MXPA03005806A - Water-responsive biodegradable polymer compositions and method of making same. - Google Patents

Abstract

The present invention is a hydrolytically modified, biodegradable polymer and a method of making a hydrolytically modifiable a biodegradable polymer. In a preferred embodiment, the invention is a method of grafting polar groups onto biodegradable polymers and modified biodegradable polymer compositions produced by the method. The polymer compositions are useful as components in flushable and degradable articles. Water-sensitive polymer blends and method of making those polymer blends are also disclosed.

Description

BIODEGRADABLE POLYMER COMPOSITIONS THAT RESPOND TO WATER AND METHOD TO MAKE THEMSELF Field of the Invention The present application relates to hydrolytically biodegradable and modified polymers and methods for making the hydrolytically modified biodegradable polymers. More particularly, the present invention relates to a biodegradable polymer selected from poly (hydroxyalkanoates), poly (alkylene-succinates) or polycaprolactone modified with a polar monomer and a process for modifying those polymers. In a preferred embodiment, the invention relates to a method for grafting two polar functional groups to a biodegradable polymer selected from poly (β-hydroxybutyrate-co-valerate), poly (butylene succinate) or polycaprolactone and grafted polymer compositions produced by the method.

Background of the Invention Even though the amount of plastics, hereinafter polymers, used in a variety of consumer products, packaging and medical articles has not been significantly increased over the past 20 years, the common perception is that more and more plastics are not degradable are filling and limiting the space of land fill. Despite this perceived disadvantage, polymers continue to be used in the manufacture of consumer goods, packaging and medical articles because plastics offer many advantages over more traditional materials; wood, glass, paper and metal. The advantages of using polymers include reduced manufacturing time and costs, mechanical and chemical properties, and decreased transportation and weight costs. It is the properties of improved chemical resistance of most plastics that result in their non-degradation.

The disposal of waste materials, including food waste packaging materials and medical waste, in typical landfills provides a relatively stable environment in which none of these materials is seen to decompose at an appreciable rate. Alternatively, the disposal options have been discussed incrementally and have been used to divert some waste fractions from their burial. Examples of these alternatives include municipal solid waste composting, anaerobic digestion, enzymatic digestion, and waste water drainage treatment.

Much controversy is associated with the disposal of medical waste. Both government agencies and members of the private sector have increasingly directed an in depth scrutiny and many funds towards this object. Admittedly, concerns about the fate of materials contaminated with infectious substances are valid and appropriate measures to establish the safety of workers in health care and the general public should be taken continuously.

Currently, medical waste can be cataloged as either reusable or disposable. The catalog of whether a certain waste can be reused or disposable is customarily determined according to the material from which the item was built and the purpose for which the item is used again.

After use, the medical items that are reused are cleaned and sterilized under astringent conditions to ensure disinfection. In comparison, disposable medical items are usually used only once. Even when the disposal procedures are not direct, they often involve several steps for safety against potential hazards. Typically, after use, disposable medical items must be disinfected or sterilized increasing a significant cost prior to disposal in a specially designated landfill or waste incinerator. As a result of this, the cost of disposing of contaminated single-use items is very high.Despite the high cost of the provision, single-use medical items are desirable because they ensure clean and non-contaminated equipment. Many times in the medical context the sterilization procedures carried out improperly can result in harmful effects, such as the transmission of infectious agents from one patient to another. Inappropriate sterilization can also be disastrous in a laboratory environment, where, for example, contaminated equipment can ruin experiments resulting in tremendous costs of time and money.

Currently, disposable medical fabrics are generally composed of thermoplastic fibers, such as polyethylene, polypropylene, polyesters, polyamides and acrylics. These fabrics may also include mixtures of heat set fibers such as polyamides, polyaryimides and cellulosics. These are typically 10-100 grams per square yard in weight and can be woven, knitted or otherwise formed by methods well known to those skilled in the textile arts while nonwovens can be thermally bonded, hydroentangled, placed in wet or perforated with needles and the films can be formed by extrusion blowing or setting or by setting of solution. Once these fabrics have been used they are difficult and expensive to dispose of and are not degradable.

The use of polymers for various disposable articles is widespread and well known in the art. In fact, the heaviest use of polymers in the form of films and fibers occurs in the packaging and disposables industries. Films used in the packaging industry include those used in merchandise bags, food and non-food packaging and garbage bags. In the disposable articles industry, general uses of polymers occur in the construction of diapers, personal hygiene items, surgical covers and hospital gowns, instrumental pads, bandages and protective covers for various items.

In view of the landfill space being depleted and the inadequate disposal sites, polymers are required to respond to water. Currently, even when polymers such as polyethylene, polypropylene, polyethylene terephthalate, nylon, polystyrene, polyvinyl chloride, and polyvinylidene chloride are popular for their superior extrusion and film and fiber-making properties, These polymers do not respond to water. In addition, these polymers are not generally compostable which is undesirable from an environmental perspective.

Polymers and polymer blends have been developed which are generally considered to respond to water. These are polymers which have been indicated to have adequate properties to allow them to break when exposed to the conditions that lead to composting. Examples of such polymers that respond to water are alleged to include those made of polyvinyl alcohol and biopolymers.

Even though materials made from these polymers have been used in articles containing fibers and films, many problems have been encountered with their use. Frequently the polymers and articles made from these polymers are not completely compostable or do not fully respond to water. In addition, some polymers that respond to water may be unduly sensitive to water, either by limiting the use of the polymer or by requiring some type of surface treatment for the polymer, often rendering the polymer unresponsive to water. Other polymers are undesirable because they have a heat resistance not suitable for wide spread use.

Personal care products such as diapers, sanitary napkins, adult incontinence garments and the like are generally constructed of a number of different components and different materials. Such items usually have some component, usually the backing layer, constructed of a water-repellent or liquid-repellent polymer material. The commonly used water barrier material includes polymer materials such as polyethylene film or copolymers of ethylene and other polar and non-polar raonomers. The purpose of the water barrier layer is to minimize or avoid the absorbed liquid which may, during use, exude the absorbent component and foul the wearer or the adjacent clothes. The water barrier layer also has the advantage of allowing a greater utilization of the absorbent capacity of the product.

Even though such products are relatively cheap, sanitary and easy to use, the disposal of a soiled product is not without these problems.

Typically, soiled products are discarded in a solid waste receptacle. This increases the accumulation of solid waste disposal and costs and presents health risks to people who come into contact with the soiled product. An ideal disposal alternative leads to a municipal drainage treatment and to private residential septic systems by disposing of the product soiled in a toilet with discharge of water. The products suitable for disposal in drainage systems are called "disposable". While it is convenient to discard water from such articles, prior art materials do not disintegrate in the water. This tends to clog the toilets and drainage pipes, often requiring a visit from the plumber. In a municipal drainage treatment plant, the liquid repellent material can interrupt operations by clogging the screens and causing disposal problems in the drainage. In such prior art products, it is therefore necessary, even when undesirable, to separate the barrier film material from the absorbent article before disposal with water discharge.

In addition to the article itself, typically the package in which the disposable article is distributed is also made of a water-resistant material, specifically water-resistant. Water resistance is necessary to avoid degradation of the package due to environmental conditions and to protect the disposable items there. Even when this container can be safely stored with other waste for commercial disposal, and especially in the case of individual packages or packages of the products, it would be more convenient to dispose of the package in the toilet with the disposable article discarded. However, where such a package is composed of a water resistant material, the aforementioned problems persist.

The use of lactic acid and lactide to make a stable polymer in water is well known in the medical industry. Such polymers have been used in the past to make stable sutures in water, staples, bone plates and biologically active controlled release devices. The processes developed for the manufacture of such polymers can be used in the medical industry and have incorporated techniques which respond to the need for high purity and biocompatibility in the final product. These processes, however, are typically designed to produce small volumes of high-value money products with less emphasis on cost and manufacturing performance.

It is generally known that lactide polymers or poly (lactides) are unstable. However, the consequence in stability has several aspects. One aspect is the biodegradation or other forms of degradation that occur when lactic polymers or articles manufactured from lactic polymers are discarded or composted after their useful life is completed. Another aspect of such instability is the degradation of the lactide polymers during processing at elevated temperatures such as, for example during the melting process by the final user buyers of the polymer resins.

In medical areas, there is a predominant need for polymers which are highly stable and therefore desirable for use in medical devices. Such demand has historically prevailed in the low-volume, high-value medical specialty market, but now it also prevails in the high-volume, low-value medical market.

As described in U.S. Patent No. 5,472,518, compositions composed of multilayer polymer films are known in the art. The utility of such structures lies in the manipulation of the physical properties in order to increase the stability or life time during the use of such a structure. For example, U.S. Patent No. 4,826,493 describes the use of a thin layer of hydroxybutyrate polymer as a component of a multilayer structure as a barrier film for diaper components and ostomy bags.

Another example of the use of multilayer films is found in U.S. Patent No. 4,620,999 which describes the use of a water soluble film coated with or laminated to a water insoluble film as a disposable bag. The patent discloses a package for waste of the body which is stable in human waste during use, but which can be made to degrade in the toilet, at a suitable rate to enter a blocked final drainage system, by adding a caustic substance to achieve a pH level of at least 12. Such structures usually consist of a layer of polyvinyl alcohol film coated with polyhydroxybutyrate.

A similar excretion treatment bag that allows disposal in a toilet or in a sediment container is described in Japanese Patent 61-42127. It is composed of an inner layer of a water resistant polymer, such as a polylactide, and an outer layer of a water dispersible polymer, such as polyvinyl alcohol. As described in this patent, there may be many examples of multi-layer films that are used in disposable objects. Most of these examples consist of films or fibers which are composed of internal layers of a polymer that can be degraded environmentally and of an outer layer of a polymer that responds to water. Typically, the inner layers are composed of polycaprolactone or ethylene vinyl acetate and the outer layer is composed of polyvinyl alcohol. These examples, however, are all limited to compositions consisting of multiple layers of different polymers and not encompassing current mixtures of different polymers.

A family of patents, European Patent 241178, Japanese Patent 61-223112 and United States of America Patent No. 4,933,182, describe a controlled release composition for treating periodontal disease. These controlled release compositions are composed of a therapeutically effective agent in a carrier consisting of particles of a limited water solubility polymer dispersed in a water soluble polymer. Although the carrier of these inventions includes the use of more than one polymer, the carrier described is not a mixture because the polymer of limited water solubility is incorporated in the water soluble polymer as particles varying in average particle size of from 1 to 500 microns.

The use of polymers for use in articles responsive to water is described in U.S. Patent Nos. 5,508,101; 5,567,510 and 5,472,518. This group of Patents describes a series of water-responsive compositions comprising a hydrolytically degradable polymer and a water-soluble polymer. The compositions of this group, however, consist of articles constructed of polymers which are first formed into fibers or films and are then combined. As such, the compositions are currently mini-layers of the individual polymer fibers or films. Therefore, even when the fibers and films of the polymers of such compositions are considered to be in very close proximity to one another, they are not as intimate as current polymer blends. The dispersion of one polymer within another in these compositions is not seen as approximately uniform since the individual polymers are essentially different and separate the fibers or films.

U.S. Patent No. 5,525,671 issued to Ebato et al. Describes a method for making a linear lactic copolymer of a lactide monomer and a monomer containing a hydroxyl group. The polymer described by Ebato is a linear lactic acid copolymer produced by reacting two monomers to form a linear polymer with a random block structure. Ebato does not describe inert copolymers.The polymer blend compositions for making fibers and films that are optimally combined are desirable because they are highly stable. The optimal combination of the polymers means that the polymers are connected as closely as possible without the requirements of copolymerization. Although the physically mixed individual polymer compositions are known, the polymer blends improved within the fibers and films, the individual fibers are microscopically and intimately interconnected and are desirable since the resulting composition is then more stable, flexible and versatile and in Most important way has improved properties and improved performance.

In addition to the need for polymer compositions that are highly stable, and therefore suitable for regular use in most disposable articles, there is a simultaneous need for such polymer compositions to respond to water. What is required, therefore, is a material that can be used for the manufacture of disposable articles and which responds to water. Such material must be versatile and inexpensive to produce. The material must be sufficiently stable for the intended use but is subject to degradation under predetermined conditions during disposal.

In addition, there is an increased emphasis on environmentally safe materials and coatings. These coatings reduce the use of solvent-based coatings and rely on an ever increasing degree on polar coatings, such as water-based material.

