PHA-based microporous articles and methods for forming same

Abstract

PHA-based microporous articles are provided that have sufficient thermal and mechanical properties for many applications. A method for forming a porous expanded PHA composite comprising a porous PHA material includes depositing a partially crystalline polyhydroxyalkanoate (PHA) polymer onto a substrate at a deposition temperature below the melting temperature of the PHA polymer to form a PHA-substrate composite, and stretching the PHA-substrate composite at a temperature between the glass transition temperature of the PHA polymer and the melting temperature of the PHA polymer.

Description

[Technical Field]

[0001] The present disclosure relates generally to devices, systems, and methods for forming polyhydroxyalkanoate (PHA)-based microporous articles. More specifically, the present disclosure relates to devices, systems, and methods for forming PHA-based microporous articles having nodes and fibrils using below-melt processing approaches. [Background technology]

[0002] Polyhydroxybutyrate (PHB), a subfamily of polyhydroxyalkanoates (PHAs), is a biodegradable and biocompatible aliphatic polyester. PHA is a thermoplastic polymer, a linear polyester that can be produced naturally by various microorganisms or chemically synthesized. PHA is considered a fully recyclable material due to its biodegradation pathway in the environment.

[0003] PHB materials have poor mechanical properties and tend to be hard and brittle due to their high stereoregularity, crystallinity, and the formation of large spherulites. PHB materials also have a narrow heat-processable temperature range because their thermal decomposition temperature is close to their melting point. In addition, PHB materials have low melt strength, which makes melt processing difficult. Summary of the Invention [Problem to be solved by the invention]

[0004] Common approaches to overcome these challenges include the use of low molecular weight PHAs, blending with nucleating agents / other polymers, and the use of more expensive PHA copolymers with limited thermal properties to improve processability and their ultimate mechanical properties. However, these approaches inherently limit the maximum achievable mechanical properties, and the additional materials used can significantly impact biodegradability, biocompatibility, cost, and potential processing routes, thereby limiting their suitability in a variety of demanding applications.

[0005] PHAs can also be synthesized by chemical catalysts (Westlie et al. Synthetic biodegradable polyhydroxyalkanoates (PHAs): Recent advances and future challenges, Progress in Polymer Science 134(2022) 101608). Chemical catalyst synthesis routes allow for fine tuning of the thermal and mechanical properties of polyester resins by manipulating the polymer 3D microstructure, topology, and pendant group structure. The chemical catalyst route to PHAs has several advantages: (i) precision of synthesis (chain length (M n (ii) control of polymer stereomicrostructure (isotacticity, syndiotacticity, atacticity, stereoblock tacticity, and R or S configuration), molecular catalyst architecture (symmetry and asymmetry; stereoselectivity), and copolymer structure; and (iii) scalability and speed of production (ease of processing and high reaction rates typically associated with catalytic ring-opening polymerization (ROP) methods) (Westlie et al., supra). Mono- or di-substituted alkyl or aryl groups on the α-hydrogen of the PHA monomer enhance the thermal stability of the resulting PHA polymer by suppressing cis-elimination (Zhou et al., Science 380, 64-69 (2023)). Examples of such substituted PHA polymers include, but are not limited to, poly(3-hydroxy-2,2-dimethylbutyrate) (P3H(Me)2B), poly(3-hydroxy-2,2-diethylbutyrate) (P3H(Et)2B). However, there remains a need for microporous PHA-based articles that have sufficient thermal and mechanical properties for many applications. [Means for solving the problem]

[0006] According to one embodiment (“Embodiment 1”), a method includes heating a partially crystalline polyhydroxyalkanoate (PHA) polymer to a temperature above the melting temperature (T m) onto the substrate at a deposition temperature below the glass transition temperature (T) of the PHA polymer to form a PHA-substrate composite; g ) and the melting temperature (T m ) to form a porous expanded PHA composite, the porous expanded PHA composite comprising a porous PHA material having a microstructure, the microstructure comprising a plurality of nodes and a plurality of fibrils interconnecting the plurality of nodes, each fibril defining a fibril axis.

[0007] According to yet another embodiment ("Embodiment 2") of Embodiment 1, the fibrils comprise extended chain crystals (ECC) of the PHA polymer oriented along the fibril axis, and the extended chain crystals of the PHA polymer are the T of the PHA polymer before stretching. m It has a higher melting temperature than

[0008] According to yet another embodiment ("Embodiment 3") to Embodiment 1 or Embodiment 2, depositing a partially crystallized PHA polymer includes dissolving the PHA polymer in a solvent to form a PHA solution, casting the PHA solution onto a substrate, and at least partially crystallizing the PHA polymer by partially removing the solvent, adjusting the deposition temperature, or a combination thereof.

[0009] According to yet another embodiment ("Embodiment 4") to any one of Embodiments 1-3, the method further comprises the step of separating the porous PHA material from the porous expanded PHA composite to form a self-supporting porous PHA material.

[0010] According to yet another embodiment ("embodiment 5") in addition to any one of embodiments 1 to 4, the self-supporting porous PHA material has a porosity of 25% to 99%.

[0011] According to yet another embodiment ("Embodiment 6") to any one of Embodiments 1-5, the self-supporting porous PHA material is in the form of a membrane, a tube, a sheet, or a three-dimensional shape.

[0012] According to yet another embodiment ("Embodiment 7") to any one of Embodiments 1-6, the self-supporting porous PHA material has a matrix tensile strength of at least 5 MPa in the machine direction (MD) and / or transverse direction (TD).

[0013] According to yet another embodiment ("Embodiment 8") to any one of Embodiments 1 to 7, the total surface area of ​​the self-supporting porous PHA material per unit mass is 20 m 2 / g~80m 2 / g.

[0014] According to yet another embodiment ("Embodiment 9") of any one of Embodiments 1 to 8, the PHA-substrate complex is prepared by dissolving the PHA polymer in a T m Stretch at a temperature 10°C lower than the above.

[0015] According to yet another embodiment ("embodiment 10") to any one of embodiments 1-9, the PHA-substrate composite is stretched uniaxially, biaxially, or radially.

[0016] According to yet another embodiment ("embodiment 11") in addition to any one of embodiments 1 to 10, the PHA-substrate composite is stretched at a speed of 1% / s to 1000% / s.

