WO2021081660A1

WO2021081660A1 - Polymeric foams, methods, and articles thereof

Info

Publication number: WO2021081660A1
Application number: PCT/CA2020/051469
Authority: WO
Inventors: Maksim SHIVOKHIN; Sarah NEWBY; George J. Pehlert; Antonios Doufas; Jean-Mathieu Benoît Louis PIN; Patrick Chang Dong LEE
Original assignee: Exxonmobil Chemical Patents Inc.; The Governing Council Of University Of Toronto
Priority date: 2019-10-31
Filing date: 2020-10-30
Publication date: 2021-05-06

Abstract

Described are polymeric foams made from polypropylene random copolymers that have a high melt strength and a high stiffness, and that provide beneficial mechanical properties for expanded bead foam (EPP) applications. The polypropylene random copolymers, at least in part, help to address existing challenges of accessing new EPP applications requiring higher stiffness, while maintaining a relatively low melting temperature, and a melt flow rate (MFR) of about 6 to about 10, that is usually used for EPP applications.

Description

POLYMERIC! FOAMS. METHODS. AND ARTICLES THEREOF

FIELD

[0001] The present disclosure relates generally to materials that can be foamed, and articles formed thereof. More particularly, the present disclosure relates to polymeric foams, methods, and articles thereof.

BACKGROUND

[0002] Polypropylene is increasingly used as a base material in processes. Its use has recently become realized as a foamable polymer as well. Particularly, polypropylene random copolymers (e.g., resins) with high stiffness can be useful for the production of expanded bead foams (EPP). In general, expanded bead foams are made using polypropylene random copolymers having an ethylene content (C2%) of about 3 to 4 with a flex modulus of ~750MPa to 850MPa and melting temperature of about 148 °C. In order to expand use of polypropylene random copolymers to applications requiring higher stiffness, where instead injection molded parts are currently being used, converters require higher stiffness grade resins (e.g. having a flexural modulus >1200 MPa) while maintaining a resin melting temperature below about 154 °C (which is approximately related to the maximum allowed 5 Bar steam pressure in a steam chest where pre-expanded beads coming out of an autoclave are then molded into three-dimensional foam parts).

SUMMARY

[0003] In an aspect of the present disclosure, there is provided a polymeric foam comprising: (i) a density in a range of about 0.02 g/cc to about 1 g/cc; (ii) an open cell percentage in a range of about 1 to about 75; and (iii) a double crystal melting peak with a low melting peak in a temperature range of about 140°C to about 165°C and a high melting peak in a temperature range of about 150°C to about 175°C.

[0004] In an embodiment of the present disclosure, there is provided a polymeric foam further comprising a cell density in a range of about 10⁶ cells/cm³ to about 10⁹ cells/cm³. [0005] In another embodiment, there is provided a polymeric foam further comprising an expansion ratio in a range of about 1 to about 35. In another embodiment, the expansion ratio is in a range of about 1.1 to about 25, or about 1.1 to about 20, or about 1.1 to about

15, or about 1.1 to about 10, or about 1.1 to about 5. [0006] In another embodiment, there is provided a polymeric foam further comprising a melting enthalpy in a range of about 50 J/g to about 110 J/g. In another embodiment, the melting enthalpy is in a range of about 80 J/g to about 110 J/g.

[0007] In another embodiment, there is provided a polymeric foam further comprising a dynamic storage modulus in compression mode in a range of about 0.1 MPa to about 3MPa with a loss tangent in a range between 0.1 and 0.3 as measured at temperatures in a range of about 25°C to about 150°C.

[0008] In another embodiment, there is provided a polymeric foam wherein the density is in a range of about 0.03 g/cc to about 0.3 g/cc. In another embodiment, the density is in a range of about 0.8 g/cc to about 0.9 g/cc.

[0009] In another embodiment, there is provided a polymeric foam wherein the open cell percentage is in a range of about 1 to about 65, or about 1 to about 45. In another embodiment, the open cell percentage is in a range of about 1 to about 20, or about 1 to about 10.

[0010] In another embodiment, there is provided a polymeric foam wherein the double crystal melting peak has a low melting peak in a temperature range of about 145°C to about 155°C and a high melting peak in a temperature range of about 155°C to about 170°C. [0011] In another embodiment, there is provided a polymeric foam wherein the polymeric foam is comprised of a polypropylene random copolymer.

[0012] In another embodiment, there is provided a polymeric foam wherein the polymeric foam is further comprised of talc, a nanoclay, or a combination of a polymer with talc or a nanoclay. In another embodiment, the polymer is maleic anhydride grafted polypropylene.

[0013] In another embodiment, there is provided a polymeric foam wherein the polypropylene random copolymer has a flexural modulus > 1100 MPa. In another embodiment, the polypropylene random copolymer has a flexural modulus is in a range of about 1200 MPa to about 1400 MPa. In another embodiment, the flexural modulus is in a range of about 1200 MPa to about 1350 MPa.

[0014] In another embodiment, there is provided a polymeric foam wherein the polypropylene random copolymer has a melting point temperature, T_m, of <160°C. In another embodiment, the polypropylene random copolymer has a melting point temperature, Tm, in a range of about 152°C to about 156°C. [0015] In another embodiment, there is provided a polymeric foam wherein the polypropylene random copolymer has a crystallization temperature, Tc, of <115°C. In another embodiment, the crystallization temperature, T_c is in a range of about 100°C to about 111°C.

[0016] In another embodiment, there is provided a polymeric foam wherein the polypropylene random copolymer has a melt flow rate in a range of about 1 g/lOmin to about 10 g/lOmin (2.16kg at 230°C; ASTM-D1238). In another embodiment, the melt flow rate is in a range of about 4 g/lOmin to about 10 g/lOmin (2.16kg at 230°C; ASTM-D1238). In another embodiment, the melt flow rate is in a range of about 6 g/lOmin to about 10 g/lOmin (2.16kg at 230°C; ASTM-D1238).

[0017] In another embodiment, there is provided a polymeric foam wherein the polypropylene random copolymer has a melt strength in a range of about 5 cN to about 25 cN.

[0018] In another embodiment, there is provided a polymeric foam wherein the polypropylene random copolymer has a tensile strain at break in a range of about 415% to about 485%. In another embodiment, there is provided a polymeric foam wherein the polypropylene random copolymer has a tensile stress at break in a range of about 15 MPa to about 40 MPa. In another embodiment, there is provided a polymeric foam wherein the polypropylene random copolymer has a Young’s modulus in a range of about 1500 MPa to about 1900 MPa. In another embodiment, there is provided a polymeric foam wherein the polypropylene random copolymer has a tensile stress at yield in a range of about 30 MPa to about 40 MPa. In another embodiment, there is provided a polymeric foam wherein the polypropylene random copolymer has a tensile strain at yield in a range of about 0.07 mm/mm to about 0.15 mm/mm.

[0019] In another embodiment, there is provided a polymeric foam wherein the polypropylene random copolymer has a zero-shear viscosity in a range of about 3500 Pa.s to about 33000 Pa.s.

[0020] In another embodiment, there is provided a polymeric foam wherein the polypropylene random copolymer has a M_n in a range of about 55,000 g/mole to about

90,000 g/mole. In another embodiment, there is provided a polymeric foam wherein the polypropylene random copolymer has a M in a range of about 250,000 g/mole to about

500,000 g/mole. In another embodiment, there is provided a polymeric foam wherein the polypropylene random copolymer has a M /M_n in a range of about 3 to about 7. In another embodiment, there is provided a polymeric foam wherein the polypropylene random copolymer has a Mz in a range of about 800,000 g/mole to about 2,000,000 g/mole. In another embodiment, there is provided a polymeric foam wherein the polypropylene random copolymer has a M_z/M in a range of about 2 to about 5. In another embodiment, there is provided a polymeric foam wherein the polypropylene random copolymer has a M_z+i in a range of about 1,000,00 g/mole to about 5,000,000 g/mole.

[0021] In another embodiment, there is provided a polymeric foam wherein the polypropylene random copolymer has a dynamic storage compression modulus in a range of about 5 MPa to about 5 GPa and a loss tangent in a range between about 0.01 and 0.1 as measured at temperatures in a range of about -25 °C to about 150 °C.

[0022] In another embodiment, there is provided a polymeric foam wherein the polypropylene random copolymer is comprised of propylene and ethylene derived units. In another embodiment, the polypropylene random copolymer is comprised of <2 wt% of ethylene derived units.

[0023] In another aspect of the present disclosure, there is provided a method of forming the polymeric foam as described herein, the method comprising heating the polypropylene random copolymer; impregnating the polypropylene random copolymer with a foaming agent under a first pressure; and reducing the first pressure to a second pressure to form the polymeric foam.

[0024] In another embodiment of the present disclosure, there is provided a method wherein reducing the first pressure to the second pressure causes the foaming agent to form bubbles within the polypropylene random copolymer thereby forming the polymeric foam. [0025] In another embodiment, there is provided a method, wherein the foaming agent is a gaseous agent. In another embodiment, the gaseous agent is carbon dioxide, nitrogen, chlorofluorocarbons, hydrochlorofluorocarbons, propane, pentane, isobutene, air, or a combination thereof.

[0026] In another embodiment, there is provided a method wherein heating the polypropylene random copolymer comprises heating at a temperature in a range of about 130°C to about 150°C. In another embodiment, the temperature is in a range of about 135°C to about 145°C.

[0027] In another embodiment, there is provided a method wherein impregnating the polypropylene random copolymer with a foaming agent occurs over a saturation time in a range of about 5 min to about 120 min. In another embodiment, the saturation time is in a range of about 5 min to about 15 hours; or about 120 min to about 15 hours; or about 5 hours to about 15 hours; or about 10 hours to about 15 hours. In another embodiment, there is provided a method wherein, when impregnating the polypropylene random copolymer with a foaming agent, the first pressure is maintained at a constant pressure. In another embodiment, the first pressure is maintained at a pressure in a range of about 500 psi to about 5000 psi. In another embodiment, there is provided a method wherein reducing the first pressure to the second pressure comprises reducing the first pressure at a rate of about 0.1 MPa/s to about 400 MPa/s. In another embodiment, the first pressure is reduced at a rate of about 0.001 MPa/s to about 400 MPa/s; or about 0.001 MPa/s to about 100 MPa/s; or about 0.001 MPa/s to about 25 MPa/s; or about 0.001 MPa/s to about 5 MPa/s; or about 0.001 MPa/s to about 0.1 MPa/s. In another embodiment, there is provided a method the second pressure is approximately atmospheric pressure.

[0028] In another aspect of the present disclosure, there is provided an article comprising the polymeric foam as described herein. In another embodiment, the article is an automotive part. In another embodiment, the article is a storage container. In another embodiment, the article is sporting equipment.

[0029] In another aspect of the present disclosure, there is provided a foamed article, comprising a polymeric foam, the polymeric foam comprising:

(i) a polypropylene random copolymer having a flex modulus > 1100 MPa and a melting point temperature, T_m, of <160°C;

(ii) a density in a range of about 0.02 g/cc to about 1 g/cc;

(iii) an open cell percentage in a range of about 1 to about 75; and

(iv) a double crystal melting peak with a low melting peak in a temperature range of about 140°C to about 165°C and a high melting peak in a temperature range of about 150°C to about 175°C.

[0030] In another embodiment, there is provided a foamed article wherein the polymeric foam further comprises a cell density in a range of about 10⁶ cells/cm³ to about 10⁹ cells/cm³. [0031] In another embodiment, there is provided a foamed article wherein the polymeric foam further comprises an expansion ratio of in a range of about 1 to about 35, or about 1.1 to about 20, or about 1.1 to about 15, or about 1.1 to about 10, or about 1.1 to about 5. [0032] In another embodiment, there is provided a foamed article wherein the polymeric foam further comprises a melting enthalpy in a range of about 50 J/g to about 110 J/g, or about 80 J/g to about 110 J/g. [0033] In another embodiment, there is provided a foamed article wherein the polymeric foam further comprises a dynamic storage compression modulus in a range of about 0.1 to about 3 MPa and loss tangent in a range between 0.1 and 0.3.

[0034] In another embodiment, there is provided a foamed article wherein the density is in a range of about 0.03 g/cc to about 0.3 g/cc. In another embodiment, the density is in a range of about 0.3 g/cc to about 0.9 g/cc, or about 0.8 g/cc to about 0.9 g/cc.

[0035] In another embodiment, there is provided a foamed article wherein the open cell percentage is in a range of about 1 to about 65, or about 1 to about 45, or about 1 to about 20, or about 1 to about 10.

[0036] In another embodiment, there is provided a foamed article wherein the flexural modulus is about 1200 MPa to about 1400 MPa, or about 1200 MPa to about 1350 MPa. [0037] In another embodiment, there is provided a foamed article wherein the polypropylene random copolymer has a crystallization temperature, Tc, of <115°C. In another embodiment, the polypropylene random copolymer has a crystallization temperature, Tc, is in a range of about 100°C to about 111°C.

[0038] In another embodiment, there is provided a foamed article wherein the T_m is in a range of about 152°C to about 156°C.

[0039] In another embodiment, there is provided a foamed article wherein the polypropylene random copolymer has a melt flow rate in a range of about 1 g/lOmin to about 10 g/lOmin, or about 4 g/lOmin to about 10 g/lOmin, or about 6 g/lOmin to about 10 g/lOmin (2.16kg at 230°C; ASTM-D1238).

[0040] In another embodiment, there is provided a foamed article wherein the polypropylene random copolymer has a melt strength in a range of about 5 cN to about 25 cN.