The utility of the graft copolymers of this invention includes, but is not limited to, materials that have a higher affinity to the polar coating.

Therefore, it is an object of this invention to provide a hydrolytically biodegradable and modified polymer.

Another object of this invention to provide a thermally processable polymer.

Another object of this invention to provide a commercially viable polymer.

A further object of this invention is to provide a thermally processable biodegradable polymer which is more compatible with polar polymers and other substrates or components.

Yet another object of this invention is to provide a hydrolytically biodegradable and modified polymer useful for making disposable biodegradable articles with water discharge.

Yet another object of this invention is to provide a hydrolytically biodegradable and modified polymer useful for making mixtures with improved mechanical and physical properties.

Another object of this invention is to provide a modified biodegradable polymer with improved melt processability.

A further object of this invention is to provide a polymer blend of a single microstructure.

Another object of this invention is to provide a modified biodegradable polymer which has improved compatibility in blends with polar polymers.

Another object of the invention is to provide improved polymer blends comprising ??? (β-hydroxybutyrate-co-valerate) poly (butylene succinate) and / or polycaprolactone.

Synthesis of the Invention This invention describes modified polymer compositions comprising a biodegradable polymer selected from poly (hydroxyalkanoate), poly (alkylene) succinates, or polycaprolactone grafted with a polar monomer, oligomer or polymer. This invention describes compositions of a polymer selected from poly (hydroxyalkanoate), such as poly (β-hydroxybutyrate), poly (-hydroxybutyrate-co- -hydroxivalerate); poly (alkylene succinates), such as poly (butylene succinate) and poly (ethylene succinate), or polycaprolactone grafted with 2-hydroxyethylmethacrylate or poly (ethylene glycol methacrylate) and a reactive extrusion process for making modified polymer compositions.

Poly (ß-hydroxybutyrate-co-valerate), poly (butylene succinate), poly (ethylene succinate) and polycaprolactone are biodegradable polymers which are commercially viable and generally thermally processable. For polar graft monomers in one or more of β (β-hydroxybutyrate-co-valerate), poly (butylene succinate) and polycaprolactone, the resulting modified polymer is more compatible with polar polymers and other polar substrates. For the development of a disposable material with water discharge, the modified polymer compositions of this invention have improved compatibility with water-soluble polymers, such as polyvinyl alcohol and polyethylene oxide than unmodified biodegradable polymers. The compatibility of the modified polymer compositions of the present invention with a polar material can be controlled by the monomer selection, the grafting level and the mixing process conditions. The confection of the compatibility of the mixtures with the modified polymer compositions leads to a better processing and improved physical properties of the resulting mixture.

The water-responsive compositions described in this invention have the unique advantage of being biodegradable so that compositions and articles made from the compositions can be degraded into aeration tanks by aerobic degradation and anaerobic digesters by anaerobic degradation in water treatment plants. waste of water. Therefore, articles made from the compositions of this invention will not significantly increase the volume of accumulated sediments in the waste water treatment plants.

In another embodiment of the present invention, there is provided a homogeneous water-sensitive polymer mixture comprising a biodegradable polymer grafted with a polar monomer, oligomer or polymer or a combination thereof and a water soluble polymer.

In another embodiment of the present invention, there is provided a novel polymer composition comprising a mixture of a first biodegradable polymer grafted with a polar monomer, oligomer, or polymer or a combination thereof and a second biodegradable polymer grafted with a polar monomer , oligomer or polymer or a combination thereof, wherein said first and second biodegradable polymers are different polymers.

Brief Description of the Figures Figure 1 is a graph of the time against torsional force during the reactive extrusion of an embodiment of the present invention.

Figure 2 is a comparative proton R spectrum for poly (E-hydroxybutyrate-co-E-hydroxyvalerate) and for poly (phé-hydroxybutyrate-co- -hydroxivalerate) grafted with 2-hydroxyethylmethacrylate.

Figure 3 is a graph of apparent melt viscosities at various apparent cut rates and rheology curves for unmodified poly (-hydroxybutyrate-co- -hydroxivalelate) and poly (β-hydroxybutyrate-co-β-hydroxyvalerate) grafted with 2-hydroxyethyl methacrylate of example 1.

Figure 4 is a graph of the curves of the DSC curves for poly (β-hydroxybutyrate-co-phé-hydroxyvalerate) and for poly (hydroxybutyrate-co-phé-hydroxyvalerate) grafted with 2-hydroxyethyl methacrylate.

Figure 5 is a plot of the torsional force against time during a reactive extrusion of two samples of poly (butylene succinate) grafted with poly (ethylene glycol) methacrylate of Example 2.

Figure 6 is a comparative proton MR spectrum for grafted and unmodified poly (butylene succinate) of the reactive extrusion on a Haake extruder of Example 2.

Figure 7 is a graph of the melt rheology curves for the unmodified poly (polybutylene succinate) and poly (butylene) succinate grafted with poly (ethylene glycol) methacrylate over a Haake exoser of example 2.

Figure 8 is a graph of melt rheology curves for poly (butylene succinate) and poly (butylene succinate) grafted with 2-hydroxyethyl methacrylate on the ZSK-30 extruder of example 2.

Figure 9 is a graph of DSC curves for unmodified poly (butylene succinate) and poly (butylene succinate) grafted with poly (ethylene glycol) methacrylate from Example 2.

Figure 10 is a graph of DSC curves for ungrafted poly (butylene succinate) and poly (butylene succinate) grafted with 2-hydroxyethyl methacrylate from Example 2.

Figure 11 is an SEM image (electron microscopy scan) of the topological morphology of the fracture surface of a film made of a 60/40 mixture of poly (butylene succinate) / polyoxyethylene showing a two-phase structure.

Figure 12 is an electron microscopy scanning image of a topological morphology of the fracture surface of a film made of a 60/40 mixture of injected poly (butylene) succinate / grafted polyoxyethylene showing a two-phase microstructure and an improved compatibility.

Figure 13 is a scanning electron microscopy image using BEI (spreading-posterior electronic imaging) of the topological morphology of the fracture surface of a film made from a 60/40 mixture of polyoxyethylene poly (butylene succinate) showing a 2 phase microstructure.

Fig. 14 is a scanning electron microscopy image employing a spherical-posterior electronic imaging of the topological morphology of the fracture surface of a film made from a 60/40 mixture of polybutylene succinate injected / grafted polyoxyethylene where a polyoxyethylene phase is not visible.

Figure 15 is a graph of a DSC analysis of poly (butylene succinate / polyoxyethylene) blends showing the observed decrease in Tm for the polyoxyethylene phase of the reactive mixtures of poly (butylene succinate) / polyoxyethylene to be increased by percent polyoxyethylene in the mixtures.

Figure 16 is a graph of a DSC analysis of poly (butylene succinate / polyoxyethylene) mixtures showing an increase in the change in Tm (A ^ J for the polyoxyethylene phase of the reactive mixtures compared to the physical mixtures when being increased the percent of polyoxyethylene in the mixtures.

Figure 17 is a DSC analysis graph of polyoxyethylene (butylene polysuccinate) mixtures showing a comparison between the DSC curves for reactive and physical 30/70 mixtures of poly (butylene succinate) / polyoxyethylene.

Figure 18 is a graph of the melt rheology curves of reactive and physical blends of 20/80 and 60/40 poly (butylene succinate) / polyoxyethylene, as well as the melting rheology curve for poly alone (butylene succinate).

Detailed description of the invention The present invention comprises a biodegradable polymer which is modified by the graft polymerization with the monomer, oligomer or polar polymer. The present invention also comprises a polymer composition which includes a mixture of a biodegradable polymer which is modified by graft polymerization with a polar monomer, oligomer or polymer and with either a water sensitive polymer or another biodegradable polymer which is modified by graft polymerization with a monomer, oligomer or polar polymer. This polymer composition can be made into films, fibers, coatings, beads, powders and the like and can be used to make fabrics, garments and articles such as covers, towels, drapes, overwraps, suits, head coverings, face masks. , shoe covers, CSR wraps, sponges, bandages, ribbons, inner pads, linings, wash cloths, sheets, pillow covers, napkins, cloth type outer covers, surgical products and wound care products. The present invention is also particularly suitable for use for biodegradable personal care products, such as diapers, training pants, tampons for women, pant pads and liners and spacer films therefor, adult incontinence products, wet cleaning cloths and / or cleaners and any woven, nonwoven or otherwise formed materials. Such products can be used in the medical industry, both in hospitals and facilities for external patients and domestic environments.

Biodegradable polymers that are useful in the present invention include poly (β-hydroxyalkanoates) ("PHA"), such as poly (β-hydroxybutyrate) ("PHB"), poly (β-hydroxybutyrate ~ co-S-hydroxyvalerate) ( "PHBV"); poly (alkylene succinates) ("PAS"), such as poly (ethylene succinate) ("PES") and poly (butylene succinate) ("PBS"); and polycaprolactones ("PCL") that are hydrolytically degradable. For certain embodiments of the present invention, polylactides ("PLA") are useful as a biodegradable polymer.

The poly (-hydroxybutyrate-co-E-hydroxyvalerate) reams can be made by either the carbohydrate fermentation process and an organic acid by a microorganism; for example Alcáligenes eutrophus or through the use of transgenic plants ("Plastics Biodegradable Plants", CHE TECH, September 1996, pages 38-44). Poly (-hydroxybutyrate-co-S-hydroxyvalerate) is a biodegradable polymer and has the chemical structure.

The molecular weight of the poly (β-hydroxybutyrate-co-β-hydroxyvalerate) useful in the present invention is not critical to the present invention and can generally be about 20,000 to 2,000,000 grams per mole. The poly (phé-hydroxybutyrate-co-β-hydroxyvalerate) compositions described in the following examples were made by using a class of poly (β-hydroxybutyrate-co-S-hydroxyvalerate) purchased from Zeneca Bio-Products of Ilmington, Delaware, under the designation Biopol® D600G The poly (fe-hydroxybutyrate-co-S-hydroxyvalerate) purchased from Zeneca Bio-Products is biodegradable Any poly (-hydroxybutyrate-co-E-hydroxyvalerate) can be selected for use in this invention, and the molecular weights of the poly (β-hydroxybutyrate-co-β-hydroxyvalerate) can vary depending on the desired properties and use.

Polyalkylene succinate resins ("PAS") are produced by different synthetic methods, such as the reaction product between aliphatic dicarboxylic acids and ethylene glycol or butylene glycol. Poly (butylene succinate) ("PBS") is commercially available from Showa Highpolymer Company of Tokyo, Japan under the trademark Bionolle®. Poly (butylene succinate) is a biodegradable polymer and has the following chemical structure: The molecular weight of the poly (alkylene succinate) useful in the present invention is not critical to the present invention and can generally be about 20,000 to 2,000,000 grams per mole. The poly (butylene succinate) compositions described in the following examples were made by the use of poly (butylene succinate) class 1020 or 1040 Bionolle® purchased from Showa Highpolymer Company. Any poly (alkylene succinate) can be selected for use in this invention, and the molecular weights of poly (alkylene succinate) can vary depending on the desired properties and use.

Polycaprolactone ("PCL") resins are produced by different synthetic methods, such as ring-opening polymerization of g-caprolactone. A commercial example of polycaprolactone is sold under the Tone® brand available from Union Carbide of Danbury, Connecticut and is a biodegradable polymer with the following chemical structure.

The molecular weight of the polycaprolactones useful in the present invention is not critical to said invention and can generally be about 50,000 to 1,000,000 grams per mole. The polycaprolactone compositions described in the following examples were made by using polycaprolactones P-767 and P-787 purchased from Union Carbide Corporation of Danbury Connecticut (the Tone® polymers catalog number UC-261). The purchased polycaprolactones from Union Carbide Corporation are biodegradable and have a melt flow of 1.9 ± 0.3 g / minute for P-767 (80 ° C 44 pounds per square inch, ASTM 1238-73) and 1.0 + 0.2 g / min. (125 ° C, 44 pounds per square inch). Any polycaprolactone may be selected for use in this invention, and the molecular weights of the polycaprolactones may vary depending on the desired properties and use.