[0017] According to yet another embodiment ("embodiment 12") of any one of embodiments 1 to 11, the PHA-substrate composite has a stretch ratio of 1:1.1 to 1:100.

[0018] According to yet another embodiment (“Embodiment 13”) of any one of Embodiments 1-12, the PHA polymer comprises a monomer, homopolymer, or copolymer comprising 3-hydroxybutyrate, 3-hydroxyvalerate, 4-hydroxybutyrate, 3-hydroxyhexanoate, or any combination thereof.

[0019] According to yet another embodiment (“Embodiment 14”) to any one of Embodiments 1-13, the PHA polymer is poly(3-hydroxybutyrate) (PHB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly(4-hydroxybutyrate) (P4HB), poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB4HB), or poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) P(3HB-co-3HHx).

[0020] According to yet another embodiment ("Embodiment 15") to any one of embodiments 1 to 14, the method further includes a step of forming a modified PHA article by treating the porous expanded PHA composite or self-supporting porous PHA material, where the treatment includes coating, imbibing, laminating, or any combination thereof, and the modified PHA article is porous or non-porous.

[0021] According to yet another embodiment ("Embodiment 16") to any one of embodiments 1 to 15, the method further includes densifying the porous expanded PHA composite, the porous self-supporting porous PHA material, or the modified PHA article to form a densified PHA material.

[0022] According to yet another embodiment ("Embodiment 17") to Embodiment 16, the densified PHA material includes a detectable endotherm associated with the presence of extended chain crystals in the PHA polymer.

[0023] According to yet another embodiment ("Embodiment 18") to Embodiment 16 or Embodiment 17, the densification comprises application of heat, application of pressure, stretching, or any combination thereof.

[0024] According to yet another embodiment ("embodiment 19") of any one of embodiments 1-16, the PHA polymer further comprises at least one porogen prior to deposition onto the substrate.

[0025] According to yet another embodiment ("embodiment 20") to embodiment 19, the method further comprises removing the porogen before or after stretching the PHA-substrate composite.

[0026] According to yet another embodiment ("embodiment 21") in addition to any one of embodiments 1 to 16, the substrate is a deformable substrate.

[0027] According to yet another embodiment ("embodiment 22") to embodiment 21, the deformable substrate is a stretchable polymer.

[0028] According to yet another embodiment ("Aspect 23") relative to embodiment 21 or embodiment 22, the deformable substrate comprises a member selected from polytetrafluoroethylene (PTFE) tape, PTFE film, polyolefin tape, polyolefin film, expanded polyolefin film, ultra-high molecular weight polyethylene (UHMWPE) tape, UHMWPE film, and expanded UHMWPE film.

[0029] According to one embodiment ("Embodiment 24"), there is provided a porous polyhydroxyalkanoate (PHA) material formed from a PHA polymer having a microstructure including a plurality of nodes and a plurality of fibrils interconnecting the plurality of nodes, the fibrils defining a fibril axis.

[0030] According to yet another embodiment ("Embodiment 25") to embodiment 24, the fibrils comprise a plurality of extended chain crystals of the PHA polymer oriented along the fibril axis, the extended chain crystals of the PHA polymer being in a T state of the PHA polymer prior to stretching. m It has a higher melting temperature than

[0031] According to yet another embodiment ("embodiment 26") to embodiment 24 or embodiment 25, the PHA polymer has a molecular weight of 30,000 g / mol to 10,000,000 g / mol.

[0032] According to yet another embodiment ("embodiment 27") in addition to any one of embodiments 24 to 26, the porous PHA material has a porosity of 25% to 99%.

[0033] According to yet another embodiment ("embodiment 28") to any one of embodiments 24-27, the porous PHA material is in the form of a membrane, a tube, a sheet, or a three-dimensional shape.

[0034] According to yet another embodiment ("Embodiment 29") of any one of Embodiments 24-28, the porous PHA material has a matrix tensile strength of at least 5 MPa in the machine direction (MD) and / or transverse direction (TD).

[0035] According to yet another embodiment ("Embodiment 30") of any one of Embodiments 24-29, the total surface area of ​​the porous PHA material per unit mass is 20 m 2 / g or greater.

[0036] According to yet another embodiment (“Embodiment 31”) of any one of embodiments 24-30, the PHA polymer comprises a monomer, homopolymer, or copolymer comprising 3-hydroxybutyrate, 3-hydroxyvalerate, 4-hydroxybutyrate, 3-hydroxyhexanoate, or any combination thereof.

[0037] According to yet another embodiment (“Embodiment 32”) of any one of embodiments 24-31, the PHA polymer is poly(3-hydroxybutyrate) (PHB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly(4-hydroxybutyrate) (P4HB), poly(3-hydroxybutyrate-co-4-hydroxybutyrate), or poly(3-hydroxybutyrate-co-hydroxyhexanoate) P(HB-co-HHx).

[0038] According to yet another embodiment ("Embodiment 33") of any one of embodiments 24-32, the PHA polymer is blended with an additional polymer selected from polylactic acid (PLA), polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), cellulose, polyglycolic acid (PGA), polycaprolactone (PCL), polyvinyl acetate (PVAc), chitin, chitosan, starch, and any combination thereof.

[0039] According to one embodiment ("Embodiment 34"), the composite comprises the porous PHA material of any one of Embodiments 24-33.

[0040] According to yet another embodiment ("embodiment 35") to embodiment 34, the PHA complex is microporous.

[0041] According to one embodiment ("Embodiment 36"), an article includes the porous PHA material of any one of Embodiments 24-33, or a composite of Embodiments 34 and 35.

[0042] According to yet another embodiment ("embodiment 37") to embodiment 36, the article includes a woven or nonwoven support substrate.

[0043] According to one embodiment ("Embodiment 38"), a material comprises a densified expanded polyhydroxyalkanoate having a detectable endotherm associated with the presence of residual extended chain crystals of the PHA polymer, and the material has a porosity of less than 10%.