[0041] In another embodiment, there is provided a foamed article wherein the polypropylene random copolymer has a tensile strain at break in a range of about 415% to about 485%. In another embodiment, there is provided a foamed article wherein the polypropylene random copolymer has a tensile stress at break in a range of about 15 MPa to about 40 MPa. In another embodiment, there is provided a foamed article wherein the polypropylene random copolymer has a Young’s modulus in a range of about 1500 MPa to about 1900 MPa. In another embodiment, there is provided a foamed article wherein the polypropylene random copolymer has a tensile stress at yield in a range of about 30 MPa to about 40 MPa. In another embodiment, there is provided a foamed article wherein the polypropylene random copolymer has a tensile strain at yield in a range of about 0.07 mm/mm to about 0.15 mm/mm.

[0042] In another embodiment, there is provided a foamed article wherein the polypropylene random copolymer has a zero-shear viscosity in a range of about 3500 Pa.s to about 33000 Pa.s.

[0043] In another embodiment, there is provided a foamed article wherein the polypropylene random copolymer has a M_n in a range of about 55,000 g/mole to about 90,000 g/mole. In another embodiment, there is provided a foamed article wherein the polypropylene random copolymer has a M in a range of about 250,000 g/mol. to about 500,000 g/mol. In another embodiment, there is provided a foamed article wherein the polypropylene random copolymer has a M /M_n in a range of about 3 to about 7. In another embodiment, there is provided a foamed article wherein the polypropylene random copolymer has a M_z in a range of about 800,000 g/mol. to about 2,000,000 g/mol. In another embodiment, there is provided a foamed article wherein the polypropylene random copolymer has a M_z/M in a range of about 2 to about 5. In another embodiment, there is provided a foamed article wherein the polypropylene random copolymer has a M_z+i in a range of about 1,000,000 g/mol to about 5,000,000 g/mol.

[0044] In another embodiment, there is provided a foamed article wherein the polypropylene random copolymer has a dynamic storage compression modulus in a range of about 5 MPa to about 5 GPa and loss tangent in a range between about 0.01 and 0.1 as measured at temperatures in a range of about -25 °C to about 150 °C.

[0045] In another embodiment, there is provided a foamed article wherein the polypropylene random copolymer is comprised of propylene and ethylene derived units. In another embodiment, the polypropylene random copolymer is comprised of <2 wt% of ethylene derived units.

[0046] In another embodiment, there is provided a foamed article wherein the polymeric foam further comprises talc, a nanoclay, or a combination of a polymer with talc or a nanoclay. In another embodiment, the polymer is maleic anhydride grafted polypropylene.

BRIEF DESCRIPTION OF THE FIGURES

[0047] Embodiments of the present disclosure will now be described, by way of example only, with reference to the attached Figures. [0048] FIG. 1 graphically depicts small angle oscillatory shear data of polypropylene random copolymer (PRC) PRC-Sample 2.

[0049] FIG. 2 graphically depicts dynamic compression modulus data collected at 140 °C for a foamed sample comprising polypropylene random copolymer (PRC) PRC-Sample 1.

[0050] FIG. 3 graphically depicts dynamic compression modulus data collected at 145 °C for a foamed sample comprising polypropylene random copolymer (PRC) PRC-Sample 1.

[0051] FIG. 4 graphically depicts dynamic compression modulus data collected at 145 °C for a foamed sample comprising polypropylene random copolymer (PRC) PRC-Sample 2.

[0052] FIG. 5 depicts differential scanning calorimetry data of polypropylene random copolymer (PRC) PRC-Sample 3.

[0053] FIG. 6 depicts differential scanning calorimetry data of polypropylene random copolymer (PRC) PRC-Sample 4.

[0054] FIG. 7 depicts differential scanning calorimetry data of polypropylene random copolymer (PRC) PRC-Sample 1.

[0055] FIG. 8 depicts differential scanning calorimetry data of polypropylene random copolymer (PRC) PRC-Sample 2.

[0056] FIG. 9 depicts dynamic temperature ramp data of unfoamed resins: SI- PRC- Sample 3; S2-PRC-Sample 4; S3-PRC-Sample 1; S4-PRC-Sample 2 .

DETAILED DESCRIPTION

[0057] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0058] As used in the specification and claims, the singular forms “a”, “an” and “the” include plural references unless the context clearly dictates otherwise.

[0059] The term “comprising” as used herein will be understood to mean that the list following is non-exhaustive and may or may not include any other additional suitable items, for example one or more further feature(s), component(s) and/or ingredient(s) as appropriate. [0060] As used herein, “consisting essentially of’ means that the claimed polymeric foam, article, or polymer includes only the named components and no additional components that will alter its measured properties by any more than 20, or 15, or 10%, and most preferably means that additional components are present to a level of less than 5, or 4, or 3, or 2 wt% by weight of the composition. Such additional components can include, for example, fdlers, nucleators, colorants, antioxidants, alkyl-radical scavengers (preferably vitamin E, or other tocopherols and/or tocotrienols), anti-UV agents, acid scavengers, curatives and cross-linking agents, aliphatic and/or cyclic containing oligomers or polymers (often referred to as hydrocarbon resins), and other additives well known in the art. As it relates to a process, the phrase “consisting essentially of’ means that there are no other process features that will alter the claimed properties of the polymer, polymer blend or article produced therefrom by any more than 10, 15 or 20%.

[0061] For all jurisdictions in which the doctrine of “incorporation by reference” applies, all of the test methods, patent publications, patents and reference articles are hereby incorporated by reference either in their entirety or for the relevant portion for which they are referenced.

[0062] In an aspect, the present disclosure provides a polymeric foam comprising a density in a range of about 0.02 g/cc to about 1 g/cc; an open cell percentage in a range of about 1 to about 75; and a double crystal melting peak with a low melting peak in a temperature range of about 140°C to about 165°C and a high melting peak in a temperature range of about 150°C to about 175°C.

[0063] In another aspect, the present disclosure provides a method of forming the polymeric foam as described herein, the method comprising heating a polypropylene random copolymer; impregnating the polypropylene random copolymer with a foaming agent under a first pressure; and reducing the first pressure to a second pressure to form the polymeric foam.

[0064] In another aspect, the present disclosure provides an article comprising the polymeric foam.

[0065] In another aspect, the present disclosure provides a foamed article, comprising a polymeric foam, the polymeric foam comprising: a polypropylene random copolymer having a flex modulus > 1100 MPa and a melting point temperature, T_m, of <160°C; a density in a range of about 0.02 g/cc to about 1 g/cc; an open cell percentage in a range of about 1 to about 75; and a double crystal melting peak with a low melting peak in a temperature range of about 140°C to about 165°C and a high melting peak in a temperature range of about 150°C to about 175°C.

[0066] Described herein are polymeric foams comprising (consisting essentially of, or consisting of) polypropylene random copolymers, the polypropylene random copolymers having a high melt strength and a high stiffness, that provide beneficial mechanical properties for expanded bead foam (EPP) applications. Said polypropylene random copolymers, at least in part, help to address existing challenges of accessing new EPP applications requiring higher stiffness, while maintaining a relatively low melting temperature of 152-156°C and a melt flow rate (MFR) range of about 6 to about 10 that is usually used for EPP applications. It is described herein that said polypropylene random copolymers can be foamed to obtain a polymeric foam with bulk density as low as about 0.03 g/cc and a dynamic storage modulus in compression mode as high as about 3 MPa with a loss tangent as high as 0.3 if foamed, for example, in a batch at temperatures between about 135 °C to about 145 °C, under CO2 pressures between about 1000 psi to about 2000 psi, and saturation times of about 30 to about 60 minutes.

[0067] More particularly, herein described is a polymeric foam, or article comprising the polymeric foam, or a foamed article that comprises high melt strength polypropylene random copolymers with a C2 content (ethylene derived units) of about <2%, or <E5wt% with a MFR range between about 1 to about 10, having a melting temperature of <160 °C. Said polypropylene random copolymers were found to have a high stiffness (flexural modulus secant 1%) of about 1200 MPa to about 1350 MPa (e.g., about 1285 MPa, or about 1345), with a melt strength of about 5 cN to about 22 cN. The polymeric foams made out of these polypropylene random copolymers (i.e., resins) were found to generate a double crystal melting peak (DCMP). It was considered that the temperature range between Tm-high and Tm-low in the DCMP could be recognized as a processing steam temperature window, as the DCMP value was found to reach up to about 17°C, or up to about 20°C depending on saturation time and CO2 pressure.

[0068] Thus, disclosed in any embodiment, is a polymeric foam comprising (or consisting essentially of, or consisting of) a density in a range of about 0.02 g/cc to about 1 g/cc; an open cell percentage in a range of about 1 to about 75; and a double crystal melting peak with a low melting peak in a temperature range of about 140°C to about 165°C and a high melting peak in a temperature range of about 150°C to about 175°C. [0069] In any embodiment, the polymeric foam has a density in a range of about 0.02 g/cc to about 0.9 g/cc; or about 0.02 g/cc to about 0.5 g/cc; or about 0.01 g/cc to about 0.3 g/cc; or about 0.8 g/cc to about 0.9 g/cc. In another embodiment, the polymeric foam has an open cell percentage in a range of about 1 to about 65; or about 1 to about 45; or about 1 to about 30; or about 1 to about 20; or about 1 to about 10. In any embodiment, the polymeric foam has a double crystal melting peak with a low melting peak in a temperature range of about 140°C to about 165°C; or about 145°C to about 155°C. In any embodiment, the polymeric foam has a double crystal melting peak with a high melting peak in a temperature range of about 150°C to about 175°C; or about 155°C to about 170°C.

[0070] In any embodiment, the polymeric foam further comprises (or consists essentially of, or consists of) a cell density in a range of about 10⁶ cells/cm³ to about 10⁹ cells/cm³; or about 10⁷ cells/cm³ to about 10⁹ cells/cm³; or about 10⁸ cells/cm³ to about 10⁹ cells/cm³. In any embodiment, the polymeric foam further comprises (or consists essentially of, or consists of) an expansion ratio in a range of about 1 to about 35; or about 1.1 to about 25, or about 1.1 to about 20, or about 1.1 to about 15, or about 1.1 to about 10, or about 1.1 to about 5. In any embodiment, the polymeric foam further comprises (or consists essentially of, or consists of) a melting enthalpy in a range of about 50 J/g to about 110 J/g; or about 70 J/g to about 110 J/g; or about 80 J/g to about 110 J/g; or about 100 J/g to about 110 J/g. In any embodiment, the polymeric foam further comprises (or consists essentially of, or consists of) a dynamic compression modulus in a range of about 0.1 to about 3 MPa with a loss tangent as high as 0.3 if measured at between room temperature and about 150°C. [0071] In any embodiment, the polymeric foam further comprises (or consists essentially of, or consists of) a polypropylene random copolymer. In any embodiment, the polypropylene random copolymer is comprised of (or consists essentially of, or consists of) propylene and ethylene derived units. In any embodiment, the polypropylene random copolymer is comprised (or consists essentially of, or consists of) <2 wt% of ethylene derived units; or <1.5 wt%; or, the ethylene derived units are in a range of about 1.2 wt% to about 1.7 wt%; or about 1.3 wt% to about 1.6 wt%.

[0072] In any embodiment, the polypropylene random copolymer has a flexural modulus > 1100 MPa; or in a range of about 1200 MPa to about 1400 MPa; or about 1200

MPa to about 1350 MPa; about 1200 MPa to about 1345 MPa; or about 1200 MPa to about

1300 MPa. In any embodiment, the polypropylene random copolymer has a melting point temperature, T_m, of <160°C; or in a range of about 152°C to about 156°C. In any embodiment, the polypropylene random copolymer has a crystallization temperature, Tc. of

<115°C; or in a range of about 100°C to about 111°C; or about 105°C to about 111°C. In any embodiment, the polypropylene random copolymer has a melt flow rate in a range of about 1 g/lOmin to about 12 g/lOmin; or about 1 g/lOmin to about 10 g/lOmin; or about

1 g/lOmin to about 5 g/lOmin; or about 5 g/lOmin to about 10 g/lOmin; or about 6 g/lOmin to about 10 g/lOmin (2.16kg at 230°C; ASTM-D1238). In any embodiment, the polypropylene random copolymer has a melt strength in a range of about 5 cN to about 30 cN; or in a range of about 5 cN to about 25 cN; in a range of about 5 cN to about 20 cN; in a range of about 5 cN to about 15 cN; in a range of about 5 cN to about 10 cN.

[0073] In any embodiment, the polypropylene random copolymer has a tensile strain at break in a range of about 415% to about 485%; or about 425% to about 485%; about 435% to about 485%; about 445% to about 485%; about 455% to about 485%; about 465% to about 485%; about 475% to about 485%. In any embodiment, the polypropylene random copolymer has a tensile stress at break in a range of about 15 MPa to about 40 MPa; about

15 MPa to about 35 MPa; or about 20 MPa to about 40 MPa; about 30 MPa to about 40

MPa. In any embodiment, the polypropylene random copolymer has a Young’s modulus in a range of about 1500 MPa to about 1900 MPa; or about 1600 MPa to about 1900 MPa; or about 1700 MPa to about 1900 MPa; or about 1800 MPa to about 1900 MPa. In any embodiment, the polypropylene random copolymer has a tensile stress at yield in a range of about 30 MPa to about 40 MPa; or about 30 MPa to about 35 MPa; or about 35 MPa to about 40 MPa. In any embodiment, the polypropylene random copolymer has a tensile strain at yield in a range of about 0.07 mm/mm to about 0.15 mm/mm; or about 0.08 mm/mm to about 0.15 mm/mm; or about 0.09 mm/mm to about 0.15 mm/mm; or about 0.11 mm/mm to about 0.15 mm/mm; or about 0.12 mm/mm to about 0.15 mm/mm. In any embodiment, the polypropylene random copolymer has a zero-shear viscosity in a range of about 3500

Pa.s to about 32000 Pa.s; or about 3600 Pa.s to about 32000 Pa.s; or about 3600 Pa.s to about 22000 Pa.s; about 3600 Pa.s to about 12000 Pa.s; about 3600 Pa.s to about 8000 Pa.s; about 3600 Pa.s to about 6000 Pa.s; about 3600 Pa.s to about 5000 Pa.s.

