of claims 1-18, wherein the biobased polyhydroxyalkanoate is a) a poly(3-hydroxybutyrate) homopolymer blended with b) a poly(3-hydroxybutyrate- co-4-hydroxybutyrate); a) a poly(3-hydroxybutyrate) homopolymer blended with b) a poly(3-hydroxybutyrate-co-3-hydroxyvalerate); a) a poly(3-hydroxybutyrate)

homopolymer blended with b) a poly(3-hydroxybutyrate-co-3-hydroxyhexanoate); a) a poly(3-hydroxybutyrate-co-4-hydroxybutyrate) blended with b) a poly(3- hydroxybutyrate-co-3-hydroxyvalerate); a) a poly(3-hydroxybutyrate-co-4- hydroxybutyrate) blended with b) a poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) or a) a poly(3-hydroxybutyrate-co-3 -hydroxy valerate) blended with b) a poly(3- hydroxybutyrate-co-3 -hydroxyhexanoate) .

The composition of any one of claims 1-18, wherein the biobased polyhydroxyalkanoate is a) a poly(3-hydroxybutyrate) homopolymer blended with b) a poly(3-hydroxybutyrate- co-4-hydroxybutyrate) with a 5% to 15% 4-hydroxybutyrate content; a) a poly(3- hydroxybutyrate) homopolymer blended with b) a poly(3-hydroxybutyrate-co-3- hydroxyvalerate) with a 5% to 22% 3 -hydroxy valerate content; a) a poly(3- hydroxybutyrate) homopolymer blended with b) a poly(3-hydroxybutyrate-co-3- hydroxyhexanoate) with a 3% to 15% 3-hydroxyhexanoate content; a) a poly(3- hydroxybutyrate-co-4-hydroxybutyrate) with a 5% to 15% 4-hydroxybutyrate content blended with b) a poly(3-hydroxybutyrate-co-3-hydroxyvalerate) with a 5% to 22% 3- hydroxyvalerate content; a) a poly(3-hydroxybutyrate-co-4-hydroxybutyrate) with 5% to 15%o 4-hydroxybutyrate content blended with b) a poly(3-hydroxybutyrate-co-3- hydroxyhexanoate) with a 3% to 15% 3-hydroxyhexanoate content or a) a poly(3- hydroxybutyrate-co-3-hydroxyvalerate) with a 5% to 22% 3 -hydroxy valerate content blended with b) a poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) with a 3%> to 15% 3- hydroxyhexanoate content.

23. The composition of claim 21 or 22, wherein the biobased polyhydroxyalkanoate is a) a poly(3-hydroxybutyrate) homopolymer blended with b) a poly(3-hydroxybutyrate-co-4- hydroxybutyrate) and the weight of polymer a) is 5% to 95% of the combined weight of polymer a) and polymer b); a) a poly(3-hydroxybutyrate) homopolymer blended with b) a poly(3-hydroxybutyrate-co-3 -hydroxy valerate) and the weight of polymer a) is 5% to 95%) of the combined weight of polymer a) and polymer b); a) a poly(3-hydroxybutyrate) homopolymer blended to with b) a poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) and the weight of polymer a) is 5% to 95% of the combined weight of polymer a) and polymer b); a) a poly(3-hydroxybutyrate-co-4-hydroxybutyrate) blended with b) a poly(3- hydroxybutyrate-co-3-hydroxyvalerate) and the weight of polymer a) is 5% to 95% of the combined weight of polymer a) and polymer b); a) a poly(3-hydroxybutyrate-co-4- hydroxybutyrate) blended with b) a poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) and the weight of polymer a) is 5% to 95% of the combined weight of polymer a) and polymer b); or a) a poly(3-hydroxybutyrate-co-3-hydroxyvalerate) blended with b) a poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) and the weight of polymer a) is 5% to 95% of the combined weight of polymer a) and polymer b).

24. The composition of claim 21 , 22 or 23, wherein the weight of polymer a) is 20 % to 60%) of the combined weight of polymer a) and polymer b) and the weight of polymer b) is 40%) to 80%) of the combined weight of polymer a) and polymer b).