[0044] According to one embodiment (“Embodiment 39”), the porous polyhydroxyalkanoate (PHA) material has Formula I: [ka] or Formula II: [ka] wherein R1 and R2 are independently H, or C1-C6 alkyl, or aryl; R3 is C1-C4 alkyl; X is 2-4; and n=3000-100,000, and the porous PHA material has a fibrillated microstructure that includes only a plurality of nodes or fibrils interconnected by fibrils, the fibrils having an orientation that defines a fibril axis.

[0045] According to yet another embodiment ("Embodiment 40") to embodiment 39, the fibrils comprise a plurality of extended chain crystals of the PHA polymer oriented along the fibril axis, the extended chain crystals of the PHA polymer being in a T state of the PHA polymer prior to stretching. m It has a higher melting temperature than

[0046] According to yet another embodiment ("embodiment 41") to embodiment 39 or embodiment 40, the PHA polymer has a molecular weight of 30,000 g / mol to 10,000,000 g / mol.

[0047] According to yet another embodiment ("embodiment 42") of any one of embodiments 39 to 41, the porous PHA material has a porosity of 25% to 99%.

[0048] According to yet another embodiment ("embodiment 43") of any one of embodiments 39-42, the porous PHA material is in the form of a membrane, a tube, a sheet, a monofilament, or a three-dimensional shape.

[0049] According to yet another embodiment ("embodiment 44") of any one of embodiments 39-43, the porous PHA material has a matrix tensile strength of at least 5 MPa in the machine direction (MD) and / or transverse direction (TD).

[0050] According to yet another embodiment ("Embodiment 45") of any one of Embodiments 39 to 44, the total surface area of ​​the porous PHA material per unit mass is 20 m 2 / g or greater.

[0051] According to yet another embodiment ("Embodiment 46") to any one of embodiments 39-45, the PHA polymer comprises a monomer, homopolymer, or copolymer comprising 3-hydroxybutyrate, 3-hydroxyvalerate, 4-hydroxybutyrate, 3-hydroxyhexanoate, 3-hydroxy-2,2-dimethylbutyrate, 3-hydroxy-2-methylbutyrate, 3-hydroxy-2-ethylbutyrate, 3-hydroxy-2-methyl-2-ethylbutyrate, 3-hydroxy-2,2-diethylbutyrate, or any combination thereof.

[0052] According to yet another embodiment (“Embodiment 47”) of any one of embodiments 39-46, the PHA polymer is poly(3-hydroxybutyrate) (PHB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly(4-hydroxybutyrate) (P4HB), poly(3-hydroxybutyrate-co-4-hydroxybutyrate), poly(3-hydroxybutyrate-co-hydroxyhexanoate) P(HB-co-HHx), poly(3-hydroxy-2,2-dimethylbutyrate), poly(3-hydroxy-2-methylbutyrate), poly(3-hydroxy-2-ethylbutyrate), poly(3-hydroxy-2,2-diethylbutyrate), or poly(3-hydroxybutyrate-co-4-hydroxybutyrate).

[0053] According to yet another embodiment ("Embodiment 48") of any one of embodiments 39-47, the PHA polymer is blended with an additional polymer selected from polylactic acid (PLA), polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), cellulose, polyglycolic acid (PGA), polycaprolactone (PCL), polyvinyl acetate (PVAc), chitin, chitosan, starch, and any combination thereof.

[0054] According to one embodiment ("Embodiment 49"), a composite comprises the porous PHA material of any one of Embodiments 39-48.

[0055] According to yet another embodiment ("embodiment 50") to embodiment 49, the PHA complex is microporous.

[0056] According to one embodiment (“Embodiment 51”), an article includes the porous PHA material of any one of Embodiments 39-48, or the composite of Embodiment 49 or Embodiment 50.

[0057] According to yet another embodiment ("embodiment 52") to embodiment 51, the article is in the form of a membrane, a tube, a sheet, a monofilament article, or a three-dimensional shape.

[0058] According to yet another embodiment ("embodiment 53") to embodiment 52, the monofilament article is dental floss, medical suture, or fishing line.

[0059] According to yet another embodiment ("embodiment 54") to embodiment 51, the article includes a woven or nonwoven support substrate.

[0060] According to one embodiment (“Embodiment 55”), a woven or knitted fabric comprises the porous PHA of any one of Embodiments 39-48.

[0061] According to one embodiment ("Embodiment 56"), a wearable garment comprises the woven or knit fabric of Embodiment 55. [Brief explanation of the drawings]

[0062] The accompanying drawings are included to provide a further understanding of the present disclosure, are incorporated in and constitute a part of this specification, illustrate embodiments, and together with the description, help to explain the principles of the present disclosure. The drawings are not necessarily to scale and may be exaggerated to show various aspects of the disclosure, and in that regard, the drawings should not be construed as limiting.

[0063] [Figure 1]1A and 1B are scanning electron microscope (SEM) images at two different magnifications of the porous poly(3-hydroxybutyrate) membrane produced in Example 11 according to embodiments disclosed herein.

[0064] [Figure 2] 1A and 1B are scanning electron microscope (SEM) images at two different magnifications of the porous poly(3-hydroxybutyrate) membrane produced in Example 12 according to embodiments disclosed herein.

[0065] [Figure 3] 1A and 1B are scanning electron microscope (SEM) images at two different magnifications of the porous poly(3-hydroxybutyrate) membrane produced in Example 14 according to embodiments disclosed herein.

[0066] [Figure 4] 10 is a graph of the differential scanning calorimetry (DSC) analysis of the cast P3HB film and the resulting biaxially stretched P3HB membrane described in Example 14 according to embodiments disclosed herein.

[0067] [Figure 5] 1A and 1B are scanning electron microscope (SEM) images at two different magnifications of the porous poly(3-hydroxybutyrate) membrane produced in Example 15 according to embodiments disclosed herein.

[0068] [Figure 6] 1A and 1B are scanning electron microscope (SEM) images at two different magnifications of the porous poly(3-hydroxybutyrate) membrane produced in Example 16 according to embodiments disclosed herein.

[0069] [Figure 7]1A and 1B are scanning electron microscope (SEM) images at two different magnifications of the porous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) membrane described in Example 17 according to embodiments disclosed herein.

[0070] [Figure 8] 1 is a graph of differential scanning calorimetry (DSC) analysis of the cast PHBV film and the resulting biaxially stretched PHBV membrane described in Example 17 according to embodiments disclosed herein.