The monomers, oligomers or polar polymers useful in the present invention include ethylenically unsaturated monomers containing a polar functional group such as hydroxyl, carboxyl, halo-, glycyl, cyano, amino, carbonyl, thiol, sulphonic, sulfonate, and the like are suitable for this invention. Examples of the polar vinyl monomers useful in the present invention include, but are not limited to poly (ethylene glycol) acrylate, poly (ethylene glycol) alkyl ether acrylate, poly (ethylene glycol) methacrylate, poly (ethylene glycol) alkyl ether methacrylate, acrylic acid, maleic anhydride, itaconic acid, sodium acrylate, 3-hydroxypropyl methacrylate, 2-hydroxyethyl methacrylate, 3-hydroxypropyl acrylate, 2-hydroxyethyl acrylate, acrylamide, 2-bromoethyl methacrylate, 2-chloroethyl methacrylate, 2-iodoethyl methacrylate, 2-bromo ethyl acrylate, 2-chloroethyl acrylate, 2-iodoethyl acrylate, glycyl methacrylate, 2-cyanoethyl acrylate, glycyl acrylate, 4-nitrophenyl acrylate, pentabromophenyl acrylate, poly (propylene glycol) methacrylates, poly (propylene glycol) acrylates, 2-propene-1-sulfonic acid and its sodium salt, 2- sulfoethyl acrylate, 2-sulfoethyl methacrylate, 3-sulfopropyl acrylate, 3-sulfopropyl methacrylate or mixtures thereof. Preferred ethylenically unsaturated monomers contain a group of polar function and include 2-hydroxyethyl methacrylate (HEMA) and poly (ethylene glycol) methacrylate (PEG-MA). It is expected that a wide range of polar vinyl monomers will be able to impart polar functionality to the biodegradable polymers and be effective monomers for grafting.

The grafted biodegradable polymers may contain about 1 to 20% by weight of grafted polar monomers, oligomers or polymers. Preferably the grafted biodegradable polymer contains about 2.5 to 20% by weight of grafted polar monomers, oligomers or polymers and more preferably about 2.5 to 10% by weight of grafted polar monomers, oligomers or polymers.

Both 2-hydroxyethyl methacrylate (catalog number Aldrich 12,863-8) and poly (ethylene glycol) methacrylate (catalog number Aldrich 40,954-5) used in the examples were supplied by Aldrich Chemical Company. The poly (ethylene glycol) methacrylate purchased from Aldrich Chemical Company was a poly (ethylene glycol) ethyl ether methacrylate having a number average molecular weight of about 246 grams per mole. The analogs of 2-hydroxyethyl methacrylate and of poly (ethylene glycol) methacrylate are useful in the present invention. The 2-hydroxyethyl methacrylate analogs include for example 3-hydroxypropyl methacrylate and 4-hydroxybutyl methacrylate; the poly (ethylene glycol) methacrylate analogs have molecular weights ranging from about 200 grams / mol to about 10,000 grams per mol.

The method for making grafted biodegradable polymer compositions has been demonstrated by the reactive extrusion process. The grafting reaction can be carried out in other reaction devices as long as the necessary mixing of the biodegradable polymer of the polar monomer and any other reactive ingredients is achieved and sufficient energy is provided to effect the grafting reactions; for example, by creating free radicals to initiate the graft reaction process. The reactions are desirably carried out in a melted polymer phase; for example, in the absence of a bulk solvent. This is a highly effective process since the step of removing the solvent is not necessary in the process.

Other reactive ingredients which can be added to the compositions of this invention include initiators such as Lupersol® 101, a liquid organic peroxide available from Elf Atochem North America Inc., of Philadelphia Pennsylvania. Free radical initiators useful in the practice of this invention include acyl peroxides such as benzoyl peroxide; dialkyl, diaryl or aralkyl peroxides, such as butyl di-t-peroxide; dicumyl peroxide; cumyl butyl peroxide; 1,1-di-t-butyl peroxide-3,5-trimethylcyclohexane; 2,5-dimethyl-2,5-di (t-butyl peroxy) hexane; 2,5-dimethyl-2,5-bis (t-butyl peroxy) hexine-3 and bis (a-t-butylperoxy isopropyl benzene); peroxy esters such as t-butyl peroxypiplalate; t-butyl perophthoate; t-butyl perbenzoate; 2,5-dimethyl-exyl-2,5-di (perbenzoate) t-butyl di (terephthalate); dialkyl peroxycarbonates and peroxydicarbonates; hydroperoxides such as t-butyl hydroperoxide, p-methane hydroperoxide, pinano hydroperoxide and eumeno hydroperoxide and ketone peroxides, such as cyclohexanone peroxide and methyl ethyl ketone peroxide. Azo compounds, such as azobisisobutyronitrile can also be used.

The amount of free radical initiator and total blend compositions which include either biodegradable polymers and / or water soluble polymers and a polar monomer or polar vinyl monomer blend vary from about 0.1 to about 1.5% by weight. At a very low amount of free radical initiator, there is not a sufficient initiator present to initiate a grafting reaction. If the amount of free radical initiator is very high, it will create an undesirable crosslinking of the polymer composition. Crosslinked polymers are undesirable in the present invention because they can not be processed into films, fibers or other useful products.

In addition, other components known in the art can be added to the graft polymers of this invention to further improve the properties of the final material. For example, polyethylene glycol can also be added to improve the melt flow by reducing the melt viscosity. Additives or other types can also be incorporated to provide specific properties as desired. For example, antistatic agents, pigments, dyes and the like can be incorporated into the polymer compositions. Additionally, the processing characteristics can be improved by incorporating lubricants or slip agents into the blends made of the polymers of the invention. All these additives are generally described here. However, it has unexpectedly been discovered as part of the present invention that a mixture of polylactides and poly (β-hydroxybutyrate-co---hydroxyvalerate) makes a cold poly (β-hydroxybutyrate-co---hydroxyvalerate) at an acceptable rate and also makes the polylactide more flexible so that these materials can be used in the products described here; while any biodegradable polymer alone was unsuitable for such applications.

In another embodiment of the present invention, the mixtures of the modified biodegradable polymer of the present invention and the water soluble polymers were made. Such mixtures demonstrated an increased water sensitivity of the composition which promoted the rate of hydrolytic degradation of the biodegradable polymers by increasing the exposed surface area of the biodegradable polymer followed by the dissolution of the water soluble component. The water-soluble polymers with which the modified biological polymers of the present invention can be blended include polyethylene oxide, polyvinyl alcohol, hydroxypropyl cellulose, polyacrylamide, sulfonated polyesters and polyacrylic acid. The weight fraction of the modified biodegradable polymer in the mixture ranges from 1% to 99% by weight. This fraction determines the water response of the mixtures. A wide range of water responses includes dispersibility in water, disintegration in water, weakening in water and stability in water, as these terms are defined hereafter.

The presence of biodegradable polymers or modified biodegradable polymers in the blends used to make the fibers, films or other forms reduces the sensitivity of pure water-soluble polymers, such as polyvinyl alcohol ("PVOH") in use. Biodegradable polymers grafted with the polar monomer or a monomer mixture is preferred for improved compatibility with the highly polar water soluble polymers, such as polyvinyl alcohol, in order to obtain superior mechanical and physical processing properties. It is possible to use the blends to make other forms than fibers or films and to thermally form the blends in complex forms.

As used herein, the term "water dispersible" means that the composition dissolves or breaks into smaller pieces than the openings of a 20 mesh grid after being immersed in water for about 5 minutes. The term "water-disintegrable" means that the composition breaks into multiple pieces within 5 minutes of submerging in water and that some of the pieces will be trapped by a 20-mesh grid without slipping through it in the same manner as a thread through the eye of a needle. The term ebilitable in water "means that the composition remains in one piece but weakens and loses rigidity after 5 minutes of submerging in water and becomes drapeable, for example, it is bent without an external force being applied to it when it is it remains on one side in a horizontal position The term "stable in water" means that the composition does not become bent after 5 minutes of submerging in the water and remains in one piece after the water response test.

As used herein, the term "graft copolymer" means a copolymer produced by the combination of two or more chains of constitutionally or configurationally different characteristics, one of which serves as a column backbone, and at least one of the which is joined at some points along the column and constitutes a side chain. The molar amount of the grafted monomer, the oligomer or the polymer; for example, the side-chain species may vary but must be greater than the molar amount of the parent species. The term "grafted" means a copolymer that has been created which comprises chains or side species attached at some point along the column of the parent polymer. The term "blend" as applied to polymers means an intimate combination of two or more polymer chains of constitutionally or configurationally different characteristics which are not linked to each other. Such mixtures may be homogeneous or heterogeneous. (See the work of Sperling L.H., Introduction to the Science of Physical Polymer 1986 pp. 44-47 which is hereby incorporated by reference in its entirety).

Preferably, the mixture is created by combining two or more polymers at a temperature above the melting point of each polymer.

There are several methods for making the modified biodegradable polymers of the present invention. One method is a solution-based grafting method in which the biodegradable polymer is dissolved in a solvent, which are added desired amounts of the free radical initiator and a polar monomer or a mixture of two or more polar monomers, particularly those polar vinyl monomers. After sufficient grafting is complete, the solution is purified to remove the solvent and unreacted monomer, resulting in a grafted biodegradable polymer. This method is a relatively labor intensive and cost-intensive method compared to the melt grafting methods described below.

The other method is based on a melt phase reaction in which a melted biodegradable polymer is reacted with a free radical initiator and a polar monomer or a mixture of two or more polar monomers, particularly the polar vinyl monomers. The modification of the melting phase is called "reactive extrusion" in the sense that a new species of polymer is created with the modification reaction. There are several specific methods for carrying out the graft modification reaction in a melt. First, all the ingredients, including a biodegradable polymer, a free radical initiator, a polar monomer or a mixture of polar monomers in a predetermined ratio are added simultaneously to a melt mixing device or to an extruder. Second, the biodegradable polymer can be fed to a feed section of a twin screw extruder and subsequently melted, and a mixture of a free radical initiator and a monomer or polar mixture of polar monomers is injected into the melted of biodegradable polymer under pressure, then allowing the resulting melted mixture to react. Third, the biodegradable polymer is fed to the supply section of a twin screw extruder, and then the free radical initiator and the polar monomer, or a mixture of monomers, are supplied separately to the twin screw extruder at different points along the length of the extruder. Extrusion from the heated extruder is carried out under high shear and intensive dispersion and distribution mixing conditions resulting in a biodegradable graft polymer of high uniformity.

Water-soluble and hydrolytically degradable polymer mixture compositions according to the present invention are produced by a melt mixing process. It is desired according to the present invention to mix or combine two of the components in an extruder, such as a twin screw or single screw extruder under appropriate temperature and cut / pressure conditions to ensure mixing. The blending process can also be carried out in a load mixing device such as a melt mixer or a kneader. The modified biodegradable polymer or water soluble polymer, such as polyvinyl alcohol ("PVOH") / may be fed into the extruder / mixer either simultaneously or in sequence.

The present invention discloses homogeneous polymer mixture compositions that selectively respond to water comprising modified biodegradable polymers and mixtures of water soluble polymers; for example modified biodegradable polymers such as poly (β-hydroxybutyrate, poly (β-hydroxyalkanoate), α (β-hydroxybutyrate-co-S-hydroxyvalerate), poly (alkylene succinates), PES, poly (butylene succinate) , or polycaprolactone graft polymerized with 2-hydroxyethyl methacrylate or poly (ethylene glycol) methacrylate, mixed with one or more water-soluble polymers, such as polyvinyl alcohol.The term "homogeneous polymer blend composition" as used herein, means that the polymer mixture forms a continuous and cohesive structure of a modified biodegradable polymer and a water soluble polymer; for example a polyvinyl alcohol, which is macroscopically homogeneous. Microscopically, the size of the dispersed phase is on the order of several microns or less. A homogeneous polymer mixture composition can be achieved by mixing the modified biodegradable polymer and the water soluble polymer; for example polyvinyl alcohol, at a temperature above the melting point of the polymer having the highest melting point, and below the decomposition point of the polymer having the lowest decomposition point, in order to form a homogeneous melted mixture of the polymers (before cooling to a solid form, for example films or fibers). For the homogeneous polyvinyl alcohol and polylactide polymer blend compositions, the polymer having the higher melting point is a polyvinyl alcohol and the polymer having the lowest decomposition point is also polyvinyl alcohol. The melting point for the polyvinyl alcohol is generally about 180-190 ° C, and more specifically about 183 ° C. The decomposition point of the polyvinyl alcohol is approximately 210 ° C. The resulting composition looks like islands of poly (-hydroxybutyrate-co-β-hydroxyvalerate) grafted with 2-hydroxyethyl methacrylate in a sea of polyvinyl alcohol, for example, and at a microscopic level that has the appearance of an approximately uniform distribution of poly ( S-hydroxybutyrate-co- -hydroxivalerate) grafted with 2-hydroxyethyl methacrylate between polyvinyl alcohol. The homogeneous polymer blend composition of the present invention therefore has a very fine dispersion of the modified biodegradable graft polymer islands of average size of less than about 0.3-0.4 microns dispersed within a water soluble polymer.