1099421.1

25. The composition of claims 1-18, wherein the biobased polyhydroxyalkanoate is a) poly(3- hydroxybutyrate) homopolymer blended with b) a poly(3-hydroxybutyrate-co-4- hydroxybutyrate) with a 20-50% 4-hydroxybutyrate content; a) a poly(3 -hydroxybutyrate) homopolymer blended with b) a poly(3-hydroxybutyrate-co-5-hydroxyvalerate) with a 20% to 50% 5 -hydroxy valerate content; a) a poly(3 -hydroxybutyrate) homopolymer blended with b) a poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) having a 5%-50% 3- hydroxyhexanoate content; a) poly(3-hydroxybutyrate-co-4-hydroxybutyrate) with a 5% to 15% 4-hydroxybutyrate content blended with b) a poly(3-hydroxybutyrate-co-4- hydroxybutyrate) with a 20-50% 4-hydroxybutyrate content; a) poly(3-hydroxybutyrate- co-4-hydroxybutyrate) with a 5% to 15% 4-hydroxybutyrate content blended with b) a poly(3-hydroxybutyrate-co-5-hydroxyvalerate) with a 20% to 50% 5-hydroxyvalerate content; a) a poly(3-hydroxybutyrate-co-4-hydroxybutyrate) with 5% to 15% 4- hydroxybutyrate content blended with b) a poly(3-hydroxybutyrate-co-3- hydroxyhexanoate) having a 5%-50% 3-hydroxyhexanoate content; a) a poly(3- hydroxybutyrate-co-3-hydroxyvalerate) with a 5% to 22% 3 -hydroxy valerate content blended with b) poly(3-hydroxybutyrate-co-4-hydroxybutyrate) with a 20-50% 4- hydroxybutyrate content; a) a poly(3-hydroxybutyrate-co-3-hydroxyvalerate) with a 5% to 22% 3 -hydroxy valerate content blended with b) a poly(3-hydroxybutyrate-co-5- hydroxyvalerate) with a 20% to 50% 5-hydroxyvalerate content; a) a poly(3- hydroxybutyrate-co-3-hydroxyvalerate) with a 5% to 22% 3-hydroxyvalerate content blended with b) a poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) having a 5%-50% 3- hydroxyhexanoate content; a) a poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) with a 3% to 15%) 3-hydroxyhexanoate content blended with b) a poly(3-hydroxybutyrate-co-4- hydroxybutyrate) with a 20-50%) 4-hydroxybutyrate content; a) a poly(3-hydroxybutyrate- co-3-hydroxyhexanoate) with a 3% to 15% 3-hydroxyhexanoate content blended with b) a poly(3-hydroxybutyrate-co-5 -hydroxy valerate) with a 20% to 50%> 5-hydroxyvalerate; or a) a poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) with a 3%> to 15%> 3- hydroxyhexanoate content blended with b) a poly(3-hydroxybutyrate-co-3- hydroxyhexanoate) having a 5%-50% 3-hydroxyhexanoate content.

1099421.1

26. The composition of any claims 1-18, wherein the biobased polyhydroxyalkanoate is a) a poly(3 -hydroxybutyrate) homopolymer blended with b) a poly(3-hydroxybutyrate-co-4- hydroxybutyrate) with a 20-50% 4-hydroxybutyrate content and the weight of polymer a) is 5%> to 95%o of the combined weight of polymer a) and polymer b); a) a poly(3- hydroxybutyrate) homopolymer blended with b) a poly(3-hydroxybutyrate-co-3- hydroxyvalerate) with a 20%> to 50%> 5-hydroxyvalerate content and the weight of polymer a) is 5% to 95%. of the combined weight of polymer a) and polymer b); a) a poly(3 -hydroxybutyrate) homopolymer blended with b) a poly(3-hydroxybutyrate-co-3- hydroxyhexanoate) having a 5%>-50% 3-hydroxyhexanoate content and the weight of polymer a) is 5% to 95%> of the combined weight of polymer a) and polymer b); a) a poly(3-hydroxybutyrate-co-4-hydroxybutyrate) with a 5%> to 15% 4-hydroxybutyrate content blended with b) poly(3-hydroxybutyrate-co-4-hydroxybutyrate) with a 20-50%> 4- hydroxybutyrate content and the weight of polymer a) is 5% to 95%o of the combined weight of polymer a) and polymer b);a) a poly(3-hydroxybutyrate-co-4-hydroxybutyrate) with a 5%) to 15% 4-hydroxybutyrate content blended with b) poly(3-hydroxybutyrate-co- 5-hydroxyvalerate) with a 20% to 50%o 5-hydroxyvalerate and the weight of polymer a) is 5%o to 95%) of the combined weight of polymer a) and polymer b); a) a poly(3- hydroxybutyrate-co-4-hydroxybutyrate) with a 5% to 15% 4-hydroxybutyrate content blended with b) a poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) having a 5%>-50%> 3- hydroxyhexanoate content and the weight of polymer a) is 5% to 95%> of the combined weight of polymer a) and polymer b); a) a poly(3-hydroxybutyrate-co-3-hydroxyvalerate) with a 5%) to 22%o 3-hydroxyvalerate content blended with b) poly(3-hydroxybutyrate-co- 4-hydroxybutyrate) with a 20-50%> 4-hydroxybutyrate content and the weight of polymer a) is 5%o to 95% of the combined weight of polymer a) and polymer b); a) a poly(3- hydroxybutyrate-co-3-hydroxyvalerate) with a 5%o to 22% 3-hydroxyvalerate content blended with b) a poly(3-hydroxybutyrate-co-5-hydroxyvalerate) with a 20% to 50% 5- hydroxyvalerate and the weight of polymer a) is 5% to 95% of the combined weight of polymer a) and polymer b); a) a poly(3-hydroxybutyrate-co-3-hydroxyvalerate) with a 5% to 22%) 3-hydroxyvalerate content blended with b) a poly(3-hydroxybutyrate-co-3- hydroxyhexanoate) having a 5%>-50%> 3-hydroxyhexanoate content and the weight of polymer a) is 5% to 95%) of the combined weight of polymer a) and polymer b); a) a