[0071] [Figure 9] 1 is a scanning electron microscope (SEM) image of a porous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) membrane described in Example 19 according to embodiments disclosed herein.

[0072] [Figure 10] 1 is a scanning electron microscope (SEM) image of the porous poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) membrane described in Example 20 according to embodiments disclosed herein.

[0073] [Figure 11] 1A and 1B are scanning electron microscope (SEM) images of a porous poly(3-hydroxybutyrate) / polyethylene composite membrane described in Example 22 according to embodiments disclosed herein. A is a top view of the composite showing the porous P3HB layer with a node and fibril microstructure. B is a cross-sectional view of the porous P3HB / PE composite showing the porous P3HB layer and the porous polyethylene layer. DETAILED DESCRIPTION OF THE INVENTION

[0074] Definitions and Nomenclature The present disclosure is not intended to be limiting. For example, the terminology used in this application should be interpreted broadly in the context of the meaning that one skilled in the art would give to the terminology. It should be understood that the terms "melting temperature," "melting temperature," and "melting point" may be used interchangeably herein.

[0075] With regard to terminology that includes imprecision, the terms "about" and "approximately" may be used interchangeably to refer to measurements that include the stated measurement as well as measurements that are reasonably close to the stated measurement. A measurement that is reasonably close to the stated measurement deviates reasonably slightly from the stated measurement to an extent that is understood and easily identified by one of ordinary skill in the art. Such deviations may result from, for example, measurement error, differences in calibration of measuring and / or manufacturing equipment, human error in reading and / or setting measurements, minor adjustments made to optimize performance and / or structural parameters to account for differences in measurements associated with other components, specific implementation scenarios, imprecise adjustment and / or manipulation of objects by humans or machines, etc. If it is determined that a person of ordinary skill in the art would not be able to easily identify such a reasonably small difference, the terms "about" and "approximately" may be understood to mean ±10% of the stated value.

[0076] "Polyhydroxyalkanoates (PHAs)," as used herein, are linear biodegradable polyesters that can be produced by a variety of microorganisms and synthesized chemically (Westlie et al., supra).

[0077] In some embodiments, PHA polymers suitable for preparing the present porous articles include those shown in Formula I and Formula II: Formula I [ka] or Formula II: [ka] [In the formula, R1 and R2 are independently H, or C1-C6 alkyl, or aryl; R3 is C1-C7 alkyl or aryl; X is 2 to 4; n = 3000–100,000].

[0078] In some embodiments, R1 and R2 are both hydrogen. In some embodiments, at least one of R1 and R2 is C1-C6 alkyl or aryl. In some embodiments, R1 and R2 are both C1-C6 alkyl or aryl. In some embodiments, R1 and R2 are both C1-C6 alkyl.

[0079] The PHA polymer used to prepare the present microporous PHA articles having a fibrillated microstructure (i.e., nodes interconnected by fibrils, or substantially only fibrils) can be a PHA homopolymer, a PHA copolymer, or a PHA terpolymer.

[0080] PHAs are classified based on the number of carbon atoms in their monomer units. Some short-chain PHAs, consisting of monomers with 3 to 5 carbon atoms, include poly(3-hydroxybutyrate), poly(3-hydroxybutyrate-co-3-hydroxyvalerate), poly(4-hydroxybutyrate), and poly(3-hydroxybutyrate-co-4-hydroxybutyrate). Medium-chain PHAs, consisting of monomers with 6 to 14 carbon atoms, include poly(3-hydroxybutyrate-co-3-hydroxyhexanoate), poly(3-hydroxybutyrate-co-3-hydroxyoctanoate), and poly(3-hydroxybutyrate-co-3-hydroxydecanoate). Meanwhile, long-chain PHAs are composed of monomers with at least 15 carbon atoms (Tan et al., Polymers 2014, 6: 706-754).

[0081] PHAs can contain mono- or di-substituted alkyl or aryl groups on the alpha hydrogen of the PHA monomer, which enhances the thermal stability of the resulting PHA polymer by suppressing cis-elimination (Zhou et al., Science 380, 64-69 (2023)). Examples of such substituted PHA polymers include, but are not limited to, poly(3-hydroxy-2,2-dimethylbutyrate) (PH(Me)B) and poly(3-hydroxy-2,2-diethylbutyrate) (PH(Et)B).

[0082] Many linear PHA homopolymers and copolymers are semi-crystalline. Relative crystallinity can be measured using a variety of well-known techniques, including, but not limited to, densitometry, differential scanning calorimetry, X-ray diffraction, infrared spectroscopy, and nuclear magnetic resonance (NMR).

[0083] The method produces a node and fibril microstructure in which the fibrils contain extended molecular chains of the PHA polymer oriented along the longitudinal axis of the fibril. The oriented chains may be in the form of extended chain crystals (ECC). "Extended chain crystals," as used herein, refer to a crystalline morphology in which linear PHA polymer chains are oriented in a highly extended conformation. Extended chain crystals are the thermodynamically most stable form of polymeric materials. Thus, extended chain crystals of PHA polymers have a melting temperature higher than the melting temperature of the PHA polymer before stretching. The presence of extended chain crystals can be determined using differential scanning calorimetry (DSC).

[0084] "Partially crystalline," as used herein, refers to a semi-crystalline polymer having a crystallinity ranging from about 5% to less than 90%.

[0085] Examples of various PHAs and their associated melting and glass transition temperatures are provided in Table 1 below. [Table 1] Description of Various Embodiments

[0086] The present disclosure relates to PHA-based microporous and tough articles with node and fibril structures and methods for producing such articles using a below-melt processing approach. The PHA-based microporous articles processed using a below-melt processing approach exhibit improved processability and mechanical properties and help maintain PHA polymers as a bio-based and sustainable material of choice.

[0087] In some embodiments, PHA-based microporous intermediates can be produced by solvent-induced phase inversion and thermally-induced phase inversion, both processes carried out below the melting temperature of the selected PHA. The intermediates can be produced by blending or dissolving untreated PHA homopolymers and / or copolymers with solvents and / or plasticizers.