[0074] In any embodiment, the polypropylene random copolymer of the polymeric foam has a melt strength in a range of about 5 cN to about 30 cN; or in a range of about 5 cN to about 25 cN; in a range of about 5 cN to about 22 cN; in a range of about 5 cN to about 15 cN; in a range of about 5 cN to about 10 cN; or, has a melt strength (190°C) of at least 5, or

10, or 20, or 30 cN. The melt strength is determined using a capillary rheometer such as a Rheo-tester™ 1000 capillary rheometer in conjunction with a wheel-driven extensional rheometer such as a Rheotens™ 71.97, where the capillary rheometer is set at a temperature of 190°C, the die a 30/2 (mm) ratio die, the piston speed at 0.32 mm/s, where the piston diameter is 15 mm, and the shear rate at 72 sec ¹, and where the strand (vertical) had a length of 105 mm, set at a velocity of 18 mm/s. Velocity of the rotating rollers was increased at a constant acceleration of 12 mm/s² until the polymer melt broke. Force at which the polymer melt broke was the “melt strength”.

[0075] In any embodiment, the polypropylene random copolymer of the polymeric foam has a number average molecular weight (Mn) of at least 40,000, or 50,000 g/mole, or 60,000 g/mole, or 70,000 g/mole, or 80,000 g/mole, or within a range from 40,000, or 50,000 g/mole to 60,000, or 70,000, or 80,000 g/mole. In any embodiment, the polypropylene random copolymer a weight average molecular weight (Mw) of at least 200,000 g/mole, or 300,000 g/mole, or 400,000 g/mole, or 500,000 g/mole, or 600,000 g/mole, or within a range from 200,000, or 300,000 g/mole to 400,000, or 500,000, or 600,000 g/mole. In any embodiment, the polypropylene random copolymer has a molecular weight distribution (Mw/Mn) of at least 3, or 4, or 5, or 6, or 7; or within a range from 3, or 4, to 5, or 6 or 7. These molecular weight features are determined using gel permeation chromatography as described below (e.g., see Example 1).

[0076] In any embodiment, the polypropylene has a z-average molecular weight (Mz) of at least 700,000, or 800,000, or, 1,000,000, or 1,500,000, or 2,000,000 g/mole, or within a range from 700,000, or 800,000, or 900,000 g/mole to 1,000,000, or 1,500,000, or 2,000,000 g/mole. Further, in any embodiment the Mz/Mn is at least 2, or 3, or 4, or 5. Also, in any embodiment the polypropylene has an Mz+1 value of at least 1,000,000, or 2,000,000, or 3,000,000, or 4,000,000, or 5,000,000 g/mole; or within a range from 1,000,000, or 2,000,000 g/mole to 3,000,000, or 4,000,000, or 5,000,000 g/mole.

[0077] The polypropylene random copolymer of the polymeric foam as described herein maintains a certain desirable level of crystallinity as indicated by its thermal properties. In any embodiment, the polypropylene random copolymer has a melting point temperature, Tm, of <160°C; or in a range of about 152°C to about 156°C. In any embodiment, the polypropylene random copolymer has a crystallization temperature, T_c, of <115°C; or in a range of about 100°C to about 111°C; or about 105°C to about 111°C. These thermal properties are determined as described below using differential scanning calorimetry (DSC) (e.g. see Example 1, FIG. 5 to 8). [0078] The polypropylene random copolymer of the polymeric foam as described herein have certain desirable properties, such as high stiffness as indicated in the flexural modulus value. In any embodiment, the polypropylene random copolymer has a flexural modulus (1% secant) > 1100 MPa; or in a range of about 1200 MPa to about 1400 MPa; or about 1200 MPa to about 1350 MPa; about 1200 MPa to about 1345 MPa; or about 1200 MPa to about 1300 MPa.

[0079] In some embodiments, the polypropylene random copolymer of the polymeric foam as described herein is “reactor grade”, meaning polymers not having undergone any post-reactor process to change its chemical structure, such as by reactive extrusion, electron- beam or ultra-violet radiation, or silane grafting. A polypropylene random copolymer is “reactor grade” if no byproducts of peroxide reactions (visbreaking or cross-linking/long chain branch inducing) can be detected, and no grafted moieties are detected, and no long chain branching and/or cross-linked chains are detected. Byproducts of peroxide reactions include alcohols and ketones and can be detected by NMR. Long chain branching can be determined using the intrinsic viscosity (g’vis) of a polymer, which should have a value of less than 1.0, for a branched and/or cross-linked polypropylene.

[0080] In any embodiment, the polypropylene random copolymer of the polymeric foam as described herein, cross-linked or not, can comprise any combination of second or third polymer(s) such as polyethylene, polypropylene, ethylene-propylene copolymers, butyl rubber, polyisoprene, polybutadiene, polystyrene, styrene butadiene, polyamides, polyesters, polyurethanes, polyacrylates, and combinations thereof. In any embodiment, the polypropylene random copolymer comprises within a range from 5, or 10 to 20, or 30, or 40, or 50 wt% of the second polymer as a blend. The polypropylene random copolymer may also be associated with one or more of the second polymers in an article as co-components of the article, such as layers or parts of the article.

[0081] In particular, up to about 20 wt% of a low molecular weight polyolefin, by weight of the blend of polyolefin and polypropylene, may be added to the polypropylene random copolymer by melt extrusion or any other blending means. The “low molecular weight polyolefin” is a polyolefin polymer having a weight average molecular weight of no more than 80,000, or 100,000 g/mole, preferably comprising ethylene and C4 to CIO derived units, most preferably comprising propylene and optionally ethylene derived units. In any embodiment, the low molecular weight polyolefin has a melt flow rate (230°C/2.16 kg) of at least 50, or 100, or 200, or 500 g/10 min, or within a range from 50, or 100, or 200, or 500 g/10 min to 1,500, or 2,000, or 5,000 g/10 min. In any embodiment, the low molecular weight polyolefin is selected from the group consisting of polypropylene homopolymers, polypropylene copolymers, polyethylene homopolymers, polyethylene copolymers, and blends thereof. Most preferably, the low molecular weight polyolefin is a polypropylene homopolymer, meaning that it comprises less than 1, or 2 wt% ethylene or C4 to CIO derived units. In any embodiment, the low molecular weight polyolefin has an Mw/Mn of less than 5, or 4, or 3.

[0082] The polypropylene random copolymer of the polymer foam described herein may be subject to any number of post-reactor processing steps, such as reactive extrusion processes described in WO 2016/126429 Al. Thus in any embodiment the polypropylene random copolymer is combined with an organic peroxide, especially a short half-life peroxide in a melt extrusion process to produce a branched polypropylene, such polypropylenes typically having an enhanced melt strength and extensional viscosity.

Preferably, this takes place in the absence of any additional monomers or cross-linking agents such as butadiene, 1,9-decadiene, norbomenes, or other diene-type monomers known in the art. Useful organic peroxides include those that are short half-life peroxides such as di-sec-butyl peroxydicarbonate, diisopropyl peroxydicarbonate, dicyclohexyl peroxydicarbonate, di(4-tert-butylcyclohexyl) peroxydicarbonate, dicetyl peroxydicarbonate, dibutyl peroxydicarbonate, di(2-ethylhexyl) peroxydicarbonate, didodecyl peroxydicarbonate, diicosyl peroxydicarbonate, and ditetracosyl peroxydicarbonate. Also, the polypropylene random copolymer may be treated with a long half-life peroxide such as 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 2,5-bis(tert- butylperoxy)-2,5-dimethylhexane, di-tert-butyl peroxide, and dicumyl peroxide to effect

“visbreaking” of the polypropylene random copolymer as is known in the art.

[0083] Any desirable method of forming the polypropylene random copolymer, as is known in the art, can be used to make the polypropylene random copolymer of the polymeric foam as described herein. In any embodiment, the polypropylene random copolymer, is made by combining propylene and co-monomer ethylene in the presence of a Ziegler-Natta catalyst having an external electron donor catalyst system. In any embodiment, said system has at least two external electron donors, wherein the concentration of the electron donors is within a range from 1 to 100 ppm. In any embodiment, the external electron donor catalyst system has at least two external electron donors, the external electron donors being organosilanes. The co-monomer level and level of external electron donors can be changed individually or together, sequentially or at the same time during the polymerization process. In any embodiment, the external electron donors are combined with the catalyst simultaneously, such as together in the same reaction zone or reactor.

[0084] In any embodiment, the polypropylene random copolymer of the polymeric foam as described herein is formed in the absence of dienes and/or vinyl compounds such as vinyl cycloalkanes, in particular vinyl cyclohexane, vinyl cyclopentane, vinyl-2-methyl cyclohexane and vinyl norbomane, 3-methyl-l -butene, styrene, p-methyl-styrene, 3-ethyl- 1 -hexene, butadiene, 1,9-decadiene, or mixtures thereof. Stated another way, in any embodiment the polypropylene random copolymer consists of monomer units derived from propylene and ethylene.

[0085] Ziegler-Natta catalysts suitable to produce the polypropylene random copolymer of the polymeric foam as described herein include solid titanium supported catalyst systems described in US 4,990,479; US 5,159,021; US 9,453,093; and WO 00/63261, and others. Briefly, the Ziegler-Natta catalyst can be obtained by: suspending a dialkoxy magnesium compound in an aromatic hydrocarbon that is liquid at 20 to 25°C; contacting the dialkoxy magnesium hydrocarbon composition with a titanium halide and with a diester of an aromatic dicarboxylic acid; and contacting the resulting functionalized dialkoxy magnesium-hydrocarbon composition of step with additional titanium halide.

[0086] The “catalyst system” typically includes a solid titanium catalyst component comprising titanium as well as magnesium, halogen, at least one non-aromatic “internal” electron donor, and at least one, preferably two or more “external” electron donors. The solid titanium catalyst component, also referred to as a Ziegler-Natta catalyst, can be prepared by contacting a magnesium compound, a titanium compound, and at least the internal electron donor. Examples of the titanium compound used in the preparation of the solid titanium catalyst component include tetravalent titanium compounds having the formula (1):

Ti(ORn)X₄-n, (1) wherein R is a hydrocarbyl radical, X is a halogen atom, and n is from 0 to 4.

[0087] The terms “hydrocarbyl radical,” “hydrocarbyl” and “hydrocarbyl group” are used herein interchangeably unless otherwise specified. For purposes of the present disclosure, a hydrocarbyl radical is defined to be Ci to C20 radicals, or Ci to C10 radicals, or C7, to C20 radicals, or C7 to C20 radicals that may be linear, branched, or cyclic where appropriate (aromatic or non-aromatic); and includes hydrocarbyl radicals substituted with other hydrocarbyl radicals and/or one or more functional groups comprising elements from Groups 13 - 17 of the periodic table of the elements. In addition, two or more such hydrocarbyl radicals may together form a fused ring system, including partially or fully hydrogenated fused ring systems, which may include heterocyclic radicals.

[0088] In some embodiments, the halogen-containing titanium compound is a titanium tetrahalide, or titanium tetrachloride. The titanium compounds may be used singly or in combination with each other. The titanium compound may be diluted with a hydrocarbon compound or a halogenated hydrocarbon compound. Non-limiting examples include titanium tetra-halides such as TiCri. TiBr4, and/or Tib: alkoxy titanium trihalides including Ti(OCH₃)Cl3, Ti(OC₂H₅)Cl3, Ti(0-n-C₄H₉)Cl3, Ti(OC₂H₅)Br3, and/or Ti(0-iso-C₄H₉)Br3; dialkoxytitanium dihalides including Ti(OCH3)₂Cl₂, Ti(OC₂Hs)₂Cl₂, Ti(0-n-C₄H₉)₂Cl₂ and/or T^OCffls^Bn; trialkoxytitanium monohalides including Ti(OCH3)3Cl, Ti(OC₂H5)3Cl, Ti(0-n-C₄H₉)3Cl and/or Ti(OC₂Hs)3Br; and/or tetraalkoxy titaniums including Ti(OCH3)₄, Ti(OC₂H5)₄. and/or Ti(0-n-C₄H₉)₄.

[0089] In some embodiments, the magnesium compound to be used in the preparation of the solid titanium catalyst component includes a magnesium compound having reducibility and/or a magnesium compound having no reducibility. Suitable magnesium compounds having reducibility may, for example, be magnesium compounds having a magnesium-carbon bond or a magnesium-hydrogen bond. Suitable examples of such reducible magnesium compounds include dimethyl magnesium, diethyl-magnesium, dipropyl magnesium, dibutyl magnesium, diamyl magnesium, dihexyl magnesium, didecyl magnesium, magnesium ethyl chloride, magnesium propyl chloride, magnesium butyl chloride, magnesium hexyl chloride, magnesium amyl chloride, butyl ethoxy magnesium, ethyl butyl magnesium, and/or butyl magnesium halides. These magnesium compounds may be used singly or they may form complexes with the organoaluminum co-catalyst as described herein. These magnesium compounds may be a liquid or a solid.