1099421.1 poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) with a 3% to 15% 3-hydroxyhexanoate content blended with b) a poly(3-hydroxybutyrate-co-4-hydroxybutyrate) with a 20-50% 4-hydroxybutyrate content and the weight of polymer a) is 5% to 95% of the combined weight of polymer a) and polymer b); a) a oly(3-hydroxybutyrate-co-3- hydroxyhexanoate) with a 3% to 15% 3-hydroxyhexanoate content blended with b) a poly(3-hydroxybutyrate-co-5-hydroxyvalerate) with a 20% to 50%> 5-hydroxyvalerate and the weight of polymer a) is 5% to 95% of the combined weight of polymer a) and polymer b); or a) a poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) with a 3% to 15%> 3- hydroxyhexanoate content blended with b) a poly(3-hydroxybutyrate-co-3- hydroxyhexanoate) having a 5%-50% 3-hydroxyhexanoate content and the weight of polymer a) is 5% to 95%> of the combined weight of polymer a) and polymer b).

27. The composition of Claim 25 or 26, wherein the weight of polymer a) is 20 % to 60% of the combined weight of polymer a) and polymer b) and the weight of polymer b) is 40% to 80%) of the combined weight of polymer a) and polymer b).

28. The composition of any one of claims 21-27, wherein the polyhydroxyalkanoate is further blended with polymer c) a poly(3-hydroxybutyrate-co-4-hydroxybutyrate) with a 20% to 50%) 4-hydroxybutyrate content.

29. The composition of any one of claims 21-27, wherein the polyhydroxyalkanoate is further blended with c) a poly(3-hydroxybutyrate-co-5-hydroxyvalerate) with a 20% to 50% 5- hydroxyvalerate content.

30. The composition of any one of claims 21-27, wherein the polyhydroxyalkanoate further blended with c) a poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) with a 5% to 50% 3- hydroxyhexanoate content.

31. The composition of claim 28, 29 or 30, wherein the weight of polymer c) is 5% to 95%> of the combined polymer weight of polymer a), polymer b) and polymer c).

1099421.1

32. The composition of claim 31 wherein the weight of polymer c) is 5% to 40% of the combined polymer weight of polymer a), polymer b) and polymer c).

33. An article comprising the composition of any one of claims 1-32.

34. A method of preparing a based PHA composition, comprising

reacting an initial PHA having at least 10% recyclate PHA with a branching agent and a chain extender under conditions that cause melting, branching and chain extension of the PHA, wherein the resultant PHA composition has increased mechanical properties compared with the initial PHA, wherein the PHA is not polylactic acid.

35. A biobased composition prepared by the method of claim 34.

36. An article of claim 33, wherein the article is a film, sheet, laminate or thermoformed article.

37. A composition comprising a biobased polyhydroxyalkanoate polymer (PHA) and a chain extender wherein the PHA comprises at least 4% by weight of a 4HB component.