[0088] In some embodiments, the intermediate can then be stretched or drawn at a temperature above the glass transition temperature and below the melting temperature of the selected PHA. Stretching can be uniaxial, biaxial, and / or continuous. The final stretched article has a node and fibril microstructure in which the fibrils contain molecular chains oriented along their longitudinal axes, resulting in improved mechanical properties. PHAs are surface-degrading materials. The degradation rate of the final article can also be controlled through its properties by varying the processing parameters of the stretching and / or the initial properties of the PHA. For example, the degradation rate can be controlled by the surface area, molecular weight, crystallinity, etc. of the PHA.

[0089] In some embodiments, a method for forming a porous expanded PHA composite includes depositing a partially crystallized PHA polymer onto a substrate at a deposition temperature below the melting temperature of the PHA polymer to form a PHA-substrate composite. Depositing the PHA polymer can include dissolving the PHA polymer in a solvent to form a PHA solution, casting the PHA solution onto the substrate, and at least partially crystallizing the PHA polymer by partially removing the solvent, adjusting the deposition temperature, or a combination thereof.

[0090] In some embodiments, the method can also include stretching the PHA-substrate composite at a temperature between the glass transition temperature of the PHA polymer and the melting temperature of the PHA polymer. The formed PHA composite can include a porous PHA material having a microstructure, the microstructure including a plurality of nodes and a plurality of fibrils interconnecting the plurality of nodes, the fibrils defining a fibril axis. The fibrils of the porous expanded PHA composite can include extended chain crystals (ECC) of the PHA polymer oriented along the fibril axis. The extended chain crystals of the PHA polymer can have a melting temperature higher than the melting temperature of the PHA polymer prior to stretching. The PHA composite can be stretched uniaxially, biaxially, or radially.

[0091] Semicrystalline PHA polymers can include combinations of short-, medium-, and long-chain PHA monomers, homopolymers, or copolymers. In some embodiments, PHA polymers can include monomers, homopolymers, or copolymers containing 3-hydroxybutyrate, 3-hydroxyvalerate, 4-hydroxybutyrate, 3-hydroxyhexanoate, or any combination thereof. In some embodiments, PHA copolymers can include monomers such as 3-hydroxyhexanoate, 3-hydroxyoctanoate, 3-hydroxydecanoate, and combinations thereof. In some embodiments, the PHA polymer can include poly(3-hydroxybutyrate) (PHB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly(4-hydroxybutyrate) (P4HB), poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB4HB), or poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) P(3HB-co-3HHx). In some embodiments, the PHA polymer can be poly(3-hydroxybutyrate-co-3-hydroxyoctanoate) or poly(3-hydroxybutyrate-co-3-hydroxydecanoate).

[0092] In some embodiments, the PHA polymer can include at least one porogen prior to deposition onto the substrate. In some cases, the porogen can be removed prior to stretching the PHA-substrate composite. In some cases, the porogen can be removed after stretching the PHA-substrate composite.

[0093] The substrate may be deformable. In some embodiments, the substrate may be an expandable polymer different from the PHA polymer. In some embodiments, the substrate may comprise a member selected from polytetrafluoroethylene (PTFE) tape, PTFE film, polyolefin tape, polyolefin film, expanded polyolefin film, ultra-high molecular weight polyethylene (UHMWPE) tape, UHMWPE film, and expanded UHMWPE film.

[0094] The step of stretching the PHA-substrate composite can be carried out at a temperature about 5°C to 15°C below the melting temperature of the PHA polymer, or about 6°C to 14°C below the melting temperature of the PHA polymer, or about 7°C to 13°C below the melting temperature of the PHA polymer, or about 8°C to 12°C below the melting temperature of the PHA polymer, or about 9°C to 11°C below the melting temperature of the PHA polymer, or any temperature within the aforementioned ranges. In some embodiments, the PHA-substrate composite can be stretched at a temperature about 10°C below the melting temperature of the PHA polymer.

[0095] The stretching of the PHA substrate is performed at a rate of about 1% / s to about 1000% / s, or about 2% / s to about 950% / s, or about 3% / s to about 900% / s, or about 4% / s to about 850% / s, or about 5% / s to about 800% / s, or about 6% / s to about 750% / s, or about 7% / s to about 700% / s, or about 8% / s to about 650% / s, or about 9% / s to about 600% / s, or about 10% / s to about 550% / s. % / s, or from about 15% / s to about 500% / s, or from about 20% / s to about 450% / s, or from about 25% / s to about 400% / s, or from about 30% / s to about 350% / s, or from about 35% / s to about 300% / s, or from about 40% / s to about 250% / s, or from about 45% / s to about 200% / s, or from about 50% / s to about 150% / s, or any rate within the aforementioned ranges.

[0096] The PHA-substrate complex may have a ratio of about 1:1.1 to about 1:100, or about 1:1.2 to about 1:95, or about 1:1.3 to about 1:90, or about 1:1.4 to about 1:85, or about 1:1.5 to about 1:80, or about 1:1.6 to about 1:75, or about 1:1.7 to about 1:70, or about 1:1.8 to about 1:65, or about 1:1.9 to about 1:60, or about The stretch ratio may be from 1:2 to about 1:55, or from about 1:3 to about 1:50, or from about 1:4 to about 1:45, or from about 1:5 to about 1:40, or from about 1:6 to about 1:35, or from about 1:7 to about 1:30, or from about 1:8 to about 1:25, or from about 1:9 to about 1:20, or from about 1:10 to about 1:15, or any stretch ratio within the aforementioned ranges.

[0097] In some embodiments, the method of forming a porous expanded PHA composite can further include separating the porous PHA material from the porous expanded PHA composite to form a self-supporting porous PHA material, which can be in the form of a membrane, a tube, a sheet, or a three-dimensional shape.

[0098] The self-supporting porous PHA material can have a porosity of about 25% to about 99%, or about 30% to about 98.5%, or about 35% to about 98%, or about 40% to about 97.5%, or about 45% to about 97%, or about 50% to about 96.5%, or about 55% to about 96%, or about 60% to about 95.5%, or about 65% to about 95%, or about 66% to about 94.5%, or about 67% to about 94%, or any porosity within the aforementioned ranges.