[0090] Suitable examples of the magnesium compounds having no reducibility include magnesium halides such as magnesium chloride, magnesium bromide, magnesium iodide, and magnesium fluoride; alkoxy magnesium halides, such as magnesium methoxy chloride, magnesium ethoxy chloride, magnesium isopropoxy chloride, magnesium phenoxy chloride, and magnesium methylphenoxy chloride; alkoxy magnesiums, such as ethoxy magnesium, isopropoxy magnesium, butoxy magnesium, n-octoxy magnesium, and 2-ethylhexoxy magnesium; aryloxy magnesiums such as phenoxy magnesium and dimethylphenoxy magnesium; and/or magnesium carboxylates, such as magnesium laurate and magnesium stearate.

[0091] Non-reducible magnesium compounds may be compounds derived from the magnesium compounds having reducibility, or may be compounds derived at the time of preparing the catalyst component. The magnesium compounds having no reducibility may be derived from the compounds having reducibility by, for example, contacting the magnesium compounds having reducibility with polysiloxane compounds, halogen-containing silane compounds, halogen-containing aluminum compounds, esters, alcohols, and the like.

[0092] The magnesium compounds having reducibility and/or the magnesium compounds having no reducibility may be complexes of the above magnesium compounds with other metals, or mixtures thereof with other metal compounds. They may also be mixtures of two or more types of the above compounds. Further, halogen-containing magnesium compounds, including magnesium chloride, alkoxy magnesium chlorides and aryloxy magnesium chlorides may be used.

[0093] Supported Ziegler-Natta catalysts may be used in combination with a co-catalyst, also referred to herein as a Ziegler-Natta co-catalyst. Compounds containing at least one aluminum-carbon bond in the molecule may be utilized as the co-catalysts, also referred to herein as an organoaluminum co-catalyst. Suitable organoaluminum compounds include organoaluminum compounds of the general formula (2):

R^!mAKOR^nHpXq, (2) wherein R¹ and R² are identical or different, and each represents a hydrocarbyl radical containing from 1 to 15 carbon atoms, or 1 to 4 carbon atoms; X represents a halogen atom; and mis 1, 2, or 3; n is 0, 1, or 2; pis 0, 1, 2, or 3; and q is 0, 1, or 2; and wherein m+n+p+q=3. [0094] Other suitable organoaluminum compounds include complex alkylated compounds of metals of Group I of the Period Table (lithium, etc.) and aluminum represented by the general formula (3):

IVFAIR^, (3) wherein M¹ is the Group I metal such as Li, Na, or K, and R¹ is as defined in formula (2). [0095] Suitable examples of the organoaluminum compounds include trialkyl aluminums such as trimethyl aluminum, triethyl aluminum and tributyl aluminum; trialkenyl aluminums such as triisoprenyl aluminum; dialkyl aluminum alkoxides such as diethyl-aluminum ethoxide and dibutyl aluminum ethoxide; alkyl aluminum sesquialkoxides such as ethyl aluminum sesquiethoxide and butyl aluminum sesqui-butoxide; partially alkoxylated alkyl aluminums having an average composition represented by the general formula R¹2.5A1(OR²)O.5; partially halogenated alkyl aluminums, for example, alkyl aluminum dihalides such as ethyl aluminum dichloride, propyl aluminum dichloride and butyl aluminum dibromide; partially hydrogenated alkyl aluminums, for example, alkyl aluminum dihydrides such as ethyl aluminum dihydride and propyl aluminum dihydride; and partially alkoxylated and halogenated alkyl aluminums such as ethyl aluminum ethoxychloride, butyl aluminum butoxychloride, and ethyl aluminum ethoxybromide.

[0096] Electron donors are present with the metal components described herein in forming the catalyst suitable for producing the polypropylene random copolymer of the polymeric foam as described herein. Both “internal” and “external” electron donors are desirable for forming the catalyst suitable for making the polypropylene random copolymer. More particularly, the internal electron donor may be used in the formation reaction of the catalyst as the transition metal halide is reacted with the metal hydride or metal alkyl. Examples of suitable internal electron donors include amines, amides, ethers, esters, ketones, nitriles, phosphines, stilbenes, arsines, phosphoramides, thioethers, thioesters, aldehydes, alcoholates, and salts of organic acids.

[0097] In some embodiments, the one or more internal donors are non-aromatic. The non-aromatic internal electron donor may comprise an aliphatic amine, amide, ester, ether, ketone, nitrile, phosphine, phosphoramide, thioethers, thioester, aldehyde, alcoholate, carboxylic acid, or a combination thereof.

[0098] In other embodiments, the non-aromatic internal electron donor(s) comprises a Ci to C20 di ester of a substituted or unsubstituted C2 to C10 dicarboxylic acid. The non-aromatic internal electron donor(s) may be one or more succinate compounds according to formula (4):

wherein R¹ and R² are independently Ci to C20 linear or branched alkyl, alkenyl, or cycloalkyl hydrocarbyl radicals; and R³ to R⁶ are independently, hydrogen, halogen, or Ci to C20 linear or branched alkyl, alkenyl, or cycloalkyl hydrocarbyl radicals, wherein the R³ to R⁶ radicals are not joined together, wherein at least two of the R³ to R⁶ radicals are joined to form a cyclic divalent radical, or a combination thereof. The R³ to R⁵ groups of formula (4) may be hydrogen and R⁶ may be a radical selected from the group consisting of a primary branched, secondary or tertiary alkyl, or cycloalkyl radical having from 3 to 20 carbon atoms.

[0099] The internal donor may be a monosubstituted non-aromatic succinate compound.

Suitable examples include diethyl-secbutylsuccinate, diethylhexylsuccinate, diethyl- cyclopropylsuccinate, diethyl-trimethylsilylsuccinate, diethyl-methoxysuccinate, diethyl- cyclohexylsuccinate, diethyl-(cyclohexylmethyl) succinate, diethyl-t-butylsuccinate, diethyl-isobutylsuccinate, diethyl-isopropylsuccinate, diethyl-neopentylsuccinate, diethyl- isopentylsuccinate, diethyl-(l,l,l-trifluoro-2-propyl) succinate, diisobutyl-sec- butylsuccinate, diisobutylhexylsuccinate, diisobutyl-cyclopropylsuccinate, diisobutyl- trimethylsilylsuccinate, diisobutyl-methoxysuccinate, diisobutyl-cyclohexylsuccinate, diisobutyl-(cyclohexylmethyl) succinate, diisobutyl-t-butylsuccinate, diisobutyl- isobutylsuccinate, diisobutyl-isopropylsuccinate, diisobutyl-neopentylsuccinate, diisobutyl- isopentylsuccinate, diisobutyl-(l,l,l-trifluoro-2 -propyl) succinate, dineopentyl-sec- butylsuccinate, dineopentyl hexylsuccinate, dineopentyl cyclopropylsuccinate, dineopentyl trimethylsilylsuccinate, dineopentyl methoxysuccinate, dineopentyl cyclohexylsuccinate, dineopentyl (cyclohexylmethyl) succinate, dineopentyl t-butylsuccinate, dineopentyl isobutylsuccinate, dineopentyl isopropylsuccinate, dineopentyl neopentylsuccinate, dineopentyl isopentylsuccinate, and/or dineopentyl (l,l,l-trifluoro-2-propyl) succinate.

[00100] The internal electron donor having a structure consistent with formula (4) may comprise at least two radicals from R³ to R⁶, which are different from hydrogen and are selected from Ci to C20 linear or branched alkyl, alkenyl, and/or cycloalkyl hydrocarbyl groups, which may contain heteroatoms. Two radicals different from hydrogen may be linked to the same carbon atom. Suitable examples include 2,2-disubstituted succinates including diethyl-2, 2-dimethylsuccinate, diethyl-2-ethyl-2-methylsuccinate, diethyl-2-

(cyclohexylmethyl)-2-isobutylsuccinate, diethyl-2-cyclopentyl-2-n-propylsuccinate, diethyl-2, 2-diisobutylsuccinate, diethyl-2-cyclohexyl-2-ethylsuccinate, diethyl-2- isopropyl-2-methylsuccinate, diethyl-2, 2-diisopropyl-diethyl-2-isobutyl-2-ethylsuccinate, diethyl-2-(l,l,l-trifluoro-2-propyl)-2-methylsuccinate, diethyl-2 -isopentyl-2 - isobutylsuccinate, diisobutyl-2, 2-dimethylsuccinate, diisobutyl-2-ethyl-2-methylsuccinate, diisobutyl-2-(cyclohexylmethyl)-2-isobutylsuccinate, diisobutyl-2-cyclopentyl-2-n- propylsuccinate, diisobutyl-2, 2-diisobutylsuccinate, diisobutyl-2-cyclohexyl-2- ethylsuccinate, diisobutyl-2-isopropyl-2-methylsuccinate, diisobutyl-2-isobutyl-2- ethylsuccinate, diisobuty l-2-( 1 ,1,1 -trifluoro-2-propy l)-2-methy lsuccinate, diisobutyl-2- isopentyl-2-isobutylsuccinate, diisobutyl-2, 2-diisopropylsuccinate, dineopentyl-2, 2- dimethylsuccinate, dineopentyl-2-ethyl-2-methylsuccinate, dineopentyl-2-

(cyclohexylmethyl)-2-isobutylsuccinate, dineopentyl-2-cyclopentyl-2-n-propylsuccinate, dineopentyl-2, 2-diisobutylsuccinate, dineopentyl-2-cyclohexyl-2-ethylsuccinate, dineopentyl-2 -isopropyl-2-methylsuccinate, dineopentyl-2-isobutyl-2-ethylsuccinate, dineopentyl-2-(l ,1,1 -trifluoro-2-propyl)-2-methylsuccinate, dineopentyl 2,2- diisopropylsuccinate, and/or dineopentyl 2-isopentyl-2-isobutylsuccinate.

[00101] The at least two radicals different from hydrogen may be linked to different carbon atoms between R³ and R⁶ in formula (4). Examples include R³ and R⁵ or R⁴ and R⁶.

Suitable non-aromatic succinate compounds such as this include: diethyl-2, 3- bis(trimethylsilyl) succinate, diethyl-2, 2-sec-butyl-3-methylsuccinate, diethyl-2-(3,3,3- trifluoropropyl)-3-methylsuccinate, diethyl-2,3 -bis(2-ethylbutyl) succinate, diethyl-2, 3- diethyl-2-isopropylsuccinate, diethyl-2, 3-diisopropyl-2-methylsuccinate, diethyl-2, 3- dicyclohexyl-2-methylsuccinate, diethyl-2, 3 -diisopropy lsuccinate, diethyl-2, 3- bis(cyclohexylmethyl) succinate, diethyl-2, 3-di-t-butylsuccinate, diethyl-2, 3- diisobutylsuccinate, diethyl-2, 3-dineopentylsuccinate, diethyl-2, 3 -diisopenty lsuccinate, diethyl-2, 3-(l -trifluoromethyl-ethyl) succinate, diethyl-2-isopropyl-3-isobutylsuccinate, diethyl-2-t-butyl-3-isopropylsuccinate, diethyl-2 -isopropyl-3-cyclohexylsuccinate, diethyl-

2-isopentyl-3-cyclohexylsuccinate, diethyl-2-cyclohexyl-3-cyclopentylsuccinate, diethyl-

2, 2,3, 3-tetramethylsuccinate, diethyl-2, 2, 3, 3-tetraethylsuccinate, diethyl-2, 2,3,3- tetrapropylsuccinate, diethyl-2,3 -diethyl-2,3 -diisopropy lsuccinate, diisobutyl-2, 3- bis(trimethylsilyl) succinate, diisobutyl-2, 2-sec-butyl-3-methylsuccinate, diisobutyl-2- (3,3,3-trifluoropropyl)-3-methylsuccinate, diisobutyl-2, 3-bis(2-ethylbutyl) succinate, diisobutyl-2, 3-diethyl-2 isopropylsuccinate, diisobutyl-2, 3-diisopropyl-2-methylsuccinate, diisobutyl-2, 3-dicyclohexyl-2-methylsuccinate, diisobutyl-2, 3-diisopropylsuccinate, diisobutyl-2, 3-bis (cyclohexylmethyl) succinate, diisobutyl-2, 3-di-t-butylsuccinate, diisobutyl-2, 3-diisobutylsuccinate, diisobutyl-2, 3-dineopentylsuccinate, diisobutyl-2, 3- diisopentylsuccinate, diisobutyl-2, 3-(l,l,l-trifluoro-2-propyl) succinate, diisobutyl-2, 3-n- propylsuccinate, diisobutyl-2-isopropyl-3-isobutylsuccinate, diisobutyl-2-terbutyl-3- isopropylsuccinate, diisobutyl-2-isopropyl-3-cyclohexylsuccinate, diisobutyl-2-isopentyl- 3-cyclohexylsuccinate, diisobutyl-2-n-propyl-3-(cyclohexylmethyl) succinate, diisobutyl- 2-cyclohexyl-3-cyclopentylsuccinate, diisobutyl-2, 2, 3, 3-tetramethylsuccinate, diisobutyl-

2.2.3.3-tetraethylsuccinate, diisobutyl-2, 2, 3, 3-tetrapropylsuccinate, diisobutyl-2, 3-diethyl-

2.3-diisopropylsuccinate, dineopentyl-2, 3-bis(trimethylsilyl) succinate, dineopentyl-2, 2-di- sec-butyl-3-methylsuccinate, dineopentyl 2-(3,3,3-trifluoropropyl)-3-methylsuccinate, dineopentyl-2, 3-bis(2-ethylbutyl) succinate, dineopentyl 2,3-diethyl-2-isopropylsuccinate, dineopentyl-2, 3-diisopropyl-2-methylsuccinate, dineopentyl-2, 3-dicyclohexyl-2- methylsuccinate, dineopentyl-2, 3-diisopropylsuccinate, dineopentyl-2, 3- bis(cyclohexylmethyl) succinate, dineopentyl-2, 3-di-t-butylsuccinate, dineopentyl-2, 3- diisobutylsuccinate, dineopentyl-2, 3-dineopentylsuccinate, dineopentyl-2, 3- diisopentylsuccinate, dineopentyl 2,3-(l,l,l-trifluoro-2propyl) succinate, dineopentyl-2, 3- n-propylsuccinate, dineopentyl-2-isopropyl-3-isobutylsuccinate, dineopentyl-2-t-butyl-3- isopropylsuccinate, dineopentyl-2 -isopropyl-3-cyclohexylsuccinate, dineopentyl-2- isopentyl-3-cyclohexylsuccinate, dineopentyl-2-n-propyl-3-(cyclohexylmethyl) succinate, dineopentyl 2-cyclohexyl-3-cyclopentylsuccinate, dineopentyl-2, 2,3,3- tetramethylsuccinate, dineopentyl 2, 2, 3, 3-tetraethylsuccinate, dineopentyl-2, 2,3,3- tetrapropylsuccinate, and/or dineopentyl-2, 3-diethyl-2, 3-diisopropylsuccinate.