Based on the uniformity of the dispersion, the "polymer mixture" of the present invention can be distinguished from "mixed polymers". The compositions of the present invention may comprise polymers that are mixed above the melting point of the polymer having the highest melting point (eg> 183 ° C for polyvinyl alcohol), and below the decomposition points of the polymer having the lowest decomposition point (210 ° C for polyvinyl alcohol) and under a high cut; for example, at a cut-off rate of 100 s-1 or higher. The homogeneous polymer blend composition is therefore formed before the polymers are formed into films to fibers, resulting in polymer compositions which are highly and intimately interconnected having a selectively uniform dispersion. Such compositions can be distinguished from those comprising mixed polymers consisting of polymers which are mixed after they have been formed into fibers or films, resulting in compositions which do not have an approximately uniform dispersion and often appear as individual polymers in layers or mixed together. In summary, when the individual polymers are mixed at temperatures above the melting point of the polymer having the highest melting point, and below the decomposition point of the polymer having the lowest decomposition point and a high mechanical cut, a distribution results. and approximately uniform dispersion of the polymers. In contrast, when the individual polymers are blended according to standard practices, a mixed polymer composition results where the polymers are not integrally associated.

The water sensitivity of the polymer compositions can be controlled according to the degree of homogeneity of the polymer blends. The mixing, cutting, extrusion and other mixing techniques, as well as the relative proportions of the polymer resins used, can be manipulated to determine the microstructure of the polymer compositions. The "microstructure" of the polymer blends specifically refers to the size and distribution of the modified biodegradable polymer islands of graft within the sea of water soluble polymer, for example. The size of the islands can vary from approximately 0.1 to 5.0μ ??. Generally, by increasing the size of the islands, and / or the distance between them decreases, the composition gains greater mechanical resistance in wet and loses flexibility in the water. For example, for water dispersible compositions, the islands are typically small (approximately 0.2 ~ 1.0pm) and are distributed so that they are separated from each other. For water-disintegrable compositions, the islands are closer together with a few islands that may still be connected to one another. For compositions that can weaken in water, the islands may be in very close proximity and a majority of these appear as large lumps.

The method for making films of the present invention affects the morphology of the film. To form a film of a modified biodegradable graft polymer finely dispersed from particles that are spherical, nearly spherical or ellipsoidal, it is desirable to use a non-orientation method to form the film. One method of non-orientation for making films is thermomechanical pressing. An example of thermomechanical pressing is described in the example given below. Orientation methods for making the films, such as extruding or blowing films, results in films in which the dispersed phase has a morphology containing a modified biodegradable graft polymer in a fibrous structure through the continuous phase of soluble polymer in Water. The oriented films have a reduced response to water and are not dispersible in cold water but are only weakened in cold water or disintegrable in cold water. The present invention provides improved compositions and methods for making compositions with improved morphologies and responses to cold water.

An embodiment of the present invention is a homogeneous polymer blend composition comprising from about 1 to about 35% by weight of graft modified biodegradable polymer and from about 65 to about 99% by weight of soluble polymer in water, wherein said composition is dispersible in water. The composition is characterized by a morphology of modified biodegradable graft polymer particles dispersed in a continuous phase of water soluble polymer. The term "water dispersible" is used herein, meaning that the composition will dissolve or break into pieces smaller than a 20 mesh after having been tested with water at room temperature (18-22 ° C) for two minutes. The "water test" as used herein, means preparing a sample of the composition and then immersing it in a container filled with water for 5 minutes, followed by stirring the container for approximately 30 seconds in a mechanical stirring device and then empty the contents of the container through a grid of 20 standard meshes.

Another embodiment of the present invention is a homogeneous polymer blend composition comprising from about 35 to about 45% by weight of graft modified biodegradable polymer and from about 65 to about 55% by weight of soluble polymer in water where such composition is disintegrable in water. This composition is also characterized by a morphology of fine biodegradable modified graft polymer particles dispersed in a continuous phase of water soluble polymer. The size of the modified biodegradable polymer domains is greater than those domains for the water dispersible compositions. The term "water-disintegrable" as used herein, means that the composition will break into multiple pieces after 2 minutes and some of the pieces of the composition will be trapped by a 20-mesh grid.

Another embodiment of the present invention is a composition comprising from about 45 to about 55 percent modified biodegradable graft polymer and from about 55 to about 45% by weight water soluble polymer, wherein composition can weaken in water. The composition is characterized by a morphology of the fine biodegradable modified graft polymer particles dispersed in a continuous phase of water soluble polymer. The domain size of the modified biodegradable polymer is slightly larger than for water-disintegrable compositions. The term "weak in water" as used herein, means that the composition remains in one piece but weakens and loses its stiffness after 5 minutes and can become bent; for example; for example, it is bent without an external force being applied to the composition when this is held by a corner in a horizontal position. The term "stable in water" as used herein means that the composition does not bend and remains in one piece after being tested with water.

To make a composition that is selectively water dispersible, about 1-35% of the modified biodegradable graft polymer and about 65-99% of the water soluble polymer are combined. To make a composition that is water-selectively disintegrable, about 35-45% of the modified biodegradable graft polymer and about 65-55% of the water-soluble polymer are combined. To make a composition that is selectively water weakable, about 45-55% of biodegradable modified graft polymer and about 55-45% of water soluble polymer are combined. To make a composition that is selectively stable in water, about 55-99% of modified biodegradable graft polymer and about 45-1% of water soluble polymer are combined.

Another embodiment of the present invention that is described is a reactive polymer mixture composition of a grafted water-soluble polymer, such as grafted polyethylene oxide or grafted polyvinyl alcohol and a grafted biodegradable polymer, such as poly (β-hydroxybutyrate). grafted co-f-hydroxyvalerate), grafted poly (alkylene succinate), and grafted polycaprolactones. The ratio of water-soluble polymer grafted to biodegradable polymer grafted to the mixture of the present invention is between 1:99 and 99: 1 by weight. Examples of the graft monomers, the amounts of graft monomer in relation to the total weight of the biodegradable polymers and the water-soluble polymer, the free radical initiators for the grafting reaction and the amount of free radical for the reaction of grafts are the same as described above for the grafted polymers.

The processing characteristics of the polymer blends for the films can be improved by the optional incorporation of lubricants or slipping agents into the blends. Such lubricants are well known in the art and include TWEEN 20® TURGITOL® NP 13 available from Union Carbide Corporation (of Danbury Connecticut) and various fatty acids and fatty acid derivatives such as ENAMIDA® available from itco Chemical (USA). In addition, the mixtures may contain other components to improve the properties of the resulting material. For example, polyethylene glycol can be added to lower the melt viscosity of the melted mixture to a suitable range for other processes such as the meltblowing process or the non-woven process with spraying. Suitable polyethylene glycols are available from Union Carbide under the trade name CARBOWAX®.

The polymer blending is an important aspect of the manufacture of the compositions of the present invention.

Depending on the parameters such as the selection of mixing techniques, temperature profiles and pressure applications, the final water response amounts of the compositions may be affected.

The present invention is illustrated in more detail by the following specific examples. It should be understood that these examples are illustrative embodiments and that this invention is not limited by any of the examples or details in the description. Rather, the claims appended here should be broadly considered within the scope and spirit of the invention.

Example 1 Reactive Extrusion of Poly (hydroxybutyrate-co-S-hydroxyvalerate with 2-hydroxyethyl methacrylate and poly (ethylene glycol) methacrylate) The chemistry of reactive extrusion for the graft of poly (S-hydroxybutyrate-co-B-hydroxyvalerate) is shown below: Reactive Extrusion chemistry for grafting poly (S-hydroxybutyrate-co-valerate) V peroxide, cut, t Where X = -C00CH2CH20H (HEMA) and -C00- (CH2CH20) n-C2H5 (PEG-MA), gives a mixture of: 1???? ÍIEMA O- CCH2C-j- j- 0- CCH2C- † Reactive Extrusion Process A twin counter-rotating screw extruder made by Haake of Paramus, New Jersey was used to prepare poly (B-hydroxybutyrate-co-hydroxyvalerate). The extruder had 2 conical screws of 30 mm in the supply port and 20 mm in the matrix. The length of the screw was 300 millimeters. The poly (β-hydroxybutyrate-co-E-hydroxyvalerate resin (Biopol® P600G from Zeneca Bio-Products) was fed to the delivery port, the 2-hydroxyethyl methacrylate monomer and the Lupersol® 101 were both fed to the supply port by the Eldex pumps The matrix used to extrude the modified poly (ß-hydroxybutyrate-co-Shydroxivalelate) yarns had two openings of 3 millimeters in diameter which were separated by 5 millimeters.The threads of poly (ß-hydroxybutyrate-co -Bydroxivalerato) were cooled with a water bath, unlike polylactide ("PLA"), the poly (B-hydroxybutyrate-co-Ehydroxivalerate) exhibited an extremely low solidification after initial cooling in water. In fact, the polymer threads could not be sufficiently cooled in the ice water (~ 0 ° C) quickly enough to make pellets. Interestingly, the grafted poly (β-hydroxybutyrate-co-hydroxyvalerate) exhibited elastomeric properties in the melt. The threads can be easily stretched and will retract to their initial length. This material property was not observed for grafted polylactide or grafted polyolefins. After solidification, the threads of grafted poly (β-hydroxybutyrate-co-Shydroxivalelate) were extremely rigid and brittle. The solidification of both the unmodified poly (6-hydroxybutyrate-co-Shidroxivalerato) and the grafted poly (-hydroxybutyrate-co-hydroxyvalerate) took several minutes to complete, so that the polymer samples were collected in small pieces, were left solidify overnight and were then cut into small pieces.

The poly (-hydroxybutyrate-co-β-hydroxyvalerate) was fed into the extruder with a volumetric feeder at a rate of 5.0 1 pound / hour. The 2-hydroxyethyl methacrylate and peroxide were grafted to the extruder at yields of 0.25 pounds per hour and 0.020 pounds per hour, respectively. In one embodiment, the screw speed was 150 revolutions per minute.

The two samples of poly (S-hydroxybutyrate-co-β-hydroxyvalerate) were produced on a Haake extruder. Table 1 given below shows the process conditions for the reactive extrusion of the poly (β-hydroxybutyrate-co- -hydroxivalerate) with 2-hydroxyethyl methacrylate on the Haake extruder.

Table 1-Process Conditions for Preparing Poly (ß-hydroxybutyrate-co-B-hydroxyvalerate) grafted with 2-hydroxyethylmethacrylate The torsional force on a Haake extruder was monitored during each reactive extrusion. Figure 1 shows a diagram of the torsional force against time during reactive extrusion. At the beginning of the reaction, when the 2-hydroxyethyl methacrylate and the peroxide were added, the torsional force was observed to be significantly decreased. When the torsional strength was stabilized, the sample of poly (-hydroxybutyrate-co-phé-hydroxyvalerate) with 2-hydroxyethyl methacrylate was collected. When the chemical pumps were stopped and the reactive extrusion was completed, the torsional force increased to about the level of the torsional force before the reactive extrusion was initiated. The changes observed in the torsional force during the experiment indicated the modification of the polymer and allowed an effective monitoring of the reactive extrusion process. No visible difference was observed between the extruded melt strands of the unmodified poly (-hydroxybutyrate-co-β-hydroxyvalerate) and the grafted poly (β-hydroxybutyrate-co-β-hydroxyvalerate).