[0099] The self-supporting porous PHA material can have a matrix tensile strength in the machine direction (MD) and / or transverse direction (TD) of at least 5 MPa. In some embodiments, the self-supporting porous PHA material can have a matrix tensile strength in the MD or TD of at least 10 MPa, or at least 15 MPa, or at least 20 MPa, or at least 25 MPa.

[0100] In some embodiments, the total surface area per unit mass (specific surface area) of the self-supporting porous PHA material is about 1 m 2 / g~about 150m 2 / g, or approximately 1 m 2 / g~about 100m 2 / g, or approximately 5m 2 / g ~ approx. 95m 2 / g, or approximately 10 m 2 / g~about 90m 2 / g, or approximately 15m 2 / g~about 85m 2 / g, or approximately 20m 2 / g~about 80m 2 / g, or approximately 25m 2 / g ~ approx. 75m 2 / g, or approximately 26m 2 / g ~ approx. 74m 2 / g, or approximately 27m 2 / g ~ approx. 73m 2 / g, or any specific surface area encompassed within the aforementioned range.

[0101] In some embodiments, the method of forming a porous expanded PHA composite can further include treating the porous expanded PHA composite or the self-supporting porous PHA material to form a modified PHA article. The treatment can include coating, imbibing, laminating, or any combination thereof. In some examples, the modified PHA article can be porous. In some examples, the modified PHA article can be non-porous.

[0102] In some embodiments, a porous expanded PHA composite, a porous self-supporting porous PHA material, or a modified PHA article can be densified to form a densified PHA material. Densification can include the application of heat, pressure, stretching, or any combination thereof. The densified PHA material can include a detectable endotherm associated with the presence of extended chain crystals in the PHA polymer.

[0103] In some embodiments, a porous polyhydroxyalkanoate (PHA) material having a plurality of nodes and a plurality of fibrils interconnecting the plurality of nodes can be formed from a PHA polymer. The plurality of fibrils can define a fibril axis and can include a plurality of extended-chain crystals of the PHA polymer oriented along the fibril axis. Prior to stretching the PHA polymer, the extended-chain crystals of the PHA polymer can have a melting temperature higher than the melting temperature of the PHA polymer. The porous PHA material can be in the form of a membrane, tube, sheet, monofilament, or three-dimensional shape.

[0104] The PHA polymer can comprise a monomer, homopolymer, or copolymer comprising 3-hydroxybutyrate, 3-hydroxyvalerate, 4-hydroxybutyrate, 3-hydroxyhexanoate, or any combination thereof. In some embodiments, the PHA polymer can comprise poly(3-hydroxybutyrate) (PHB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly(4-hydroxybutyrate) (P4HB), poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB4HB), or poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) P(3HB-co-3HHx).

[0105] The PHA polymer has a molecular weight of about 30,000 g / mol to about 10,000,000 g / mol, or about 30,000 g / mol to about 10,000,000 g / mol, or about 40,000 g / mol to about 9,000,000 g / mol, or about 50,000 g / mol to about 8,000,000 g / mol, or about 60,000 g / mol to about 7,000,000 g / mol, or about 70,000 g / mol to about 6,000,000 g / mol, or about 80,000 g / mol. The polymer may have a molecular weight of from about 1 to about 5,000,000 g / mol, or from about 90,000 g / mol to about 4,000,000 g / mol, or from about 100,000 g / mol to about 3,000,000 g / mol, or from about 110,000 g / mol to about 2,000,000 g / mol, or from about 120,000 g / mol to about 1,000,000 g / mol, or from about 130,000 g / mol to about 900,000 g / mol, or any molecular weight within the aforementioned ranges.

[0106] In some embodiments, the PHA polymer can be blended with an additional polymer selected from polylactic acid (PLA), polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), cellulose, polyglycolic acid (PGA), polycaprolactone (PCL), polyvinyl acetate (PVAc), chitin, chitosan, starch, and any combination thereof.

[0107] In some embodiments, the porous PHA material can have a porosity of about 25% to about 99%, or about 30% to about 98.5%, or about 35% to about 98%, or about 40% to about 97.5%, or about 45% to about 97%, or about 50% to about 96.5%, or about 55% to about 96%, or about 60% to about 95.5%, or about 65% to about 95%, or about 66% to about 94.5%, or about 67% to about 94%, or any porosity within the aforementioned ranges.

[0108] In some embodiments, the porous PHA material can have a matrix tensile strength in the machine direction (MD) and / or transverse direction (TD) of at least 5 MPa. In some embodiments, the self-supporting porous PHA material can have a matrix tensile strength in the MD or TD of at least 10 MPa, or at least 15 MPa, or at least 20 MPa, or at least 25 MPa.

[0109] In some embodiments, the porous PHA material is about 1 m 2 / g~about 150m 2 / g, or approximately 1 m 2 / g~about 100m 2 / g, or approximately 5m 2 / g ~ approx. 95m 2 / g, or approximately 10 m 2 / g~about 90m 2 / g, or approximately 15m 2 / g~about 85m 2 / g, or approximately 20m 2 / g~about 80m 2 / g, or approximately 25m 2 / g ~ approx. 75m 2 / g, or approximately 26m 2 / g ~ approx. 74m 2 / g, or approximately 27m 2 / g ~ approx. 73m 2 / g. In one exemplary embodiment, the porous PHA material has a total surface area per unit mass (specific surface area) of about 20 m 2 / g or any specific surface area encompassed within the aforementioned range.

[0110] In some embodiments, the porous PHA material has a density of about 0.1 g / m 2 ~about 100g / m 2 , or approximately 0.1 g / m 2 ~about 50g / m 2 , or approximately 0.5 g / m 2 ~about 50g / m 2 , or approximately 0.5 g / m 2 ~about 10g / m2 , or approximately 0.7 g / m 2 ~approx. 9g / m 2 , approximately 0.9 g / m 2 ~about 8g / m 2 , about 1g / m 2 ~about 7g / m 2 , about 1.1g / m 2 ~about 6g / m 2 , about 1.2g / m 2 ~about 5g / m 2 , about 1.5g / m 2 ~about 4.5g / m 2 or any mass per area encompassed within the aforementioned range.