38. The composition of claim 37, wherein between about 10% and about 100 % by weight of the PHA is recyclate PHA.

39. The composition of claim 37, wherein between about 20% and 65% by weight of the PHA is recyclate PHA.

40. The composition of claim 37, wherein the chain extender is a carbodiimide.

41. The composition of claim 40, wherein the carbodiimide is a polymeric carbodiimide.

42. The composition of claim 40, wherein the carbodiimide is a monomeric carbodiimide.

43. The composition of claim 40, wherein the carbodiimide is a polymer 2,6- diisopropylphenyl type carbodiimide.

1099421.1 The composition of claim 40, wherein the weight percent of carbodiimide is between about 0.4 % and 1.2% of the total composition.

The composition of claim 44, wherein the weight percent of carbodiimide is about 1% of the total composition.

The composition of claim 37, wherein the composition further includes a branching agent.

The composition of claim 46, wherein the branching agent is selected from: dicumyl peroxide, t-amyl-2-ethylhexyl peroxycarbonate, l,l-bis(t-butylperoxy)-3,3,5- trimethylcyclohexane, 2,5-dimethyl-2,5-di(t-butylperoxy) hexane, 2,5-bis(t-butylperoxy)- 2,5-dimethylhexane, 2,5-dimethyl-di(t-butylperoxy)hexyne-3, di-t-butyl peroxide, benzoyl peroxide, di-t-amyl peroxide, t-butyl cumyl peroxide, n-butyl-4,4-bis(t- butylperoxy)valerate, 1 , 1 -di(t-butylperoxy)-3 ,3 , 5 -trimethyl-cyclohexane, 1 , 1 -di(t- butylperoxy)cyclohexane, 1 , 1 -di(t-amylperoxy)-cyclohexane, 2,2-di(t- butylperoxy)butane, ethyl-3 ,3 -di(t-butylperoxy)butyrate, 2,2-di(t-amylperoxy)propane, ethyl-3,3-di(t-amylperoxy)butyrate, t-butylperoxy-acetate, t-amylperoxyacetate, t- butylperoxybenzoate, t-amylperoxybenzoate, and di-t-butyldiperoxyphthalate.

The composition of any one of claims 37-47, wherein the concentration of branching agent is between 0.001 to 0.5% by weight of the PHA.

The composition of any one of claims 37-48, wherein the composition further comprises on or more additives.

The composition of any one of claims 37-49, wherein the composition further comprises a nucleating agent.

The composition of any one of claims 37-50, wherein the composition further comprises a flame retardant.

The composition of any one of claims 37-51 , wherein the composition further comprises a co-agent.

53. The composition of any one of claims 37-52, wherein the composition further comprises a UV absorber.

54. The composition of any one of claims 37-53, wherein the composition further comprises a cross-linking agent.

55. The composition of any one of claim 37-54, wherein the PHA comprises at least one copolymer having a 4HB component.

56. The composition of any one of claims 37-55, wherein the PHA is a blend of a poly 3HB and a poly(3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer with 8-14% 4HB by weight.

57. The composition of claim 56, further comprising a poly(3-hydroxybutyrate-co-4- hydroxybutyrate) copolymer with 25-33% 4HB by weight.

58. An article comprising the composition of any one of claims 37-57.

59. A masterbatch composition comprising the composition of claim 1 , wherein the

carbodiimide is 33% of the composition and the PHA is 67% of the composition.

60. The masterbatch of claim 59, wherein the PHA is a copolymer blend of 55-65% P3HB and 35-45% P3HB-4HB copolymer with 8-14% 4HB by weight and a blend of 15-25% P3HB, 75-85% P3HB-4HB copolymer with 8-14% 4HB by weight.

61. A method of preparing a PHA composition comprising at least 4% by weight a 4HB

component, comprising

combining an initial PHA comprising at least 4% by weight of a 4HB component with a chain extender under conditions that cause melting and chain extension of the

1099421.1 PHA, wherein the resultant PHA composition has increased mechanical properties compared with the initial PHA.

62. A composition prepared by the method of claim 61.

63. An article of claim 58, wherein the article is a film, laminate, sheet or thermo formed article.

64. The method of claim 61, further including incorporating a branching agent.

65. The composition of claim 4, wherein the weight percent of carbodiimide is between about 1.0 % and about 20 % of the total composition.

66. The composition of claim 65, wherein the weight percent of carbodiimide is about 10 % of the total composition.

67. The composition of claim 1 or claim 37, further comprising a non-PHA, thermoplastic polyester.

68. The composition of Claim 67, wherein the polyester is polybutylene adipate terephthalate or poly butylene succinate, poly butylene succinate adipate or combinations thereof.

1099421.1