Figure 2 shows a comparative proton NMR spectrum for unmodified poly (S-hydroxybutyrate-co-B-hydroxyvalerate) and poly (β-hydroxybutyrate-co-β-hydroxyvalerate) grafted with 2-hydroxymethacrylate. The peak characteristics for the 2-hydroxyethyl methacrylate monomer (CH3) was observed at 2.0 PPM. This confirmed the modification of the poly (B-hydroxybutyrate-co-B-hydroxyvalerate), but did not quantify the amount of 2-hydroxyethyl methacrylate grafted to the poly (β-hydroxybutyrate-co-B-hydroxyvalerate).

The melt rheology tests were carried out on the unmodified PHBV on a Goettfert 2,000 reograph available from Goettfert in Rock Hill, S.C. The modified PHBV of this example was prepared with 9% by weight of 2-hydroxyethyl methacrylate and 0.45% by weight of Lupersol®. The percentages by weight of 2-hydroxyethyl methacrylate and Lupersol® were based on the weight of the poly (β-hydroxybutyrate-co-hydroxyvalerate).

The melting rheology tests were carried out at 180 ° C with a matrix of 30/1 (length / diameter) mm / mm. The apparent melt viscosity was determined at apparent cut-off rates of 50, 100, 200, 500, 1000 and 2000 l / s.

The apparent melt viscosities at the various apparent cut-off rates were plotted and rheology curves for the unmodified PHBV and the PHBV grafted with 2-hydroxyethyl methacrylate from the example given above and were generated as shown in example 3. The results showed that the unmodified PHBV, over the full range of the cutting rates, had melting viscosities higher than the PHBV grafted with 2-hydroxyethyl methacrylate. Melt viscosity production was an indication of the chemical modification of PHBV due to reactive extrusion with 2-hydroxyethyl methacrylate.

Table 2 shows the data from a differential scanning calorimetry ("DSC") analysis of the PHBV and the PHBV samples grafted with 2-hydroxyethyl methacrylate.

Differential scanning calorimetry analysis of PHBV and PHBV grafted with 2-hydroxyethyl methacrylate.

Sample I.D. Fusion Peak-l Fusion Peak-2 (C °) Applied Melt (° C) Melt Control 150.75 159.20 84.04 g- 143.87 158.67 76.06 PHBV- 1 g- 148.37 157.99 74.53 PHBV-2 For PHBV samples grafted with 2- hydroxyethyl methacrylate, both melting point and melted enthalpy were observed to be decreased compared to unmodified PHBV. The changes observed in the thermal properties were an indication of the modified crystal structure and an indirect indication of the 2-hydroxyethyl methacrylate graft. In a previous reactive extrusion work, the melting peak and the enthalpy of the melt were also observed to decrease for the grafted polyethylene of 2-hydroxyethyl methacrylate.

Figure 4 shows a comparison between differential scanning calorimetry curves for PHBV and PHBV grafted with 2-hydroxyethyl methacrylate. Both curves showed 2 characteristic melting peaks. The curves exhibited the decrease in melt peaks and enthalpy of the melt observed for the PHBV grafted with 2-hydroxyethyl methacrylate in comparison to the unmodified PHBV. In addition to the decrease in melting peaks, the two melting peaks were further apart for the grafted PHBV samples. In addition, the relative proportion of the melting peak temperature above the melting peak of lower temperature was increased substantially after grafting, which showed that the properties of the two types of crystalline sizes were changed.

Example 2 Reactive Extrusion of Poly (butylene succinate) with 2-hydroxyethyl methacrylate The reactive extrusion process for grafting poly (butylene succinate) was carried out on both a Haake extruder as described in example 1 and on a ZSK-30 extruder with two different kinds of poly (butylene succinate); for example Bionolle® 1040 and Bionolle® 1020. The ZSK-30 extruder was a twin screw co-rotator, manufactured by Werner & Pfleiderer Corporation of Ramsey, New Jersey. The diameter of the extruder was 30 millimeters. 'The length of the screws was 13,088 millimeters. This extruder had 14 barrels, numbered consecutively from 1 to 14 from the supply hopper to the die. The first barrel, barrel No. 1, received poly (butylene succinate) and was not heated but cooled with water. The vinyl monomer, 2-hydroxyethyl methacrylate, was injected into barrel No. 5 and the peroxide Lupersol® 101 by Atochem was injected into barrel No. 6. Both the monomer and the peroxide were injected through an injector. nozzle under pressure. A vacuum port for devolatilization was included in barrel No. 11.

The reactive extrusion of poly (butylene succinate) differed significantly from the reactive extrusion of polylactide, poly (S-hydroxybutyrate-co- -hydroxy-valerate) or polyolefins. In fact, significant differences were observed between the reactive extrusions of the two different classes of poly (butylene succinate) carried out on the different extruders.

The reactive extrusion chemistry for the PBS graft is shown below: Reactive Extrusion Chemistry for Grafting Poly (Butylene Succinate) wherein x = -COOCH2CH2OH (HEMA) and -COO- (CH2CH20) n-C2Hs (PEG-MA) gives a mixture of: Initially, the extrusion conditions for the reactive extrusion of Bionolle® 1040 on the Haake extruder were determined. This polymer behaved very differently from polylactide and / or poly (-hydroxybutyrate-co-idroxivalerate). In fact, the properties of solid and melted state seemed very good, appearing more like polyolefins. Two samples of Bionolle® 1040 grafted with poly (ethylene glycol) methacrylate were produced in the Haake extruder. Table 3 given below showed the reactive extrusion process conditions for the experiments of Bionolle® 1040 grafted with poly (ethylene glycol) methacrylate in the Haake extruder.

Table 3 Reactive Extrusion Process Conditions to produce poly (butylene succxnate) grafted with poly (ethylene glycol methacrylate) in a Haake extruder.

The torsional force on the Haake extruder was monitored during the reactive extrusion of Bionolle® 1040 with poly (ethylene glycol) methacrylate. Figure 5 shows a time diagram against twisting during a reactive extrusion of both samples of Bionolle® 1040 grafted with poly (ethylene glycol) methacrylate. At the beginning of the reaction, when 4.6% poly (ethylene glycol) methacrylate and 0.29% peroxide were added, the torsional force was observed to decrease significantly. When the average torsional strength reached a stable state, the reaction product was determined as having stabilized and the sample was collected. When the chemical pumps were stopped and the reactive extrusion was completed, the torsional strength increased to the level before the modification. The same observations were made for 8.9% poly (ethylene glycol) methacrylate and 0.46% peroxide Lupersol® 101. Bionolle® 1040 samples grafted with poly (ethylene glycol) methacrylate appeared to have a lower viscosity in the melted yarns extruded No visible gels were observed and the solid properties of the yarns appeared similar to those of unmodified Bionolle® 1040.

The extrusion conditions were then determined for the reactive extrusion of Bionolle® 1040 on the ZSK-30 extruder. The unmodified Bionolle®1020 behaved similarly to the unmodified Bionolle®1040 on the Haake extruder. Four Bionolle®1020 samples grafted with 2-hydroxyethyl methacrylate were produced on the ZSK-30 extruder. The reactive extrusion experiments were designed to graft Bionolle®1020 with 2-hydroxyethyl methacrylate at low levels; for example of approximately 3% and 5%. Additionally, the effects of peroxide addition were studied at constant 2-hydroxyethyl methacrylate addition levels. Table 4 shows below the reactive extrusion process conditions for the experiments of Bionolle® 1020 grafted with 2-hydroxyethyl methacrylate.

Table 4 - Reactive Extrusion Process Conditions to produce Poly (butylene succinate grafted with polybutylene succinate grafted with 2-hydroxyethyl methacrylate on a ZSK-30 extruder.

The parameters of reactive extrusion, such as time, temperature, percent of torsion and matrix pressure were monitored on the extruder ZSK-30 during the reactive extrusion of Bionolle® 1020 with 2-hydroxyethyl methacrylate. Table 5 shows the process conditions during the reactive extrusion of each of the samples Bionolle®1020 grafted with 2-hydroxyethyl methacrylate. The percent torsional strength and melting temperature for each of the samples of Bionolle®1020 grafted with 2-hydroxyethyl methacrylate were equal to or greater than those of the unmodified Bionolle®1020.

Table 5 Process Conditions for Bionolle® 1020 Reactive Extrusion with Hydroxyethyl Ethacrylate on the ZSK-30 Extruder ZSK Run Sheet Kimberly-Clark Resin Operators: Bionolle® 1020 DMS, GJW Pump 1: Hydroxyethyl Methacrylate Date / Time Pump 2: Lupersol 101 8/4/97 9:30 AM Comments Control sample 9:54 19.91 0.00 0.00 290 48 3 180 178 180 180 160 164 168 184 105 10:00 20.07 0.00 0.00 299 48 3 174 185 180 180 171 160 169 182 105 Sample # 1, 4.7p% Hydroxyethyl methacrylate and 0.50% Lupersol 101 11:44 19.99 0.94 0.10 300 47 3 177 179 180 180 170 160 147 164 107 11:50 19.99 0.94 0.10 299 49 3 181 180 180 180 170 160 148 165 94 11:54 19.91 0.94 0.10 299 47 3 174 179 180 180 170 160 147 165 101 Sample # 2, 3.1% Hydroxyethyl methacrylate and 0.23% Lupersol 101 12: 16 19.99 0.62 0.046 1299 52 3 177 181 179 181 170 160 149 167 110 12: 30 19.99 0.62 0.046 | 300 50 3 175 182 179 180 170 160 149 167 132 Sample # 3, 30.0% Hydroxyethyl methacrylate and 1.0% Lupersol 101 12: 51 19.99 0.58 0.20 300 54 4 183 182 180 180 170 160 149 168 178 12: 58 19.99 0.62 0.20 299 57 4 175 180 180 180 170 160 149 168 181 Sample # 4, 3.0% Hydroxyethyl methacrylate and 1.2% Lupersol 101 13:06 19.91 0.60 0.24 I 299 58 4 181 181 180 180 170 159 148 168 335 13: 14 20.07 .060 0.24 1300 60 4 174 180 179 180 170 160 149 168 306 As the level of peroxide initiator Lupersol®101 was increased to 1.0% with the level of 2-hydroxyethyl methacrylate constant at 3.0%, the melt viscosity increased dramatically. The melt pressure almost doubled compared to the unmodified Bionolle®1020 from 107 pounds per square inch to 180 pounds per square inch. The melted threads were much thicker and the polymer appeared to have undergone some cross-linking. When the Lupersol®101 was increased to 1.2% with the level of 2-hydroxyethyl methacrylate at 3.0%, the evidence of cross-linking was even more evident. The extruded yarns showed a dramatic melt fracture and the melt pressure increased even more, compared to the unmodified Bionolle®1020, to about 306 pounds per square inch. The experiment was discontinued at that point and a sample at the 1.2% peroxide level could not be collected. The dramatic changes in the properties of Bionolle®1020 grafted with 2-hydroxyethyl methacrylate at low levels of monomer and higher levels of peroxide are thought to be due to a complete cross-linking reaction. The reason for the crosslinking reaction was not observed for the Bionolle®1040 grafted with poly (ethylene glycol methacrylate) on the Haake extruder is believed to be due to one or more of the following factors: (1) a different extruder (including different configuration) of screw and dwell time), (2) different polymer (120 had a viscosity greater than 1040), (3) different monomer, and (4) more significantly a lower peroxide level.In the previous reactive extrusion experiments with both polyethylene or polyethylene oxide, as the relative reactive level was increased, the increased crosslinking amount resulted in an increased level of observed gels and melted fracture.

The significant differences in the polymer, monomer, extruder and process conditions made it difficult to compare Bionolle®1040 grafted with poly (ethylene glycol) methacrylate and on the Haake extruder and Bionolle®1020 grafted with 2-hydroxyethyl methacrylate on the extruder ZSK-30. However, the significance of this series of experiments with the Bionolle®1020 grafted with 2-hydroxyethyl methacrylate was that the reactive extrusion and polymer properties were significantly different from each of the previous biodegradable reactive extrusion experiments, with polylactides, poly (-hydroxybutyrate-co-phé-hydroxyvalerate), or poly (butylene succinate) on the Haake extruder.

Figure 6 shows a comparative proton NMR spectrum for the unmodified Bionolle®1040 and grafted from a reactive extrusion onto the Haake extruder. The characteristic peak for the grafted poly (ethylene glycol) methacrylate (CH3) monomer was observed at 1.0 parts per million. The level of grafting of poly (ethylene glycol) methacrylate was determined as being poly (butylene succinate).