[00102] The electron donor according to formula (4) may include two or four of the radicals R³ to R⁶ joined to the same carbon atom which are linked together to form a cyclic multivalent radical. Examples of suitable compounds include l-(ethoxycarbonyl)-l- (ethoxyacetyl)-2,6-dimethylcyclohexane, l-(ethoxy carbonyl)- 1 -(ethoxy acetyl)-2, 5- dimethyl-cyclopentane, 1 -(ethoxy carbonyl)- 1 -(ethoxy acetylmethyl)-2-methylcy cl ohexane, and/or 1 -(ethoxy carbonyl)-! -(ethoxy (cyclohexyl) acetyl) cyclohexane. [00103] In some embodiments, the internal electron donor may be selected from the group consisting of diethyl-2, 3-diisopropylsuccinate, diisobutyl-2, 3-diisopropylsuccinate, di-n-butyl-2,3-diisopropylsuccinate, diethyl-2, 3-dicyclohexyl-2-methylsuccinate, diisobutyl-2, 3-dicyclohexyl-2-methylsuccinate, diisobutyl-2, 2-dimethylsuccinate, diethyl- 2, 2-dimethylsuccinate, diethyl-2-ethyl-2-methylsuccinate, diisobutyl-2-ethyl-2- methylsuccinate, diethyl-2-(cyclohexylmethyl)-3-ethyl-3-methylsuccinate, diisobutyl-2 - (cyclohexylmethyl)-3-ethyl-3-methylsuccinate, and combinations thereof.

[00104] In conjunction with an internal donor, two or more external electron donors may also use in combination with a catalyst. The external electron donors may comprise an organic silicon compound of the general formula (5):

R^!nSiCOR²)^, (5) wherein R¹ and R² independently represent ahydrocarbyl radical and n is 1, 2, or 3.

[00105] Examples of the suitable organic silicon compounds include trimethylmethoxysilane, trimethylethoxysilane, dimethyldimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diiso-propyldiethoxysilane, t-butylmethyl-n-diethoxysilane, t-butylmethyldiethoxysilane, t-amylmethyldiethoxysilane, diphenyldimethoxysilane, phenylmethyldimethoxysilane, diphenyldiethoxysilane, bis-o- tolyldimethoxysilane, bis-m-tolyldimethoxysilane, bis-p-tolyldimethoxysilane, bis-p- tolyldimethoxysilane, bisethylphenyldimethoxysilane, dicyclohexyldiethoxysilane, cyclohexylmethyl-dimethoxysilane, cyclohexylmethyldiethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyl-trimethoxysilane, methyltrimethoxysilane, n-propyl-triethoxysilane, decyltrimethoxysilane, decyltri ethoxy silane, phenyltrimethoxy silane, [gamma] -chloropropyltri-methoxy silane, methyltriethoxysilane, ethyltriethoxysilane, vinyltriethoxysilane, t-butyltriethoxysilane, n-butyltriethoxysilane, iso-butyltriethoxysilane, phenyltriethoxysilane, gamma- aminopropyltriethoxysilane, chlorotriethoxysilane, vinyltributoxysilane, cyclo- hexyltrimethoxysilane, cyclohexyltriethoxysilane, 2-norbomanetriethoxysilane,

2-norbomanemethyldimethoxysilane, ethyl silicate, butyl silicate, trimethyl-phenoxysilane, methylallyloxysilane, vinyltris(beta-methoxyethoxysilane), vinyltriacetoxysilane, dimethyltetraethoxydisiloxane, tetraethoxysilane, methylcyclohexyldimethoxysilane, propyltriethoxysilane, and/or dicyclopentyldimethoxysilane. [00106] In some embodiments, the external electron donors are selected from any one or more of methyltrimethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyltriethoxysilane, propyltrimethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, propyltriethoxysilane, butyltriethoxysilane, phenyltriethoxysilane, vinyltrimethoxysilane, vinyltributoxysilane cyclohexyltrimethoxysilane, tetraethoxysilane, methylcyclohexyldimethoxysilane, propyltriethoxysilane, and/or dicyclopentyldimethoxysilane.

[00107] The external electron donors act to control stereoregularity, which affects the amount of isotactic versus atactic polymers produced in a given system. The more stereoregular isotactic polymer is more crystalline, which leads to a material with a higher flexural modulus. Highly crystalline, isotactic polymers also display lower melt flow rates (MFRs), as a consequence of a reduced hydrogen response during polymerization. The stereoregulating capability and hydrogen response of a given external electron donor are typically directly and inversely related.

[00108] The herein described organic silicon compounds may be used such that a compound capable of being changed into such an organic silicon compound is added at the time of polymerizing or, if present, a pre-polymerization step, and the organic silicon compound may be formed in situ during the polymerization or the pre-polymerization. [00109] In any embodiment, the production of the polypropylene random copolymer may include the use of two external electron donors. Suitable methods for using such external electron donors is disclosed in US 6,087,459, and US 6,686,433. The two external electron donors may be selected from any of the external electron donors described herein. But in a particular embodiment, the first external electron donor has the formula R¹2Si(OR²)2, wherein each R¹ is independently a hydrocarbyl radical comprising from 1 to 10 carbon atoms in which the carbon adjacent to the Si is a secondary or a tertiary carbon atom, and wherein each R² is independently a hydrocarbyl radical comprising from 1 to 10 carbon atoms; and the second external electron donor has the formula R³ _nSi(OR⁴)4-_n, wherein each R³ and R⁴ are independently a hydrocarbyl radical comprising from 1 to 10 carbon atoms, and n is 1, 2, or 3; wherein the second external electron donor is different than the first external electron donor.

[00110] In any embodiment, the first external electron donor and the second external electron donor may be selected from the group consisting of tetraethoxysilane, methylcyclohexyldimethoxysilane, propyltriethoxysilane, dicyclopentydimethoxysilane, and combinations thereof. The Ziegler-Natta catalyst system may comprise 2.5 mol% to less than 10, or 20, or 30, or 40, or 50 mol% of the first external electron donor and greater than 50, or 60, or 70, or 80, or 90 mol% of a second external electron donor based on total mol% of external electron donors. The external electron donor(s) are preferably present to within a range from 1, or 10 ppm to 50, or 60, or 80, or 100 ppm in the polymerization system or reactor.

[00111] The polymerization process may include a “pre-polymerization” step. The pre-polymerization may include utilizing the Ziegler-Natta catalyst system comprising the non-aromatic internal electron donor in combination with at least a portion of the organoaluminum co-catalyst wherein at least a portion of the external electron donors are present wherein the catalyst system is utilized in a higher concentration than utilized in the subsequent “main” polymerization process.

[00112] The concentration of the catalyst system in the main and/or pre-polymerization stages may be from 0.01 to 200 millimoles, or more preferably from 0.05 to 100 millimoles, calculated as a titanium atom, per liter of an inert hydrocarbon medium. The organoaluminum co-catalyst may be present in an amount sufficient to produce from 0.1 to 500 g, or more preferably from 0.3 to 300 g, of a polymer per gram of the titanium catalyst present, and may be present at from 0.1 to 100 moles, or more preferably from 0.5 to 50 moles, per mole of the titanium atom present in the catalyst component.

[00113] The pre-polymerization, if carried out, may be performed under mild conditions in an inert hydrocarbon medium in which an olefin and the catalyst components are present. Examples of the inert hydrocarbon medium used include aliphatic hydrocarbons, such as propane, butane, pentane, hexane, heptane, octane, decane, dodecane and kerosene; alicyclic hydrocarbons, such as cyclopentane, cyclohexane and methylcyclopentane; aromatic hydrocarbons, such as benzene, toluene and xylene; halogenated hydrocarbons, such as ethylene chloride and chlorobenzene; and mixtures thereof. Such inert hydrocarbons can be used in the main polymerization process as well. Also, the olefin(s) used in the pre polymerization may be the same as an olefin to be used in the main polymerization. Most preferably propylene is used as the diluent. The reaction temperature for the pre polymerization may be a point at which the resulting pre-polymerization does not dissolve substantially in the inert hydrocarbon medium, which may be from -20 to +100°C, or from -20 to +80°C, or from 0 to 40°C. [00114] During the pre-polymerization, a molecular weight controlling agent such as hydrogen may be used. The molecular weight controlling agent may desirably be used in such an amount that the polymer obtained by pre-polymerization has properties consistent with the intended product. The pre-polymerization may be carried out so that from 0.1 to 1000 g, or more preferably from 0.3 to 300 g, of a polymer forms per gram of the titanium catalyst.

[00115] The main polymerization (“polymerization”) of the propylene and ethylene co-monomers may be carried out in the gaseous phase, the liquid phase, bulk phase, slurry phase, or any combination thereof. Preferably the polymerization is carried out by slurry polymerization wherein the inert hydrocarbon may be used as a reaction solvent, or an olefin liquid under the reaction conditions may be used as the solvent. Most preferably the propylene monomer is used as the diluent in the slurry polymerization process. The polymerization process includes contacting the titanium catalyst component, the one or more internal electron donors, the organoaluminum co-catalyst, and the two or more external electron donors with each other at the time of the polymerization, before the polymerization, for example, at the time of the pre-polymerization, or a combination thereof. In contacting them before the polymerization, any two or more of these components may be freely selected and contacted. Two or more of the components may be contacted individually or partly and then contacted with each other in total to produce the catalyst system. In any case, hydrogen may be used during polymerization to control the molecular weight and other properties of the resulting polymer.

[00116] In any embodiment, the polymerization conditions include a polymerization temperature within a range from 20, or 40, or 60°C to 120, or 140, or 160, or 180, or 200°C, and a pressure from atmospheric pressure up to 100 kg/cm², or more preferably within a range from 2, or 6 kg/cm² to 20, or 50, or 100 kg/cm². The polymerization process may be carried out batch-wise, semi-continuously, or continuously, and/or in two or more reactors in series. The conditions in each reactor, if carried out in more than one reactor, may be the same or different. The reaction slurry (e.g., homopolymer granules in bulk propylene) may then be removed from the reactor and the polymer granules continuously separated from the liquid propylene. The polymer granules may then be separated from the unreacted monomer to produce a granular product for compounding and/or mechanical properties

[00117] The polypropylene random copolymer is formed into the polymeric foam as described herein. In embodiments, a method of forming the polymeric foam described herein comprises heating the polypropylene random copolymer described herein; impregnating the polypropylene random copolymer with a foaming agent under a first pressure; and reducing the first pressure to a second pressure to form the polymeric foam. In embodiments, reducing the first pressure to the second pressure causes the foaming agent to form bubbles within the polypropylene random copolymer thereby forming the polymeric foam. In embodiments, impregnating the polypropylene random copolymer further comprises entrapping the foaming agent in the polypropylene random copolymer after impregnation. In embodiments, entrapping the foaming agent comprises slowly cooling the polypropylene random copolymer after impregnation below the copolymer’s crystallization temperature and slowly reducing the first pressure. In embodiments, heating the polypropylene random copolymer with entrapped foaming agent causes the foaming agent to form bubbles within the polypropylene random copolymer thereby forming the polymeric foam. For example, forming structural foamed items having a particular shape comprises injecting expanded polypropylene-based foam beads into a mold, following which pressure and steam heat fuse the beads into a finished shape.

[00118] In embodiments, heating the polypropylene random copolymer comprises heating at a temperature in a range of about 130°C to about 150°C; or about 135°C to about 145°C. In embodiments, the foaming agent is a gaseous agent, such as carbon dioxide, nitrogen, chlorofluorocarbons, hydrochlorofluorocarbons, propane, pentane, isobutene, air, or a combination thereof. In some embodiments, impregnating the polypropylene random copolymer with a foaming agent occurs over a saturation time in a range of about 5 min to about 120 min; or about 15 min to about 100 min; or about 25 min to about 80 min; or about 30 min to about 60 min. In another embodiment, the saturation time is in a range of about 5 min to about 15 hours; or about 120 min to about 15 hours; or about 5 hours to about 15 hours; or about 10 hours to about 15 hours.