[0111] In some embodiments, the porous PHA material may be in the form of a film having a thickness of about 5 μm to about 500 μm, or about 5 μm to about 100 μm, or about 6 μm to about 90 μm, about 7 μm to about 80 μm, about 8 μm to about 70 μm, about 9 μm to about 65 μm, about 10 μm to about 60 μm, about 11 μm to about 55 μm, or any thickness within the aforementioned ranges.

[0112] In some embodiments, the porous PHA material can have an ATEQ air flow rate of from about 0.1 L / hr to about 1000 L / hr, or from about 0.1 L / hr to about 400 L / hr, or from about 0.5 L / hr to about 390 L / hr, or from about 1 L / hr to about 380 L / hr, or from about 1.5 L / hr to about 370 L / hr, or from about 2 L / hr to about 360 L / hr, or from about 2.5 L / hr to about 350 L / hr, or from about 2.9 L / hr to about 340 L / hr, or from about 3 L / hr to about 330 L / hr, or any ATEQ air flow rate subsumed within the aforementioned ranges.

[0113] In some embodiments, the porous PHA material can have a water entry pressure (WEP) of about 7 kPa.

[0114] In some embodiments, a composite can include the porous PHA material described herein. The composite can be microporous. In some embodiments, an article can include a porous PHA material or a composite including a porous PHA material. The article can include a woven or nonwoven support substrate.

[0115] In some embodiments, materials comprising densified expanded polyhydroxyalkanoates having a detectable endotherm associated with the presence of residual extended chain crystals of the PHA polymer can have a porosity of less than 10%.

[0116] In some embodiments, the PHA-based microporous article having a fibrillated microstructure is in the form of a microporous monofilament. The monofilament can be used to manufacture woven and knitted textile articles, fabrics, medical sutures, fishing line, dental floss / tape, and the like. The PHA monofilament can include various further modifications (e.g., twisting, folding, knotting, embossing, ribbing, adding abrasive fillers, and combinations thereof) to introduce additional texture or roughness, particularly for applications such as medical sutures and dental floss / tape. In one embodiment, the PHA monofilament can be formed by cutting / slitting a PHA film into thin strips of a size appropriate for the desired application using the general methodology described in WO 2022 / 103783 by Minor, R. (which describes the manufacture of porous ultra-high molecular weight polyethylene (UHMWPE) dental floss). In various aspects, the PHA strips can be laminated and subjected to further mechanical modification, such as twisting, folding, knotting, embossing, calendering, additional stretching or drawing, and various combinations thereof, to achieve properties desired for the intended application. In some embodiments, these further mechanical modification steps can be performed at temperatures above or below the melting temperature of the PHA polymer. In further embodiments, the further mechanical modification is performed at a temperature below the melting temperature of the PHA polymer.

[0117] In some embodiments, the porous PHA monofilament further comprises functional additives such as particulate fillers, flavorings, caries prevention agents, colorants, coatings (wax, silicone, etc.), radiopaque materials, etc. The introduction of structural features and functional additives / coatings for dental floss / tape applications into the present PHA monofilaments having a fibrillated microstructure can follow common methodologies used in the manufacture of non-PHA polymer-based dental floss / tapes (see, e.g., U.S. Patent Application Publication No. 2011 / 0214683 by Hardesty and U.S. Patent No. 8,522,796 by Ochs; U.S. Patent No. 7,854,235 by Blanchard et al.; U.S. Patent No. 8,048,111 by Lutz et al.; U.S. Patent No. 7,174,903 by Longoni, E.; U.S. Patent No. 7,060,354 by Baillie et al.; and U.S. Patent No. 6,289,904 by Suhonen et al.).

[0118] In a further embodiment, the porous PHA monofilament is used to manufacture a textile. The textile can include one or more porous PHA monofilament yarns, porous PHA multifilament yarns, or a combination thereof. Such yarns can be formed from the microporous PHA monofilaments described above, as well as other materials such as wool, cotton, silk, flax, hemp, various animal hairs, angora, sisal, ramie, acrylic, polyester, polyamide, polyaramid, polyurethane, acetate, rayon, polybenzimidazole, polybenzoxazole, lyocell, modacrylic, polyvinylidene chloride, carbon, glass, cellulose, cellulose acetate, cellulose ester, elastic fibers, or any combination thereof. Test Method Average thickness measurement

[0119] Thickness was measured by placing the sample between the two plates of a Mitutoyo contact thickness gauge (Mitutoyo America Corporation, Aurora, Illinois). The average of three measurements was reported and used in the porosity calculation below. Porosity calculation

[0120] The porosity of the membrane was calculated as 1.2 g / cm3 as the total density of the sample. 3 The density of the sample was calculated using the following formula: The samples were die cut using a 25 mm circular die. Each sample was weighed on an electronic balance (Mettler Toledo, Columbus, Ohio). The density of the sample was calculated using the following formula:

number

[0121] The average of three measurements was reported. Differential Scanning Calorimetry (DSC)

[0122] DSC data were collected using a TA Instruments Discovery DSC (TA Instruments-Waters LLC, New Castle, DE) from -50 °C to 200 °C using a heating rate of 10 °C / min. Membrane samples were prepared by punching out 4 mm disks, placing them in a pan, and crimping the lid to sandwich the membrane disk between the pan and lid. Scanning electron microscope (SEM)

[0123] SEM samples were imaged using a Hitachi FlexSEM 1000 II (Hitachi High-Tech America, Inc., Schaumburg, IL) at 1.0–10 kV. Tensile test

[0124] Matrix tensile strength (MTS) was evaluated by measuring the stress response to a constant uniaxial displacement rate using an axial test on a dynamic mechanical analyzer (DMA) (model: RSA-G2, manufactured by TA Instruments - Waters LLC, New Castle, Delaware, USA). Rectangular specimens of the samples were die-cut with a width of 4.7 mm. The DMA was equipped with a film / fiber tensile clamp. The clamp gap was referenced to the same test conditions at room temperature (approximately 22 °C). The prepared specimens were mounted in the DMA clamp with a gauge length of 10 mm. The axial test consisted of measuring the transient axial load while applying a constant displacement rate of 0.1 mm / s.