The melting rheology was studied for unmodified Bionolle® 1,020 and 1040, Bionolle®1040 grafted with poly (ethylene glycol) methacrylate over the Haake extruder and Bionolle® 1020 grafted with 2-hydroxyethyl methacrylate over the ZSK extruder. The measurement was carried out on a Goettfert capillary rheometer at 180 ° C following the procedure described in the experimental section.

Figure 7 shows the melt rheology curves for the unmodified Bionolle®1040 and the Bionolle grafted with poly (ethylene glycol) methacrylate 1040 on a Haake extruder. The results showed that Bionolle®1040 grafted with poly (ethylene glycol) methacrylate over the full range of cutting rates, had a lower melt viscosity than that of non-grafted Bionolle®1040. In fact, as the amount of poly (ethylene glycol) methacrylate was increased from 4.5% to 9%, the melt viscosity was further decreased. The results were similar to the results of the polylactide graft and of poly (β-hydroxybutyrate-co-S-hydroxyvalerate). The observed decrease in the melt viscosity of Bionolle®1040 grafted with poly (ethylene glycol) methacrylate with increasing amounts of monomer added was similar to the effects observed for poly (ethylene glycol) methacrylate grafted polypropylene and polyethylene at work of pre-reactive extrusion.

Figure 8 shows the melt rheology curves for the unmodified Bionolle®1020 and the Bionolle®1020 grafted with 2-hydroxyethyl methacrylate on the ZSK-30 extruder. The melting rheology properties of the grafted material correlated with the reactive extrusion properties observed. The 5% sample of 2-hydroxyethyl methacrylate, at a relatively low peroxide level, showed a slight increase in the melt viscosity compared to the unmodified Bionolle® 1020. Both of the 3% 2-hydroxyethyl methacrylate samples showed an increased melt viscosity compared to the unmodified Bionolle®1020. The 3% samples of 2-hydroxyethyl methacrylate also showed an increased melt viscosity with increased peroxide addition levels, resulting from the cross-linking of the Bionolle®1020 polymer. The 3% sample of 2-hydroxyethyl methacrylate at a peroxide addition of 1.2% could not be collected, so the melting rheology data were not collected.

Table 6 showed the data for the differential scanning calorimetry analysis of the samples of Bionolle® unmodified 1040 and of Bionolle®1040 grafted with poly (ethylene glycol) methacrylate produced on a Haake extruder.

Table 6-Differential Scanning Calorimetry Analysis of Bionolle 1040 and Bionolle®1040 grafted with poly (ethylene glycol) methacrylate.

Table 7 shows the differential scanning calorimetry data for the unmodified Bionolle®1020 and Bionolle®1020 samples grafted with 2-hydroxyethyl methacrylate produced on a ZSK-30 extruder.

Table 7-Scanning Calorimetry Analysis' Differential of Bionolle®1020 and Bionolle®1020 grafted with 2-hydroxyethyl methacrylate.

The Bionolle®1040 grafted with poly (ethylene glycol) methacrylate on the Haake extruder showed an increase in the melting peak compared to the unmodified Bionolle®1040. This result was unexpected because typically, the grafted polymers have shown a decrease in melting peak with the graft. Figure 9 shows a comparison between differential scanning calorimetry curves for unmodified Bionolle®1040 and Bionolle®1040 grafted with poly (ethylene glycol) methacrylate.

Bionolle®1020 grafted with 2-hydroxyethyl methacrylate on the ZSK-30 extruder showed both a decrease in melting peak and melted enthalpy compared to unmodified Bionolle®1020. Figure 10 shows a comparison between the differential scanning calorimetry curves for the non-grafted Bionolle®1020 and the Bionolle®1020 grafted with 2-hydroxyethyl methacrylate. The changes observed in the thermal properties were an indication of the modified crystal structure and an indirect indication of the 2-hydroxyethyl methacrylate graft. The decrease observed in the melting peak and the enthalpy of the melt was more typical of the grafted polymers, such as poly (S-hydroxybutyrate-co-E-hydroxyvalerate) grafted with 2-hydroxyethyl methacrylate or the polyester work grafted with 2-hydroxyethyl methacrylate. -hydroxyethyl methacrylate previous.

Example 3 Reactive Extrusion of Polycaprolactones with 2-hydroxyethyl methacrylate This example shows the process of reactive extrusion to make grafted polycaprolactones. The same twin screw extruder ZSK-30 which in the aforementioned example 2 was used. Tone® P-787 polycaprolactones were fed to the feed throat of the twin screw extruder ZSK-30 at a rate of 20 pounds / hour. The 2-hydroxyethyl methacrylate was fed to barrel # 5 at a rate of 0.36 pounds / hour (1.8% by weight of the polycaprolactone resin) and the peroxide Lupersol® 101 was fed to barrel # 6 at a rate of 0.03 pounds / hour (0.15% by weight of the polycaprolactone resin). The screw speed was 300 revolutions per minute.

The following temperatures were recorded during this grafting process: The melting temperature was 214 ° C. The melt pressure measured was 422 pounds per square inch. Vacuum over the vent hole (over barrel # 11) was 24.49 inches Hg to remove unreacted 2-hydroxyethyl methacrylate monomer.

The resulting grafted polycaprolactones are cooled in water and made into pellets in white pellets. The grafted polycaprolactone strands were strong and ductile. The surface of the threads and the pellets was brilliant.

The film setting of the grafted polycaprolactones was carried out on a Haake twin screw extruder described in Example 1 endowed with an 8-inch film matrix (per Haake). The film was cooled by means of a cooling roller cooled with water at room temperature. The extruder had four heating zones with temperatures set at 120 ° C, 130 ° C, 130 ° C, 140 ° C, respectively. The screw speed was 40 revolutions per minute. The extruder was fed by flooding with the grafted polycaprolactones. The measured melting temperature was 136 ° -137 ° C. The melt pressure was in the range of 800 to 1100 pounds / square inch. Thin films of about 1.5 thousandths in thickness were obtained. The grafted polycaprolactone film was strong, bright and ductile. The film was clear and transparent. The grafted polycaprolactone film had significantly improved film clarity as compared to a film made from the unmodified polycaprolactone which was opaque.

The grafted polycaprolactone melt was stickier than a non-grafted polycaprolactone which indicated a potential as an adhesive for hot melt uses.

Example 4 Films that respond to water of Biodegradable Polymer and Water Soluble Polymer The twin screw extruder ZSK-30 described in example 2 was used to make a series of mixtures of biodegradable polymer and water soluble polymer.

The first series of experiments used Bionolle®1020 poly (butylene succinate) as the biodegradable polymer. Polyvinyl alcohol was used as the water soluble polymer.

The control of polyvinyl alcohol (Airfoil®203 from Air Products) was extruded at a rate of 20 pounds per hour. The extruder temperatures were set at 110 ° C in zone 1 and 150 ° C in zones 2 and 3, 160 ° C in zone 4, 170 ° C in zone 5, and 180 ° C in the zone 6 and 7. The melting temperature was 199 ° C. The melt pressure was 197 pounds per square inch. The screw speed was 300 revolutions per minute. The film produced was clear and soluble in water.

The same conditions described above for the control were used to extrude samples of polymer blends of polybutylene succinate Bionolle®1020 and polyvinyl alcohol Airbol® 203 were fed separately from the extruder by means of two gravimetric feeders to produce a mixture of 80% by weight of polyvinyl alcohol and 20% by weight of poly (butylene succinate) .The melt pressure was 174 pounds per square inch.The melting temperature was 199 ° C. The extruded yarns were smooth and very well-trained Example 5 Films that respond to biodegradable polymer water and a water soluble polymer.

The same procedure was followed as in example 4 indicated above, except that poly (butylene succinate) and polyvinyl alcohol were supplied at a rate such as to produce a mixture of 70% by weight of polyvinyl alcohol and 30% by weight of polyvinyl alcohol. poly (butylene succinate). The melt pressure was 192 pounds per square inch. The melting temperature was 198 ° C. The extruded threads were smooth and well formed.

Example 6 Films that respond to Biodegradable Polymer water and a Water Soluble Polymer.

The same procedure was followed as in example 4 given above except that poly (butylene succinate) and polyvinyl alcohol were fed at a rate such as to produce a mixture of 60% by weight of polyvinyl alcohol and 40% by weight of poly. (butylene succinate). The melt pressure was 202 pounds per square inch. The melting temperature was 197 ° C. The extruded threads were smooth and well formed. The extruded polymer yarns were then converted into pellets.

Example 7 The pellets made in Examples 4 to 6 were made Films made from Mixtures comprising Polyvinyl Alcohol and Poly (butylene succinate).

The pellets made in Examples 4 to 6 were made into films by means of a melt extrusion setting process using a Haake twin screw extruder, as described in Example 1. The extruder was set at temperatures for the 4 hours. areas as follows: 170 ° C, 180 ° C, 180 ° C and 190 ° C. The screw speed was 100 revolutions per minute. The films produced were 1 thousandth of an inch in thickness.

The films produced from the pellets of example 4 were dispersible in water in 2 minutes in water at 22 ° C. The films produced using the pellets of example 5 were dispersed in water within 2 minutes in water at 22 ° C. The films produced using the pellets of example 6 were dispersed in water in 2 minutes in water at 22 ° C.

Example 8 Mixtures of modified biodegradable polymer and modified water soluble polymer.

The same twin screw ZSK-30 described in the previous example was used for the following example. Two gravimetric feeders were used to supply two different polymers simultaneously to the extruder supply throat. The polycaprolactone and a water soluble polymer from National Starch and Chemical Company, of Bridgewater, New Jersey, having the designation NS 70-4442. NS 70-4442 is a sulfonated polyester polymer soluble in water. The polycaprolactone was fed to the extruder at a delivery rate of 16 pounds per hour; The S70-4442 was supplied at a rate of 4 pounds per hour. The delivery rates produced a polycaprolactone: NS 70-4442 ratio of 80:20 by weight. The 2-hydroxyethyl methacrylate was injected into barrel # 5 by an Eldex pump at a rate of approximately 0.4 pounds / hour. The Lupersol® 101 was injected into barrel # 6 at a rate of 0.032 pounds per hour by an Eldex pump. The screw speed was 300 revolutions per minute. The temperatures were: The measured melting temperature was 209 ° C. The melt pressure was 258 pounds per square inch. The yarns were cooled on a conveyor belt cooled by a fan and subsequently pellets were made. The threads and the pellets had smooth surfaces.

The set films were made from the pellets on a Haake twin screw extruder as previously described. The film showed sensitivity to water; for example a grid is reduced an increased deformability and smoothness.

Example 9 Mixtures of modified biodegradable polymer and modified water soluble polymer.

The same procedure as described in Example 8 was followed except that the delivery rates were 18 pounds per hour for polycaprolactone and 12 pounds per hour for NS 70-4442 which occurred at a polycaprolactone: NS 70 ratio. -4442 from 60:40 by weight. The temperatures were: The melting temperature was 210 ° C. The melt pressure was 158 pounds per square inch. Films made from the mixed composition were sensitive to water. The water sensitivity of the films was improved by increasing the amount of NS 70-4442 in the mixture, thereby rendering the film dispersible in water or disintegrable in water.

Example 10 Polylactide (PLA) was supplied by Aldrich Chemical Company, catalog # 43232-6. Poly (butylene) succinate (PBS) was supplied by Showa Highpolymer Company under the trade name Bionolle® 1020. Polyvinyl alcohol (PVOH) was supplied by Nippon Gohsei under the trade name Ecomaty® AX10000.

Polylactides grafted with 2-hydroxyethyl methacrylate were used. The grafted polylactide was produced by reactive extrusion on a twin screw extruder Werner & Pfleiderer ZS -30. The process for making the polylactide grafted is described in the previous examples. 2-Hydroxyethyl methacrylate (HEMA) and polyethylene glycol ethyl ether methacrylate (PEG-MA) with a molecular weight of 245 g / mol, both supplied by Aldrich Chemical Company were used as reactive polar vinyl monomers. The peroxide initiator used was Lupersol® 101, supplied by Atochem.

The blends were produced using a Rheomix® 600 twin roller mixer (manufactured by Haake). The mixer had three heating zones, one for the front plate, for the mixing chamber and for the back plate. The temperatures of the zones, the speed of the screw and the time of mixing were controlled by computer.