[00119] In embodiments, the first pressure is maintained at a constant pressure. In embodiments, the first pressure is maintained at a pressure in a range of about 500 psi to about 5000 psi; or about 1000 psi to about 3500 psi; or about 1000 psi to about 2000 psi. In embodiments, reducing the first pressure to the second pressure causes the foaming agent to form bubbles within the polypropylene random copolymer thereby forming the polymeric foam. In embodiments, reducing the first pressure to the second pressure comprises reducing the first pressure at a rate of about 0.1 MPa/s to about 400 MPa/s; or about 1 MPa/s to about

300 MPa/s; or about 5 MPa/s to about 200 MPa/s; or about 50 MPa/s to about 100 MPa/s; or about 70 MPa/s to about 80 MPa/s. In another embodiment, the first pressure is reduced at a rate of about 0.001 MPa/s to about 400 MPa/s; or about 0.001 MPa/s to about 100 MPa/s; or about 0.001 MPa/s to about 25 MPa/s; or about 0.001 MPa/s to about 5 MPa/s; or about 0.001 MPa/s to about 0.1 MPa/s. In embodiments, the second pressure is approximately atmospheric pressure.

[00120] In any embodiment, the polypropylene random copolymer may first be blended with another polymer and/or additive (e.g., filler, anti-oxidant, etc.) prior to being formed into the polymeric foam. In embodiments, the additive may be talc or a nanoclay, or talc or a nanoclay in combination with a polymer, such as maleic anhydride grafted polypropylene (PPMA) (e.g., see Guo et al, Pol. Eng. Sci. 47:1070-1081, 2007). In embodiments, said additives are blended into the polypropylene random copolymer to provide a more homogeneous dispersion, etc. In embodiments, said additives are blended into the polypropylene random copolymer to enhance cell nucleation.

[00121] Thus formed, in any embodiment, the polymeric foam has a density in a range of about 0.02 g/cc to about 1 g/cc; or about 0.02 g/cc to about 0.9 g/cc; or about 0.02 g/cc to about 0.8 g/cc; 0.02 g/cc to about 0.7 g/cc; 0.02 g/cc to about 0.6 g/cc; 0.02 g/cc to about 0.5 g/cc; 0.02 g/cc to about 0.4 g/cc; 0.02 g/cc to about 0.3g/cc; 0.02 g/cc to about 0.2 g/cc; 0.02 g/cc to about 0.1 g/cc. In another embodiment, the polymeric foam has an open cell percentage in a range of about 1 to about 75; or about 1 to about 65, or about 1 to about 45, or about 1 to about 20, or about 1 to about 10. In any embodiment, the polymeric foam has a double crystal melting peak with a low melting peak in a temperature range of about 140°C to about 165°C; or about 145°C to about 155°C. In any embodiment, the polymeric foam has a double crystal melting peak with a high melting peak in a temperature range of about 150°C to about 175°C; or about 155°C to about 160°C.

[00122] In any embodiment, the polymeric foam further comprises (or consists essentially of, or consists of) a cell density in a range of about 10⁶ cells/cm³ to about 10⁹ cells/cm³; or about 10⁷ cells/cm³ to about 10⁹ cells/cm³; or about 10⁸ cells/cm³ to about 10⁹ cells/cm³. In any embodiment, the polymeric foam further comprises (or consists essentially of, or consists of) an expansion ratio in a range of about 1 to about 35; or about 1.1 to about

25, or about 1.1 to about 20, or about 1.1 to about 15, or about 1.1 to about 10, or about 1.1 to about 5. In any embodiment, the polymeric foam further comprises (or consists essentially of, or consists of) a melting enthalpy in a range of about 50 J/g to about 110 J/g; or about

70 J/g to about 110 J/g; about 80 J/g to about 110 J/g; about 90 J/g to about 110 J/g. In any embodiment, the polymeric foam further comprises (or consists essentially of, or consists of) comprising a compression modulus in a range of about 0.1 to about 3 MPa with a loss tangent as high as 0.3.

[00123] Foaming agents useful in forming the polymeric foam described herein may be normally gaseous, liquid or solid compounds or elements, or mixtures thereof. These foaming agents may be characterized as either physically-expanding or chemically decomposing. Of the physically expanding foaming agents, the term “normally gaseous” is intended to mean that the expanding medium employed is a gas at the temperatures and pressures encountered during the preparation of the foamable compound, and that this medium may be introduced either in the gaseous or liquid state as convenience would dictate. Such agents can be added to the polypropylene random copolymer by blending the dry polymer with the foaming agent followed by melt extrusion, or by blending the agents in the polymer melt during extrusion. The foaming agent, especially a gaseous agent, may be blended with the polymer melt as it exits the melt extruder or mold that is used for forming the foamed articles.

[00124] In embodiments, the foaming agent is a gaseous agent. In embodiments, the gaseous agent is carbon dioxide, nitrogen, chlorofluorocarbons, hydrochlorofluorocarbons, propane, pentane, isobutene, air, or a combination thereof.

[00125] Included among exemplary, normally gaseous and liquid foaming agents are the halogen derivatives of methane and ethane, such as methyl fluoride, methyl chloride, difluoromethane, methylene chloride, perfluoromethane, trichloromethane, difluoro- chloromethane, dichlorofluoromethane, dichlorodifluoromethane, trifluorochloromethane, trichloromonofluoromethane, ethyl fluoride, ethyl chloride, 2,2,2-trifluoro-l,l- dichloroethane, 1,1,1-trichloroethane, difluoro-tetrachloroethane, 1,1-dichloro-l- fluoroethane, 1 , 1 -difluoro- 1 -chloroethane, dichloro-tetrafluoroethane, chlorotrifluoroethane, trichlorotrifluoroethane, l-chloro-l,2,2,2-tetrafluoroethane, 1,1- difluoroethane, 1,1,1-trifluoroethane, 1,1,1,2-tetrafluoroethane, perfluoroethane, pentafluoroethane, 2,2-difluoropropane, 1,1,1-trifluoropropane, perfluoropropane, dichloropropane, difluoropropane, chloroheptafluoropropane, dichlorohexafluoropropane, perfluorobutane, perfluorocyclobutane, sulfur-hexafluoride, and mixtures thereof. Other normally gaseous and liquid foaming agents that may be employed are hydrocarbons and other organic compounds such as acetylene, ammonia, butadiene, butane, butene, isobutane, isobutylene, dimethylamine, propane, dimethylpropane, ethane, ethylamine, methane, monomethylamine, trimethylamine, pentane, cyclopentane, hexane, propane, propylene, alcohols, ethers, ketones, and the like. Inert gases and compounds, such as nitrogen, argon, neon or helium, can also be used as foaming agents.

[00126] Solid, chemically decomposable foaming agents, which decompose at elevated temperatures to form gasses, can be used to expand the polypropylene random copolymer. In general, the decomposable foaming agent will have a decomposition temperature (with the resulting liberation of gaseous material) from 130°C to 200, or 250, or 300, or 350°C. Exemplary chemical foaming agents include azodicarbonamide, p,p'-oxybis(benzene) sulfonyl hydrazide, p-toluene sulfonyl hydrazide, p-toluene sulfonyl semicarbazide, 5-phenyltetrazole, ethyl-5 -phenyltetrazole, dinitroso pentamethylenete-tramine, and other azo, N-nitroso, carbonate and sulfonyl hydrazide compounds as well as various acid/bicarbonate compounds which decompose when heated. Representative volatile liquid foaming agents include isobutane, difluoroethane or blends of the two. For decomposable solid foaming agents, azodicarbonamide is preferred, while for inert gasses, carbon dioxide is preferred.

[00127] In any embodiment, an article can be formed from the herein described polymeric foam comprising the polypropylene random copolymer. In any embodiment, there is an article comprising the herein described polymeric foam. In some embodiments, the article is an automotive part, a storage container, a cooler, or sporting equipment. In embodiments, there is a foamed article comprising a polymeric foam, the polymeric foam comprising: a polypropylene random copolymer having a flex modulus > 1100 MPa and a melting point temperature, T_m, of <160°C; a density in a range of about 0.02 g/cc to about 1 g/cc; an open cell percentage in a range of about 1 to about 75; and a double crystal melting peak with a low melting peak in a temperature range of about 140°C to about 165°C and a high melting peak in a temperature range of about 150°C to about 175°C. In embodiments, the foamed article is a molded foam. In embodiments, the foamed article is a foam molded or shaped for insertion or incorporation into a part of a device or article (e.g., an automotive part, sports equipment, impact protection, safety applications, building insulation, cooler, etc.). In embodiments, the foamed article is a foam cooler.

[00128] The art of producing foam structures is known, especially for styrenic compositions. Articles comprising the herein described polymeric foam; or foamed articles comprising the polymeric foam of the present disclosure may take physical configurations known in the art, such as regular or irregular molded items. [00129] Other useful forms of foamed or foamable objects known in the art include expandable or foamable particles, moldable foam particles, or beads, and articles formed by expansion and/or consolidation and fusing of such particles. In some embodiments, the polymeric foam described herein is an expanded polypropylene-based bead foam. In embodiments, the expanded polypropylene-based bead foam is a closed-cell bead foam. Articles manufactured from polymer bead foams comprise numerous foamed particles, which can be welded together into three dimensionally shaped products; for example, lightweight parts with complex geometries and a high dimensional accuracy. In some embodiments, said expanded polypropylene-based bead foam (e.g., as a polymeric foam) can be molded or welded together via steam-chest molding machine. To facilitate said molding or welding, it is beneficial for the expanded polypropylene-based bead foam to have a suitable double crystal melting peak comprising a high and a low temperature melting peaks. Melting of low-temperature peak crystals (Tm-low) contribute to fusing and sintering of individual beads. Unmolten high-temperature peak crystals (Tm-high) help to preserve overall cellular morphology and dimensional stability of a molded expanded polypropylene-based bead foam product. A narrow processing window between the two melting peaks can pose a challenge when setting a processing steam temperature during the molding process in steam-chest molding machine. A slight variation in steam temperature could cause Tm-high crystals to be affected, which may impact the overall cellular morphology of the beads, causing shrinkage of the molded expanded polypropylene-based bead foam product.

[00130] A person of skill in the art would recognize that the low melting peak and high melting peak of a polymeric foam comprising a double crystal melting peak is dependent at least on the conditions under which the polymer (of which the polymeric foam is comprised) is foamed (e.g., saturation time, temperature, pressure, pressure drop rate, as well as cooling or heating rate.); and that, as a result, a range of low and high melting peak temperatures may be observed for polymeric foams formed from the same polymer, depending on the foaming conditions. For example, polymeric foams formed from the same polymer may exhibit a low melting peak in a temperature range of, e.g., about 140°C to about 165°C, and a high melting peak in a temperature range of, e.g., about 150°C to about 175°C, depending on how the polymer is foamed. While such melting peak temperature ranges may appear to overlap, a skilled person would recognize that, for a particular polymeric foam, the low melting peak will be less than the high melting peak and the high melting peak will be higher than the low melting peak.

[00131] The polymeric foam as described herein demonstrated generation of a double crystal melting peak (DCMP), the value of which was found to reach up to about 17°C, or up to about 20 °C depending on saturation time and CO2 pressure. In embodiments, the polymeric foam has a double crystal melting peak with a low melting peak in a temperature range of about 140°C to about 165°C; or about 145°C to about 155°C. In any embodiment, the polymeric foam has a double crystal melting peak with a high melting peak in a temperature range of about 150°C to about 175°C; or about 155°C to about 170°C.

[00132] In any embodiment, the foamable article or polypropylene random copolymer may be cross-linked prior to expansion, such as for the process of free-radical initiated chemical cross-linking or ionizing radiation, or subsequent to expansion. Cross-linking subsequent to expansion may be effected if desired by exposure to chemical cross-linking agents or radiation or, when silane-grafted polymers are used, exposure to moisture optionally with a suitable silanolysis catalyst.

[00133] Illustrative, but non-limiting, of methods of combining the various ingredients of the foamable polypropylene random copolymer include melt-blending, diffusion-limited imbibition, liquid-mixing, and the like, optionally with prior pulverization or other particle-size reduction of any or all ingredients. Melt-blending may be accomplished in a batchwise or continuous process, and is preferably carried out with temperature control. Furthermore, many suitable devices for melt-blending are known to the art, including those with single and multiple Archimedean-screw conveying barrels, high-shear “Banbury” type mixers, and other internal mixers. The object of such blending or mixing, by means and conditions which are appropriate to the physical processing characteristics of the components, is to provide therein a uniform mixture. One or more components may be introduced in a step-wise fashion, either later during an existing mixing operation, during a subsequent mixing operation or, as would be the case with an extruder, at one or more downstream locations into the barrel.

[00134] In some embodiments, the polypropylene random copolymer of the polymeric foam as described herein will have a foaming agent incorporated therein, such as a decomposable or physically expandable chemical and/or physical blowing agent, so as to effect expansion in a mold upon exposure of the composition to the appropriate conditions of heat and, optionally, the sudden release of pressure. Articles comprising the herein described polymeric foam; or foamed articles comprising the polymeric foam of the present disclosure find many uses as foamed articles including automotive components, storage containers, insulation and other construction components, food containers, sports equipment (e.g., yoga rolls, etc.), and other domestic and commercial uses.

[00135] In any embodiment, articles comprising the herein described polymeric foam, or foamed articles comprising the polymeric foam of the present disclosure may be cross-linked to enhance performance (such as thermal stability and durability). In any embodiment, any of these articles may be cross-linked, which can be effected by any means, including but not limited to chemical cross-linking (using cross-linking agents containing sulfur, peroxide, amine, halide, etc.) and radiation induced cross-linking (using radiation types such as electrons, x-rays, ions, neutrons, gamma-radiation, and ultraviolet). In a most preferred embodiment however, the articles formed are not cross-linked.

[00136] To gain a better understanding of the invention described herein, the following examples are set forth. It should be understood that these examples are for illustrative purposes only. Therefore, they should not limit the scope of this invention in anyway.