A typical polymer mixing experiment on the Haake mixer was carried out as follows: the mixer was preheated to 180 ° C. A specified amount of polylactide or grafted polylactide and polyvinyl alcohol was added to the mixer and the material was mixed for 5 minutes at a screw speed of 150 revolutions per minute. After 5 minutes, the melted was removed from the mixer and cooled in the air.

The blends were also produced using the T-100 screw extruder (manufactured by Haake) with 3 barrels and 300 mm processing length. The unit contained a set of conical twin screws, custom made counter-rotators. The supply section was not heated and cooled with water. The extruder had three heating sections designated as zone 1, zone 2 and zone 3 from the supply section to the die. The matrix was designated as zone 4. The matrix had two openings of 3 mm in diameter which were separated by 10 mm.

A typical polymer mixing experiment on the Haake extruder was carried out as follows: the heating zones were preheated to 170 °, 180 °, 180 ° C. The extruder was set at 150 revolutions per minute. The pellets of the polylactide or the grafted polylactide were mixed at a specific ratio with the polyvinyl alcohol pellets. The mixture of the resin pellets was continuously cooled twice and pelleted twice.

In contrast to the two-step approach, a novel process for the development of biodegradable and disposable polymer was developed in which only one extrusion step was employed. This process is called reactive mixing. In the reactive mixing process, a biodegradable polymer and a water soluble polymer are mixed while these are reactive grafted with the polar monomer. At the end of the extruder, the melt is extruded, cooled and pelletized.

The reaction mixture had the potential to contain one or more of several unreacted and reacted products.

Some of the unreacted and water-soluble biodegradable polymer may remain in the final reactive mixture. Biodegradable grafted and water soluble polymers are possible reaction products in the reaction mixture. Also, the reactive mixture may contain some water-soluble and biodegradable reactively connected polymers, which may be novel compositions of matter.

Compared to the two-step process, the single pass reactive mixing process offers a number of advantages and benefits: 1) it is a lower cost process since only one cycle of extrusion, cooling and pelletizing is required, rather than two; 2) reduces polymer degradation due to one less extrusion step; and 3) causes less variation in the polymer blend composition and in the quality of the resulting mixtures.

The reactive mixing was carried out on a twin screw extruder Haake TW-100 described above. A typical reactive mixing experiment on the Haake extruder was carried out as follows: the heating zones were previously heated to 160 °, 180 °, 180 °, 190 ° C. The extruder was set at 150 revolutions per minute. Poly (butylene succinate) pellets were mixed at a specified ratio with polyethylene oxide pellets. The mixture of the resin pellets was supplied to the Haake extruder with a volumetric feeder at a rate of 5 pounds per hour. Poly (ethylene glycol) methacrylate was added to the supply section at 0.40 pounds per hour and Lupersol® 101 was added to the supply section at 0.025 pounds per hour. After adding poly (ethylene glycol) methacrylate and Lupersol® 101, the torsional force decreased and then stabilized. The process was allowed to reach equilibrium and the extruded yarns were cooled in the air and pelleted.

The reactive mixtures of poly (butylene succinate) and polyethylene oxide with poly (ethylene glycol) methacrylate were converted to thin films using the Haake extruder described above, except that a 4 inch by 8 inch slit matrix was used instead of a two-wire matrix. A cooled coiling roll maintained at 15 ° -20 ° C was used to collect the film. Adjustments in matrix spacing, screw speed and winding speed were used to optimize film processing and film thickness.

A typical film conversion run on the Haake extruder was carried out as follows: the selected reaction mixture pellets were fed by flooding into the feed section. The temperature profile for the four heating zones was 170 ° C, 180 ° C, 180 ° C and 190 ° C. The temperature of melted in the matrix was 195 ° C. The screw speed was 30 revolutions per minute. The winding speed was 70% of the maximum. The process conditions were adjusted to produce a film thickness of approximately 4 mils. The process was allowed to stabilize and the pellet was collected.

Dry stress tests were carried out on a Syntech l / D tension tester under the following conditions: measuring length-30 mm, cross-speed-4 mm / s, narrow width of dog bone 3.18 mm. Wet tension tests were also carried out on the Syntech l / D tension tester under the same conditions, except that the films were submerged under water during the test. A water tank was used for the wet tension tests. The maximum tension, the percent of breaking stress, the energy at break (area under tension against the stress curve), and the modulus were calculated for each film test and the percent loss in stress properties from dry to wet was determined.

Differential scanning calorimetry was carried out on a TA Instruments differential scanning calorimetry 2910. 10-15 milligrams of film sample were used for each test. The following method was carried out for each test: 1-equilibrate at -20 ° C, 2-isothermal for 1 minute, 3-ramp at 20 ° C / min. At 200 ° C, 4-ramp, 30 ° C / min. At 30 ° C. The melt rheology tests will be carried out on a 2003 Goettfert reograph with 30/1 mm L / D at 195 ° C (the melting temperature observed for most film conversion runs). The apparent viscosity for each material was determined at apparent cut-off rates of 50, 100, 200, 500, 1000, 2000 s. "1 A rheology curve was drawn for each material of apparent viscosity against cut-off rate.

The wet tensile properties of the physical and reactive mixtures of poly (butylene succinate / polyethylene oxide) were tested and compared with the dry stress properties. Table 8 and Table 9 show the dry and wet tensile properties for the films of physical and reactive mixtures of 20/80, 30/70 and 40/60, respectively. The percent loss in tension properties from dry to wet for stress, strain, rigidity and firmness was also recorded. Mixtures of 50/50 and 60/40 were sensitive to water, but were not included because they did not significantly lose the tension properties in the water.

Table 8-Dry and wet tension properties of Poly blend films (butylene succinate / polyethylene oxide) Percent Dry to Moist Loss Table 9 - Properties of Dry and Humid Tension of Films of Physical Reactive Mixing of Poly (butylene succinate / polyethylene oxide) Percent loss from dry to wet Tension 58% 0% -82% resistance 94% 86% 36% Firmness 98% 86% -25% Rigidity 96% 91% 83% For compositions of 20/80 and 30/70, Reactive mixtures lost a greater percentage of dry to wet tensile properties which is very desirable for waste disposal applications. The relative loss in tension properties from dry to wet was obviously improved for the reactive mix film.

Surprisingly, the physical and reactive poly (butylene succinate / polyethylene oxide) 40/60 blends showed an increased percent stress at breaking. Additionally, the 30/70 physical mixture of poly (butylene succinate) / polyethylene oxide showed an increase in tensile stress at breaking. In fact, when these mixtures were exposed to water, the films appeared to have somewhat elastomeric properties. These observations were very surprising because similar mixtures of other polymer systems always showed a decrease in tensile properties after most of the water-soluble component dissolved in the water. The plasticizing effects due to the hydration of polyethylene oxide, the only "layered" morphology of the physical and reactive mixtures of poly (butylene succinate) and polyethylene oxide have contributed to the unique wet tensile properties of these mixtures . The elastomeric properties of the reactive mixtures can still show the potential for development as a packing for a notch improvement, while still being disposable with water discharge.

Figures 11 and 12 show SE (electron scanning microscopy) images of the topological morphology of the fracture surface of 60/40 reactive and physical polysaccharide (polybutylene succinate) / polyethylene oxide films. In Figure 11, a two-phase microstructure was observed for the physical mixture. The adhesion between the continuous phase of poly (butylene succinate) and the dispersed phase of polyethylene oxide was very poor, as was shown by the presence of the holes left by the polyethylene oxide particles which are pulled out of the poly (butylene succinate) in the interface of the two phases. In Figure 12, the compatibility of poly (butylene succinate) and polyethylene oxide was dramatically improved for the reaction mixture. In fact, no second phase is visible in the electron microscopy photomicrograph of the reactive mix film. This observation suggests either superior compatibility or possibly even miscibility of poly (butylene succinate) and polyethylene oxide with reactive mixing.

The observed improvement in mixing compatibility and reactive mixing was further supported by the composition mapping of the same fracture surfaces of physical and reactive 60/40 films of poly (bu binocyanate succinate) / polyethylene oxide by medium of BEI (electronic imaging scattered-posterior). The BEI images are shown in Figures 13 and 14. The phase with a higher average atomic number, the poly (butylene succinate) phase, showed a brighter image in the photomicrograph. The polyethylene oxide phase, with a lower average atomic number, appeared as the dark phase. In Figure 13, the polyethylene oxide phases were easily visible through the physical blend film, ranging from 1 to 3 microns in size. However, in Figure 14, a polyethylene oxide phase over 95% of the total image area for the reactive mix film was not visible (even though the polyethylene oxide is 40% of the mixture). Only a few dark particles, possibly due to polyethylene oxide, were observed in the image.

Analysis of the thermal properties of the physical and reactive mixtures of poly (butylene succinate) / polyethylene oxide by differential scanning calorimetry (DSC) was carried out using the following procedure. The differential scanning calorimetry was carried out on a TA Instruments 2910 differential scanning calorimeter. 10-15 mg. Sample films were used for each test. The following method was followed for each test: (1) equilibrate at -20 ° C, (2) isothermal for 1 minute, (3) ramp at 20 ° C / min. At 200 ° C (4) ramp at 30 ° C / min at 30 ° C / min at 30 ° C. Table 10 showed the data from the differential scanning calorimetry analysis.

Table 10-Differential Exploration Calorimetry Analysis of Physical and Reactive Mixtures of Poly (Butylene Succinate) / Polyethylene Oxide For the reactive mixtures, both melting peaks (Tj and melting enthalpy (^ H) were observed to decrease compared to the physical mixtures at the same weight ratios.In addition, the melting peaks for the polyethylene oxide phase of the reactive mixtures of poly (butylene succinate / polyethylene oxide) were observed to decrease with the increased polyethylene oxide content in the mixtures.The observed changes in thermal properties were an indication of the modified crystal structure and the indication indirect of the graft.

Figure 15 showed the observed decrease in Tm for the polyethylene oxide phase of the reactive mixtures of poly (butylene succinate) / polyethylene oxide as the percent of polyethylene oxide in the mixtures was increased. Figure 16 shows an increase in the change of: Tm (^ Tm) for the reactive mixtures compared to the physical mixtures as the percent of polyethylene oxide in the mixtures is increased.

Figure 17 shows a comparison between differential scanning calorimetry curves for physical and reactive 30/70 mixtures of poly (butylene succinate) / polyethylene oxide. Both curves showed two characteristic melting peaks, the first for polyethylene oxide and the second for poly (butylene succinate). The curves exhibited the decrease in Tra and in fi for the polyethylene oxide and poly (butylene succinate) components.

The melt rheology was studied for the physical and reactive mixtures of poly (butylene succinate) / polyethylene oxide on a Goettfert capillary rheometer at 195 ° C using the following procedure. The melt rheology tests were carried out on a Goettfert 2003 rheometer with a matrix of 30/1 mm L / D at 195 ° C (the melting temperature observed for most film conversion runs). The apparent melt viscosity for each material was determined at apparent cut-off rates of: 50, 100, 200, 500, 100, 200 s "1. A rheology curve was plotted for each apparent viscosity material against cut rate. Apparent Figure 18 shows the melt rheology curves of the physical and reactive 20/80 and 60/40 mixtures of poly (butylene succinate) / polyethylene oxide, as well as the melting rheology curve for poly (succinate) of butylene) alone. The results showed that the physical mixtures, over the full range of the cutting rates, had a higher melting viscosity than the reactive mixtures. Additionally, with the larger amounts of poly (butylene succinate), the melt viscosity was reduced in both physical and reactive mixtures. The observed decrease in the melt viscosity of the reactive mixtures was expected to be due to the lubrication effects of the grafted and unreacted poly (ethylene glycol methacrylate) as well as the reduction in molecular weight and improved compatibility due to the reactive mixing. The reduction in melt viscosity was an indirect indication of the chemical modification of poly (butylene succinate) and / or polyethylene oxide due to reactive mixing with poly (ethylene glycol) methacrylate. The reduction in melt viscosity with the increase in poly (butylene succinate) composition was unexpected due to the lower viscosity of poly (butylene succinate) compared to polyethylene oxide, due to the low melt viscosity of the mixtures reactive, fiber spinning may be a possibility for additional applications of poly (butylene succinate) / polyethylene oxide reactive mixtures.

Example 11 As shown in example 1, the grafting of poly (p-hydroxybutyrate-co-p-co-hydroxyvalerate) with 2-hydroxyethyl methacrylate by a continuous reactive extrusion process is not practical because the β (β -hydroxybutyrate-co- -co-hydroxyvalerate) grafted does not solidify or crystallize at a sufficient rate. The following example shows how the grafted poly (β-hydroxybutyrate-co-p-co-hydroxyvalerate) can be modified so that it can be produced by a continuous reactive extrusion process.

The same Haake twin counter screw extruder was used as in example 1. The four temperature zones were set at 170 °, 200 °, 190 ° and 190 ° C, respectively. The screw speed was 150 revolutions per minute. A mixture of polylactides and poly (p-hydroxybutyrate-co-p-co-hydroxyvalerate) in a weight ratio of 1: 1 was fed into the extruder with a volumetric feeder at a rate of 5.0 lb / hr. The (? -hydroxybutyrate-co-p-co-hydroxyvalerate) was the same as that used in Example 1. Polylactide was purchased from Aldrich Chemical Company of ilwaukee, Wisconsin (Aldrich catalog No. 42232-6). The polylactides were a biodegradable polymer and had a number average molecular weight of approximately 60000 g / mo. And a weight average molecular weight of approximately 144,000 g / mol. The monomer of 2-hydroxyethyl methacrylate and Lupersol® 101 were injected into the extruder at yields of 0.5 pounds per hour and 0.025 pounds per hour respectively. The 2-hydroxyethyl methacrylate and Lupersol® 101 were the same as used in Example 1. The extruded wires solidified rapidly and were easily pelleted directly.

Example 12 The same extrusion and process conditions as those of Example 11 were used, except that the supply rate of the polymer mixture was increased to 8.7 lb / hr. Even at this high extrusion rate, the extruded yarns solidified rapidly and were easily pelletized directly.

Example 13 The same process and extrusion conditions as in Example 12 were used, except that the butylacrylate was replaced by 2-hydroxyethyl methacrylate. Butyl acrylate was fed at a rate of 0.86 lb / hr. and the Lupersol® 101 was fed at a rate of 0.04 lbs / hr. The extruded wires solidified quickly and were pelletized easily and directly.

Example 14 The same procedure was followed as in example 11, except that the temperature zones were set at 170 ° C, 180 ° C, 180 ° C and 190 ° C respectively. In addition, the polyethylene oxide was replaced by the polylactide. A mixture of polyethylene oxide and poly (β-hydroxybutyrate-co-β-co-hydroxyvalerate) in a weight ratio of 50:50 was fed to the extruder with a volumetric feeder at a throughput of 5.0 lbs / hr. The polyethylene oxide was the same as used in Example 10. The 2-hydroxyethyl methacrylate monomer and Lupersol® 101 were injected into the extruder at 0.5 lbs / hour and 0.025 lb / hour respectively. The extruded yarns solidified rapidly and were easily pelletized directly. Example 15

Claims (33)

The same procedure was followed as in example 14, except that the poly (ethylene glycol methacrylate) was replaced by 2-hydroxyethyl methacrylate. The extruded yarns solidified rapidly and were easily pelletized directly. It is understood that these examples are illustrative embodiments and that this invention should not be limited by any of the examples or details of the description. Rather, the appended claims should be considered as widely constructed within the scope and spirit of the invention. R E I V I N D I C A C I O N S

1. A homogenous polymer mixture composition responsive to water comprising a biodegradable polymer grafted with a monomer, oligomer or polar polymer or a combination thereof and a water soluble polymer or a water soluble polymer grafted with a monomer, oligomer or polar polymer or a combination thereof.

2. The composition as claimed in clause 1, characterized in that said biodegradable polymer is selected from poly (hydroxyalkanoate), poly (alkylene succinates), polycaprolactones or mixtures thereof which are hydrolytically degradable.

3. The composition as claimed in clause 1, wherein said biodegradable polymer is selected from poly (hydroxybutyrate-co-fi-hydroxyvalerate), poly (ethylene succinate), poly (butylene succinate), polycaprolactone or mixtures the same.

4. The composition as claimed in clause 1, wherein said polar vinyl monomer is a polymerizable ethylenically xnsaturado containing at least one polar functional group or said oligomer or said polymer is an oligomer or polymer powder of an ethylenically unsaturated monomer which contains at least one polar functional group.

5. The composition as claimed in clause 4, characterized in that said at least one polar functional group is a hydroxyl, carboxyl, cyano, amino, sulfonate group or a combination thereof.

6. The composition as claimed in clause 3, characterized in that said at least one polar functional group is a hydroxyl group.

7. The composition as claimed in clause 1, characterized in that said polar monomer is a polar vinyl monomer.

8. The composition as claimed in clause 1, wherein said monomer polar is selected from poly (ethylene glycol) acrylates, poly (ethylene glycol) alkyl acrylates ether, poly (ethylene glycol) methacrylates, poly (ethylene glycol) alkyl ether methacrylates, acrylic acid, maleic anhydride, itaconic acid, sodium acrylate, 3-hydroxypropyl methacrylate, 2-hydroxyethyl methacrylate, 3-hydroxypropyl acrylate, 2-hydroxyethyl acrylate, acrylamide, gliciril methacrylate, 2-cyano ethyl acrylate, gliciril acrylate, 4 nitrophenyl acrylate, pentabromophenyl acrylate, poly (propylene glycol) methacrylates, poly (propylene glycol) acrylates, 2-propene-l-sulphonic acid and its sodium salt, 2-sulfoethyl acrylate, sulfoethyl methacrylate 2-3-sulfopropyl acrylate, 3 -sulfopropyl methacrylate or mixtures thereof.

9. The composition as claimed in clause 1, characterized in that said monomer, oligomer or polar polymer is selected from 2-hydroxyethyl methacrylate, polyethylene glycol methacrylate or analogs thereof.

10. The composition as claimed in clause 1, characterized in that said monomer, oligomer or polar polymer is 2-hydroxyethyl methacrylate or its derivatives.

11. The composition as claimed in clause 1, wherein said monomer, oligomer or polar polymer is selected from 2-hydroxyethyl methacrylate, polyethylene glycol methacrylate or analogs thereof and said biodegradable polymer is selected from poly (ß, hydroxybutyrate co-hydroxyvalerate), poly (ethylene succinate), poly (butylene succinate), polycaprolactone or mixtures thereof.

12. The composition as claimed in clause 1, characterized in that said biodegradable polymer contains from 1 to 20 weight percent monomer, oligomer or polar polymer or a combination thereof.

13. The composition as claimed in clause 1, characterized in that said water-soluble polymer is selected from said polyethylene oxide, polyvinyl alcohol, hydroxypropylcellulose or polyacrylic acid.

14. The composition as claimed in clause 1, characterized in that said biodegradable polymer is selected from poly (hydroxyalkanoates), poly (alkylene succinates), polycaprolactones or mixtures thereof, and said monomer, oligomer or polar polymer is selected from 2-hydroxyethyl methacrylate, polyethylene glycol methacrylate or analogs thereof and said water soluble polymer is selected from polyethylene oxide of polyvinyl alcohol, sulfonated polyester, hydroxypropylcellulose, polyacrylic acid or polyacrylamide.

15. A polymer mixture that can be dispersed in homogeneous water comprising from 1% to 35% by weight of a grafted biodegradable polymer and from 65% to 99% by weight of a water soluble polymer or an water soluble polymer inert .

16. A polymer blend that can be disintegrated in homogeneous water comprising from 35% to 45% by weight of a biodegradable grafted polymer and from 55% to 65% by weight of a water soluble polymer or a water-soluble polymer grafted .

17. A mixture of weakened polymer in homogeneous water comprising from 45% to 55% by weight of a biodegradable grafted polymer and from 45% to 55% by weight of a water-soluble polymer or of a water-soluble polymer injected.

18. A film comprising the composition as claimed in clause 1.

19. A fiber comprising the composition as claimed in clause 1.

20. An article that comprises the composition as claimed in clause 1.

21. A method for making a selectively homogeneous water-sensitive polymer blend composition comprising the steps of: combining a grafted biodegradable polymer with a monomer, oligomer or polar polymer or a combination thereof and a water soluble polymer at a temperature above the melting temperature of a water soluble polymer and below the decomposition temperature of the soluble polymer in water under a high cut; Y mixing said combination to form a homogenous polymer blend composition.

22. The method as claimed in clause 21, characterized in that said biodegradable polymer is selected from poly (hydroxyalkanoate), poly (alkylene succinates), polycaprolactones or mixtures thereof which are hydrolytically degradable.

23. The method as claimed in clause 21, characterized in that said biodegradable polymer is selected from poly (phé-hydroxybutyrate-co- -hydroxyvalerate), poly (ethylene succinate), poly (butylene succinate), polycaprolactone or mixtures of the same.

24. The method as claimed in clause 21, characterized in that said polar monomer is an ethylenically unsaturated monomer containing at least one polar functional group or said oligomer or said polymer is an oligomer or a polymer polymer of an ethylenically unsaturated monomer which contains at least one polar functional group.

25. The method as claimed in clause 21, characterized in that said at least one polar functional group is a hydroxyl, carboxyl, sulfonate group or a combination thereof.

26. The method as claimed in clause 21, characterized in that said polar monomer is a polar vinyl monomer.

27. The method as claimed in clause 21, characterized in that said polar monomer is selected from poly (ethylene glycol) acrylates, poly (ethylene glycol) alkyl ether acrylates, poly (ethylene glycol) methacrylates, poly (ethylene glycol) alkyl ether methacrylates, acrylic acid, maleic anhydride, itaconic acid, sodium acrylate, 3-hydroxypropyl methacrylate, 2-hydroxyethyl methacrylate, -hydroxypropyl acrylate, 2-hydroxyethyl acrylate, acrylamide, glycyl methacrylate, 2-cyanoethyl acrylate, glycyl acrylate, 4-nitrophenyl acrylate, pentabromophenyl acrylate, poly (propylene glycol) methacrylates, poly (propylene glycol) acrylates, 2-propene-1 Sulfonic acid and its sodium salt, 2-sulfoethyl acrylate, 2-sulfoethyl methacrylate, 3-sulfopropyl acrylate, 3-sulfopropyl methacrylate or mixtures thereof.

28. The method as claimed in clause 21, characterized in that said polar monomer is selected from 2-hydroxyethyl methacrylate, polyethylene glycol methacrylate or its analogues.

29. The method as claimed in clause 21, characterized in that said water soluble polymer is selected from polyethylene oxide, polyvinyl alcohol, hydroxypropyl cellulose or polyacrylic acid.

30. The method as claimed in clause 21, characterized in that said biodegradable polymer is selected from poly (β-hydroxybutyrate-co- -hydroxyvalerate), poly (ethylene succinate), poly (butylene succinate), polycaprolactone or mixtures thereof. these, said polar monomer is selected from 2-hydroxyethyl methacrylate, polyethylene glycol methacrylate or its analogs and said water-soluble polymer is selected from polyethylene oxide, polyvinyl alcohol, hydroxypropyl cellulose, polyacrylamide, sulfonated polyester or polyacrylic acid.

31. A method for making a biodegradable polymer mix composition responsive to water comprising a single step of combining a biodegradable polymer, a water soluble polymer, a polar vinyl monomer and a free radical initiator under sufficient heat, a cut high and high intensity dispersive mixing so high and high intensity dispersive mixing so that the biodegradable polymer and said water soluble polymer are grafted with said polar vinyl monomer and said biodegradable polymer and said water soluble polymer form a homogeneous mixture.

32. The water-sensitive polymer blends of a modified biodegradable polymer selected from poly (hydroxyalkanoate), polyalkylene succinates, polycaprolactones or mixtures thereof which are hydrolytically degradable and a modified water-soluble polymer.

33. Water-sensitive polymer mixtures of modified poly (modified ethylene oxide and poly (hydroxyalkanoate), poly (alkylene) succinates, polycaprolactones or mixtures thereof which are hydrolytically degradable. E S U M E N The present invention relates to a hydrolytically modified biodegradable polymer and to a method for making a hydrolytically modified biodegradable polymer. In a preferred embodiment, the invention relates to a method for grafting polar groups into biodegradable polymers and modified biodegradable polymer compositions produced by the method. The polymer compositions are useful as components in disposable articles with water discharge and which can be degraded. Also disclosed are mixtures of water-sensitive polymers and the method for making these polymer blends.