[00137] EXAMPLES

[00138] Example 1 - Expanded Bead Polypropylene Foams With Enhanced Stiffness [00139] Experimental

[00140] Four examples of said polypropylene random copolymers (i.e., resins)with a C2% content between approximately 1.3wt% and 1.7wt% were made using slurry polymerization reactors in the presence of a Ziegler-Natta type catalyst with an external electron donor catalyst system having two external electron donors, the external electron donors being organosilanes (e.g. dicyclopentyldimethoxysilane (DCPMS) and propyltriethoxysilane (PTES)) . Two benchmark materials PP9513 and Ineos PP R08S-00 were included for comparison. The Ineos PP R08S-00 is used as an EPP material, whereas the PP9513 is a grade having similar characteristics.

[00141] See Tables 1-6 below, where Sample 1 is PRC-Sample 1, Sample 2 is

PRC-Sample 2, Sample 3 is PRC-Sample 3, and Sample 4 is PRC-Sample 4.

[00142] Molecular Weight Determinations: Given that polymers are a collection of individual molecules each having its own molecular weight, the expression of the molecular weight of the collective “polymer” takes several statistical forms. The number average molecular weight (Mn) of the polymer is given by the equation å m Mi /å m. where “M” is the molecular weight of each polymer “i”. The weight average molecular weight (Mw), z-average molecular weight (Mz), and Mz+1 value are given by the equation å m Mⁿ⁺¹ /å niMi", where for Mw, n=l, for Mz, n=2, and for Mz+1, n=3, where n, in the foregoing equations is the number fraction of molecules of molecular weight Mi. The expression “Mw/Mn” is the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn), while the “Mz/Mw” is the ratio of the Mz to the Mw, an indication of the amount of high molecular weight component to the polypropylene random copolymers. The z and z+1 averages are defined as described in John M Dealy, Daniel J Read, Ronald G Larson Structure and rheology of molten polymers: from structure to flow behavior and back again, 2018/2/12 Carl, Hansen Varlag GmbH Co KG.

[00143] The molecular weights distributions were measured by using a Tosoh EcoSEC High Temperature GPC instrument with a dual pump system, and a dual flow refractive index detector. Detector calibration is described in a paper by T. Sun, P. Brant, R. R. Chance, and W. W. Graessley, in 34(19) Macromolecules, 6812-6820 (2001) and references therein. Three high temperature TSK gel columns were used for the GPC tests herein. The nominal flow rate was 1.0 mL/min, and the nominal injection volume was 300 pL. The various transfer lines, columns, and differential refractometer (the DRI detector) were contained in an oven maintained at 160°C. Solvent for the experiment was prepared by dissolving 1.2 grams of butylated hydroxy toluene as an antioxidant in 4 liters of Aldrich reagent grade 1, 2, 4-tri chlorobenzene (“TCB”). The TCB mixture was then filtered through a 0.1 pm polytetrafluoroethylene filter. The TCB was then degassed with an online degasser before entering the GPC. Polymer solutions were prepared by placing dry polymer in a glass container, adding the desired amount of TCB, then heating the mixture at 160°C with continuous shaking for about 2 hours. All quantities were measured gravimetrically. The TCB densities used to express the polymer concentration in mass/volume units were 1.463 g/ml at 23°C and 1.0989 g/ml at 160°C. The injection concentration was 0.4 mg/ml. Prior to running each sample the DRI detector was flushed. The flow rate in the columns was then increased to 1.0 ml/minute, and the DRI was allowed to stabilize for 2 hours before injecting the first sample. The concentration, c, at each point in the chromatogram was calculated from the baseline-subtracted DRI signal, IDRI, using the following equation: c = KDRIIDRI /(dn/dc), where KDRI is a constant determined by calibrating the DRI, and dn/dc=0.104 is the incremental refractive index for the system. Units of molecular weight are expressed in kg/mole or g/mole, and intrinsic viscosity is expressed in dL/g.

[00144] In view of the foregoing, it was found that (units g/mol):

PRC-Sample 1: Mn=57859, Mw=354311, Mz=l 390877,

Mz+1=2839675, Mw/Mn=6.124, Mz/Mw=3.926

PRC-Sample 2: Mn=59078, Mw=270063, Mz=827324,

Mz+l=1520702, Mw/Mn=4.571, Mz/Mw=3.063

PRC-Sample 3: Mn=71529, Mw=396731, Mz=1587754,

Mz+1=3586348

PRC-Sample 4: Mn=84341, Mw=483057, Mz=l 980484,

Mz+l=4315974, Mw/Mn=5.727, Mz/Mw=4.1 [00145] Flexural Modulus: ASTM D790 tested using ISO 37, Type 3 tensile bar, test speed at 1 mm/min and span of 30 mm, where tensile bars were molded on a BOY injection molder with an injection pressure of 950 to 1100 psi, hold pressure of 900 to 1050 psi, plasticizing pressure of 150 psi, hold time of 10 sec, and 1.0 to 1.6 mm fdl cushion.

[00146] Compression molding: Each resin was compression molded at 185 °C for 10 min with 2000 psi of pressure. Then each resin was quenched in a water batch and dried for further characterizations and processes.

[00147] Batch foaming: Batch foaming experiments were carried out into a thermally regulated cylindrical chamber. The chamber was first heated to the temperature of interest, then each resin was introduced in the chamber. Immediately after, the chamber was sealed and a physical blowing agent, CO2, was introduced at a defined pressure. The pressure was regulated to stay constant all along the gas impregnation step. After a defined saturation time, the gas was released at a rate of approximately 76 MPa/s and the chamber was immediately quenched in a water bath. Then a foamed sample was recovered.

[00148] DSC For Foamed Samples: Experiments were conducted with a TA Instruments Q250 DSC under 50mL/min of nitrogen flow. About 6mg of material was heated from -50 °C to 200 °C at 10 ⁰C.min '. Only the first cycle was analysed in order to understand the foaming process impact on the physical chemistry of the resulting foamed material. Resulting thermograms were analyzed with the Trios software from TA Instruments. The reported temperature of the transition was then associated to the midpoint taken at the half height of the sigmoidal transition. [00149] DSC for Unfoamed samples (see Fig. 5 to 8): Peak melting point, T_m, (also referred to as melting point), peak crystallization temperature, Tc. (also referred to as crystallization temperature), heat of fusion (AHi or Hf), were determined using the following DSC procedure according to ASTM D3418-03. Differential scanning calorimetric (DSC) data was obtained using a TA Instruments model Q200 machine. Samples weighing approximately 5-10 mg were sealed in an aluminum hermetic sample pan. The DSC data was recorded by first gradually heating the sample to 200°C at a rate of 10°C/minute. The sample was kept at 200°C for 5 minutes, then cooled to 0°C at a rate of 10°C/minute, followed by an isothermal for 5 minutes and heating to 200°C at 10°C/minute. Both the first and second cycle thermal events were recorded. The melting temperatures reported here were obtained during the second heating cycle unless otherwise noted.

[00150] Density measurement: Resin densities were measured using a water displacement method according to ASTM D792. Expansion ratio F was calculated from the equation below, where p is density related to either a unfoamed or foamed material.

[00151] Gas pycnometer: Open/closed cell fractions of the foamed samples were determined with an Accupyc 1340 lOcc apparatus according to ASTM D6226. Displacement volume was measured by introducing nitrogen into the chamber at a pressure of 2.000 psig. Determined values were calculated from an average of three measurement cycles. An estimation of the open-cell percentage (Co) in the foam were determined from the equation below:

with Vg being the geometric volume and V_P being the volume calculated from the pycnometer.

[00152] Small angle oscillatory shear data of unfoamed resins: Data fitted with Carreau-Yasuda model (CY) depicted in FIG. 1. Dynamic shear melt rheological data were measured with an Advanced Rheometrics Expansion System (ARES-G2) from TA Instruments using parallel plates (diameter = 25 mm) in a dynamic mode under nitrogen atmosphere. For all experiments, the rheometer was thermally stable at 190°C for at least 30 minutes before inserting compression-molded sample of resin onto the parallel plates. To determine the samples viscoelastic behavior, frequency sweeps in the range from 0.1 to 628 rad/s were carried out at a temperature of 190°C under constant strain. Depending on the molecular weight and temperature, strains in the linear deformation range verified by strain sweep test were used. A nitrogen stream was circulated through the sample oven to minimize chain extension or cross-linking during the experiments. All the samples were compression molded at 190°C. A sinusoidal shear strain was applied to the material, and if the strain amplitude was sufficiently small, the material behaved linearly. It was shown that the resulting steady-state stress also oscillated sinusoidally at the same frequency but shifted by a phase angle d with respect to the strain wave. The stress lead the strain by d. For purely elastic materials d=0° (stress is in phase with strain) and for purely viscous materials, d=90° (stress leads the strain by 90° although the stress is in phase with the strain rate). For viscoelastic materials, 0 < d < 90.

[00153] Shear thinning: The shear thinning was described by the following parameters: Power Law Index (slope of the viscosity vs frequency in the power-law regime), transition index (parameter describing the transition between Newtonian plateau and power law region), consistency (characteristic relaxation time of the polymer, inverse to the frequency correspondent to the transition from Newtonian to power-law regime), Infinite-Rate Viscosity, Zero-Shear Viscosity as defined by fitting dependence of complex viscosity on angular frequency data by Carreau-Yasuda model using TA Instruments Trios v3.3.1.4246 software. In at least one embodiment, a propylene copolymer, as described herein, at 190°C and at frequency range between 0.1 and 628 rad/s has: a power law index, VICY, of from about 0.07 to about 0.21 ;

- transition index, acY, of from about 0.33 to about 0.42; consistency (characteristic time), key, of from about 0. Is to about 0.37 s; infinite-rate viscosity, h_¥og, of from about 19 to about 29 Pa.s; and

- zero-shear viscosity, ho,a, of from about 3600 Pa.s. to about 32000 Pa.s, as defined by fitting dependence of complex viscosity on angular frequency data by Carreau-Yasuda model using TA Instruments Trios v3.3.1.4246 software.

[00154] Data, as graphically depicted in, for example, FIG. 1, was fitted with the Carreau-Yasuda model with the following parameters: h * (w) - h_¥ fio - h

with h₀ as zero-shear viscosity, p_¥as infinite viscosity, k as consistency and n as power law index and an a parameter describing transition between Newtonian plateau and power law region.

[00155] Table 1: Summary of Carreau-Yasuda parameters obtained by fiting shear rheology data of the samples (25mm @ 190°C).

[00156] Dynamic temperature ramp data: Dynamic temperature ramp data for unfoamed and select foamed samples in tensile and compression mode, respectively, graphically depicted in FIG. 2 to 4, 9. [00157] Dynamic Mechanical Thermal Analysis data was measured with the Rheometric

Solid Analyzer (RSA-G2) from TA Instruments using compression clamp fixture, which imposes a sinusoidal strain on a sample in the compression mode as a function of temperature. For all experiments, the RSA-G2 was thermally stable at 25C for at least 20 minutes to allow the compression tool and FCO oven to equilibrate. Once the tools and oven had been equilibrated, the gap on the tool was zeroed, then the compression tool was moved to the loading gap (10mm) and the transducer tared before loading the sample onto the 8mm compression tool. All samples were prepared at least 24 hours prior to testing. The foamed samples were cut into 8mm diameter discs, unfoamed samples were 5mm X 50mm fdms. The sample was aligned and centered onto the compression tool, then tightened with a torque screwdriver (20cN.m). Once the sample was loaded the FCO oven was closed to allow the sample to equilibrate, and a slight force (10-50g) was applied on the foamed sample and lOg tension was applied to unfoamed samples to keep the sample taught throughout the test. To determine the Dynamic Mechanical Thermal Analysis properties, the temperature was lowered to the starting temperature at 25°C. At a fixed frequency (1Hz), and fixed strain (0.05%), the temperature was ramped up to 150°C at 2°C/min. This provided a list of material parameters such as storage modulus (E’), loss modulus (E”), and loss angle (otherwise referred to as loss tangent) (tan 5=E”/E’) as a function of temperature. Loss tangent (tan 5) can be calculated as a ratio between loss (E”) and storage (E’)modub. As opposed to storage modulus (E’), which is often used as a measure of stiffness, tan d is often used to measure energy dissipation; for example, the higher a value of tan d, the more energy that can be dissipated by a material at a certain temperature and at a certain oscillation frequency. Both moduli, and hence the tan d, are temperature and frequency dependent.

[00158] Table 2: Summary of properties acquired for the polypropylene random copolymers (resins)

* ASTM-D1238 ** ASTM-D3418-03: DSC data measured at heating/cooling rate of 10°C/min using procedure for unfoamed samples described above. Tm was collected on the second heating cycle.

[00159] Table 3: Properties acquired from foaming experiments for foamed articles comprising the polypropylene random copolymer PRC-Sample 1

[00160] Table 4: Properties acquired from foaming experiments for foamed articles comprising the polypropylene random copolymer PRC-Sample 2

[00161] Table 5: Properties acquired from foaming experiments for foamed articles comprising the benchmark material PP9513

[00162] Table 6: Rheological and Mechanical properties acquired in tensile and flex mode for the polypropylene random copolymers (resins)

[00163] The embodiments described herein are intended to be examples only. Alterations, modifications and variations can be effected to the particular embodiments by those of skill in the art. The scope of the claims should not be limited by the particular embodiments set forth herein, but should be construed in a manner consistent with the specification as a whole.

[00164] All publications, patents and patent applications mentioned in this specification are indicative of the level of skill those skilled in the art to which this invention pertains and are herein incorporated by reference to the same extent as if each individual publication patent, or patent application was specifically and individually indicated to be incorporated by reference.

[00165] The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modification as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

Claims

WHAT IS CLAIMED IS:

1. A polymeric foam comprising:

(i) a density in a range of about 0.02 g/cc to about 1 g/cc;

(ii) an open cell percentage in a range of about 1 to about 75; and

(iii) a double crystal melting peak with a low melting peak in a temperature range of about 140°C to about 165°C and a high melting peak in a temperature range of about 150°C to about 175°C.

2. The polymeric foam of claim 1, further comprising a cell density in a range of about 10⁶ cells/cm³ to about 10⁹ cells/cm³.

3. The polymeric foam of claim 1 or 2, further comprising an expansion ratio in a range of about 1 to about 35.

4. The polymeric foam of claim 3, wherein the expansion ratio is in a range of about 1.1 to about 25, or about 1.1 to about 20, or about 1.1 to about 15, or about 1.1 to about 10, or about 1.1 to about 5.

5. The polymeric foam of any one of claims 1 to 4, further comprising a melting enthalpy in a range of about 50 J/g to about 110 J/g.

6. The polymeric foam of claim 6, wherein the melting enthalpy is in a range of about 80 J/g to about 110 J/g.

7. The polymeric foam of any one of claims 1 to 6, further comprising a dynamic storage modulus in compression mode in a range of about 0.1 MPa to about 3MPa with a loss tangent in a range between 0.1 and 0.3 as measured at temperatures in a range of about 25°C to about 150°C.

8. The polymeric foam of any one of claims 1 to 7, wherein the density is in a range of about 0.03 g/cc to about 0.3 g/cc.

9. The polymeric foam of claim 8, wherein the density is in a range of about 0.8 g/cc to about 0.9 g/cc.

10. The polymeric foam of any one of claims 1 to 9, wherein the open cell percentage is in a range of about 1 to about 65, or about 1 to about 45.

11. The polymeric foam of claim 10, wherein the open cell percentage is in a range of about 1 to about 20, or about 1 to about 10.

12. The polymeric foam of any one of claims 1 to 11, wherein the double crystal melting peak has a low melting peak in a temperature range of about 145°C to about 155°C and a high melting peak in a temperature range of about 155°C to about 170°C.

13. The polymeric foam of any one of claims 1 to 12, wherein the polymeric foam is comprised of a polypropylene random copolymer.

14. The polymeric foam of claim 13, wherein the polymeric foam is further comprised of talc, a nanoclay, or a combination of a polymer with talc or a nanoclay.

15. The polymeric foam of claim 14, wherein the polymer is maleic anhydride grafted polypropylene.

16. The polymeric foam of any one of claims 13 to 15, wherein the polypropylene random copolymer has a flexural modulus > 1100 MPa.

17. The polymeric foam of claim 16, wherein the polypropylene random copolymer has a flexural modulus is in a range of about 1200 MPa to about 1400 MPa.

18. The polymeric foam of claim 17, wherein the flexural modulus is in a range of about 1200 MPa to about 1350 MPa.

19. The polymeric foam of any one of claims 13 to 18, wherein the polypropylene random copolymer has a melting point temperature, Tm, of <160°C.

20. The polymeric foam of any one of claims 13 to 18, wherein the polypropylene random copolymer has a melting point temperature, T_m, in a range of about 152°C to about 156°C.

21. The polymeric foam of any one of claims 13 to 20, wherein the polypropylene random copolymer has a crystallization temperature, T_c, of <115°C.

22. The polymeric foam of claim 21, wherein the crystallization temperature, T_c is in a range of about 100°C to about 111°C.

23. The polymeric foam of any one of claims 13 to 22, wherein the polypropylene random copolymer has a melt flow rate in a range of about 1 g/lOmin to about 10 g/lOmin (2.16kg at 230°C; ASTM-D1238).

24. The polymeric foam of claim 23, wherein the melt flow rate is in a range of about 4 g/lOmin to about 10 g/lOmin (2.16kg at 230°C; ASTM-D1238).

25. The polymeric foam of claim 23 or 24, wherein the melt flow rate is in a range of about 6 g/lOmin to about 10 g/lOmin (2.16kg at 230°C; ASTM-D1238).

26. The polymeric foam of any one of claims 13 to 25, wherein the polypropylene random copolymer has a melt strength in a range of about 5 cN to about 25 cN.

27. The polymeric foam of any one of claims 13 to 26, wherein the polypropylene random copolymer has a tensile strain at break in a range of about 415% to about 485%.

28. The polymeric foam of any one of claims 13 to 27, wherein the polypropylene random copolymer has a tensile stress at break in a range of about 15 MPa to about 40 MPa.

29. The polymeric foam of any one of claims 13 to 28, wherein the polypropylene random copolymer has a Young’s modulus in a range of about 1500 MPa to about 1900 MPa.

30. The polymeric foam of any one of claims 13 to 29, wherein the polypropylene random copolymer has a tensile stress at yield in a range of about 30 MPa to about 40 MPa.

31. The polymeric foam of any one of claims 13 to 30, wherein the polypropylene random copolymer has a tensile strain at yield in a range of about 0.07 mm/mm to about 0.15 mm/mm.

32. The polymeric foam of any one of claims 13 to 31, wherein the polypropylene random copolymer has a zero-shear viscosity in a range of about 3500 Pa.s to about 33000 Pa s.

33. The polymeric foam of any one of claims 13 to 32, wherein the polypropylene random copolymer has a M_n in a range of about 55,000 g/mole to about 90,000 g/mole.

34. The polymeric foam of any one of claims 13 to 33, wherein the polypropylene random copolymer has a M in a range of about 250,000 g/mole to about 500,000 g/mole.

35. The polymeric foam of any one of claims 13 to 34, wherein the polypropylene random copolymer has a M /M_n in a range of about 3 to about 7.

36. The polymeric foam of any one of claims 13 to 35, wherein the polypropylene random copolymer has a M_z in a range of about 800,000 g/mole to about 2,000,000 g/mole.

37. The polymeric foam of any one of claims 13 to 36, wherein the polypropylene random copolymer has a Mz/M in a range of about 2 to about 5.

38. The polymeric foam of any one of claims 13 to 37, wherein the polypropylene random copolymer has a Mz_+i in a range of about 1,000,000 g/mole to about 5,000,000 g/mole.

39. The polymeric foam of any one of claims 13 to 38, wherein the polypropylene random copolymer has a dynamic storage compression modulus in a range of about 5 MPa to about 5 GPa and a loss tangent in a range between about 0.01 and 0.1 as measured at temperatures in a range of about -25 °C to about 150 °C.

40. The polymeric foam of any one of claim 13 to 39, wherein the polypropylene random copolymer is comprised of propylene and ethylene derived units.

41. The polymeric foam of claim 40, wherein the polypropylene random copolymer is comprised of <2 wt% of ethylene derived units.

42. A method of forming the polymeric foam of any one of claims 13 to 41, the method comprising: heating the polypropylene random copolymer; impregnating the polypropylene random copolymer with a foaming agent under a first pressure; and reducing the first pressure to a second pressure to form the polymeric foam.

43. The method of claim 42, wherein reducing the first pressure to the second pressure causes the foaming agent to form bubbles within the polypropylene random copolymer thereby forming the polymeric foam.

44. The method of claim 42 or 43, wherein the foaming agent is a gaseous agent.

45. The method of claim 44, wherein the gaseous agent is carbon dioxide, nitrogen, chlorofluorocarbons, hydrochlorofluorocarbons, propane, pentane, isobutene, air, or a combination thereof.

46. The method of any one of claims 42 to 45, wherein heating the polypropylene random copolymer comprises heating at a temperature in a range of about 130°C to about 150°C.

47. The method of claim 46, wherein the temperature is in a range of about 135°C to about 145°C.

48. The method of any one of claims 42 to 47, wherein impregnating the polypropylene random copolymer with a foaming agent occurs over a saturation time in a range of about 5 min to about 120 min.

49. The method of any one of claims 42 to 48, wherein, when impregnating the polypropylene random copolymer with a foaming agent, the first pressure is maintained at a constant pressure.

50. The method of claim 49, wherein the first pressure is maintained at a pressure in a range of about 500 psi to about 5000 psi.

51. The method of any one of claims 42 to 50, wherein reducing the first pressure to the second pressure comprises reducing the first pressure at a rate of about 0.1 MPa/s to about

400 MPa/s.

52. The method of any one of claims 42 to 51, wherein the second pressure is approximately atmospheric pressure.

53. An article comprising the polymeric foam of any one of claims 1 to 41.

54. The article of claim 53, wherein the article is an automotive part.

55. The article of claim 54, wherein the article is a storage container.

56. The article of claim 55, wherein the article is sporting equipment.

57. A foamed article, comprising: a polymeric foam, the polymeric foam comprising:

(ii) a density in a range of about 0.02 g/cc to about 1 g/cc;

(iii) an open cell percentage in a range of about 1 to about 75; and

58. The foamed article of claim 57, wherein the polymeric foam further comprises a cell density in a range of about 10⁶ cells/cm³ to about 10⁹ cells/cm³.

59. The foamed article of claim 57 or 58, wherein the polymeric foam further comprises an expansion ratio of in a range of about 1 to about 35, or about 1.1 to about 20, or about 1.1 to about 15, or about 1.1 to about 10, or about 1.1 to about 5.

60. The foamed article of any one of claims 57 to 59, wherein the polymeric foam further comprises a melting enthalpy in a range of about 50 J/g to about 110 J/g, or about 80 J/g to about 110 J/g.

61. The foamed article of any one of claims 57 to 60, wherein the polymeric foam further comprises a dynamic storage compression modulus in a range of about 0.1 to about 3 MPa and loss tangent in a range between 0.1 and 0.3.

62. The foamed article of any one of claims 57 to 61, wherein the density is in a range of about 0.03 g/cc to about 0.3 g/cc.

63. The foamed article of any one of claims 57 to 61, wherein the density is in a range of about 0.3 g/cc to about 0.9 g/cc, or about 0.8 g/cc to about 0.9 g/cc.

64. The foamed article of any one of claims 57 to 63, wherein the open cell percentage is in a range of about 1 to about 65, or about 1 to about 45, or about 1 to about 20, or about 1 to about 10.

65. The foamed article of any one of claims 57 to 64, wherein the flexural modulus is about 1200 MPa to about 1400 MPa, or about 1200 MPa to about 1350 MPa.

66. The foamed article of any one of claims 57 to 65, wherein the polypropylene random copolymer has a crystallization temperature, Tc, of <115°C.

67. The foamed article of any one of claims 57 to 66, wherein the polypropylene random copolymer has a crystallization temperature, Tc, is in a range of about 100°C to about 111 °C.

68. The foamed article of any one of claims 57 to 67, wherein the T_m is in a range of about 152°C to about 156°C.

69. The foamed article of any one of claims 57 to 68, wherein the polypropylene random copolymer has a melt flow rate in a range of about 1 g/lOmin to about 10 g/lOmin, or about 4 g/lOmin to about 10 g/lOmin, or about 6 g/lOmin to about 10 g/lOmin (2.16kg at 230°C; ASTM-D1238).

70. The foamed article of any one of claims 57 to 69, wherein the polypropylene random copolymer has a melt strength in a range of about 5 cN to about 25 cN.

71. The foamed article of any one of claims 57 to 70, wherein the polypropylene random copolymer has a tensile strain at break in a range of about 415% to about 485%.

72. The foamed article of any one of claims 57 to 71, wherein the polypropylene random copolymer has a tensile stress at break in a range of about 15 MPa to about 40 MPa.

73. The foamed article of any one of claims 57 to 72, wherein the polypropylene random copolymer has a Young’s modulus in a range of about 1500 MPa to about 1900 MPa.

74. The foamed article of any one of claims 57 to 73, wherein the polypropylene random copolymer has a tensile stress at yield in a range of about 30 MPa to about 40 MPa.

75. The foamed article of any one of claims 57 to 74, wherein the polypropylene random copolymer has a tensile strain at yield in a range of about 0.07 mm/mm to about 0.15 mm/mm.

76. The foamed article of any one of claims 57 to 75, wherein the polypropylene random copolymer has a zero-shear viscosity in a range of about 3500 Pa.s to about 33000 Pa.s.

77. The foamed article of any one of claims 57 to 76, wherein the polypropylene random copolymer has a M_n in a range of about 55,000 g/mole to about 90,000 g/mole.

78. The foamed article of any one of claims 57 to 77, wherein the polypropylene random copolymer has a M in a range of about 250,000 g/mol. to about 500,000 g/mol.

79. The foamed article of any one of claims 57 to 78, wherein the polypropylene random copolymer has a M /M_n in a range of about 3 to about 7.

80. The foamed article of any one of claims 57 to 79, wherein the polypropylene random copolymer has a M_z in a range of about 800,000 g/mol. to about 2,000,000 g/mol.

81. The foamed article of any one of claims 57 to 80, wherein the polypropylene random copolymer has a M_z/M in a range of about 2 to about 5.

82. The foamed article of any one of claims 57 to 81, wherein the polypropylene random copolymer has a M_z+i in a range of about 1,000,000 g/mol. to about 5,000,000 g/mol.

83. The foamed article of any one of claims 57 to 82, wherein the polypropylene random copolymer has a dynamic storage compression modulus in a range of about 5 MPa to about 5 GPa and loss tangent in a range between about 0.01 and 0.1 as measured at temperatures in a range of about -25 °C to about 150 °C.

84. The foamed article of any one of claims 57 to 83, wherein the polypropylene random copolymer is comprised of propylene and ethylene derived units.

85. The foamed article of claim 84, wherein the polypropylene random copolymer is comprised of <2 wt% of ethylene derived units.

86. The foamed article of any one of claims 57 to 85, wherein the polymeric foam further comprises talc, a nanoclay, or a combination of a polymer with talc or a nanoclay.

87. The foamed article of claim 86, wherein the polymer is maleic anhydride grafted polypropylene.