[0125] The matrix tensile strength was calculated using the following formula: MTS = (maximum stress / cross-sectional area) x (true density / bulk density of sample). Air flow measurement

[0126] ATEQ® Airflow is a test method for measuring the volumetric flow rate of air through a sample. Each sample is clamped between two plates, each fitted with a No. 210 or equivalent O-ring, and a 2.99 cm diameter pipe across the flow path. 2 Through-holes were drilled between the O-rings to create a sealed area. The downstream flow-path hole had a grid-like support structure across it. The air flow rate (L / hr) through each sample was measured using an ATEQ® (ATEQ Corp., Livonia, Michigan) Premier D Compact Flow Tester or equivalent by subjecting each sample to an air pressure differential of 1.2 kPa (12 mbar) across the sample. Reported results are the average of three measurements. Specific surface area measurement

[0127] The specific surface area of ​​the samples was measured by using Brunauer-Emmett-Teller (BET) surface area analysis with a Quantachrome NOVAtouch LX4 (Anton Paar GmbH, Germany). Water entry pressure (WEP) measurement

[0128] Water intrusion pressure provides a test method for water intrusion through a membrane. The test sample is sandwiched between a pair of test plates. The bottom plate allows a portion of the sample to be pressurized with water. A strip of pH paper is placed on the sample between the non-pressurized plates as an indicator of evidence of water intrusion. Pressure is then applied to the sample in small increments, waiting 10 seconds after each pressure change, until a color change in the pH paper indicates early signs of water intrusion. The water pressure at the time of intrusion or intrusion is recorded as the water intrusion pressure. Test results are taken from the center of the test sample to avoid erroneous results that can result from damaged edges. Weight average molecular weight by size exclusion chromatography (SEC)

[0129] Weight-average molecular weights were measured on a Malvern OMNISEC Reveal multi-detector SEC (Malvern PANanalytical, Westborough, MA) equipped with Shodex (Showa Denko America, Inc., New York, NY) columns KF-806L, KF807L, and KF-803, using chloroform (Sigma-Aldrich, St. Louis, MO; GPC grade) solvent at a flow rate of 0.8 mL / min, an injection volume of 100 μL, and a concentration of 2–3 mg / mL at 30°C. Example Example 1: Preparation of Poly(3-hydroxybutyrate) (P3HB) Solution

[0130] Ten grams of P3HB polymer (Biomer, Bavaria, Germany) was dried under vacuum at room temperature (approximately 22°C) for 24 hours. The average molecular weight of the polymer was measured to be 1400 kDa. The P3HB polymer was then dissolved in 100 mL of chloroform (Sigma Aldrich, St. Louis, MO) under reflux conditions at 75°C for 1 hour in a jacketed glass reactor equipped with a polytetrafluoroethylene (PTFE) stirrer blade. The resulting solution was aged at room temperature (approximately 22°C) for 24 hours. Example 2: Preparation of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) Solution

[0131] Ten grams of PHBV polymer (TianAn Biologic Materials Co., Ltd., Zhejiang, China) containing 3 mol% modification (i.e., 3 mol% 3-hydroxyvalerate) was dried under vacuum at room temperature (approximately 22°C) for 24 hours. The average molecular weight of the polymer was 400 kDa according to the supplier. The PHBV polymer was then dissolved in 100 mL of chloroform (Sigma Aldrich) at 65°C for 1 hour under reflux conditions in a jacketed glass reactor equipped with a PTFE stirring blade. The resulting solution was aged at room temperature (approximately 22°C) for 24 hours. Example 3: Preparation of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P3HB / PHBH) solution

[0132] One gram of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) polymer (Sigma-Aldrich) with 15.2 mol% modification (15.2 mol% 3-hydroxyhexanoate) and a supplier-provided average molecular weight of 580 kDa and 9 g of poly(3-hydroxybutyrate) (Biomer, Bavaria, Germany) were dissolved together in 100 mL of chloroform under reflux conditions at 75°C for 1 hour in a jacketed glass reactor equipped with a PTFE stirrer blade. The resulting solution was aged at room temperature (approximately 22°C) for 24 hours. Example 4: Preparation of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) / polyethylene glycol (PEG) solution

[0133] 2.4 grams of polyethylene glycol polymer (Sigma Aldrich) with a supplier average molecular weight of 8 kDa was added to the 10% w / v PHBV solution prepared in Example 2 and allowed to dissolve for 24 hours at room temperature (approximately 22° C.) with magnetic stirring. The ratio of PHBV weight to PEG weight was 5:1 in the final solution. Example 5: Preparation of Poly(3-hydroxybutyrate) Cast Tapes on Polytetrafluoroethylene (PTFE) Substrates Using Methanol for Non-Solvent-Induced Phase Separation (NIPS)

[0134] Porous PTFE tape (258 μm thick, 28% porosity) was fabricated according to the methodology of U.S. Patent No. 3,953,566 to Gore. The porous PTFE tape was attached to a glass plate and then coated with the P3HB solution (15 mL) prepared in Example 1 using a 254 μm drawdown bar. The P3HB-coated PTFE tape was then immediately transferred to a bath filled with methanol (VWR International, LLC, Radnor, PA) at room temperature (approximately 22°C) for non-solvent-induced phase separation. The P3HB-coated PTFE tape was kept in the methanol bath for at least 5 minutes until solvent exchange was complete. The solvent-exchanged P3HB / PTFE tape was removed from the bath and air-dried at room temperature (approximately 22°C) for 24 hours to remove excess solvent. Example 6: Preparation of Poly(3-hydroxybutyrate) Cast Tapes on Polyethylene (PE) Substrates Using Methanol for Nonsolvent-Induced Phase Separation

[0135] A porous ultra-high molecular weight polyethylene (PE) tape (manufactured according to U.S. Pat. No. 10,577,468 to Sbriglia) with a thickness of 185 μm and a porosity of 25% was coated with 10 mL of the P3HB solution prepared in Example 1 using a 254 μm drawdown bar. The P3HB-coated PE tape was immediately immersed in a bath filled with methanol (VWR International, LLC) at room temperature (approximately 22° C.) for non-solvent-induced phase separation. The P3HB-coated PE tape was kept in the methanol bath for 5 minutes until the solvent exchange was complete. The solvent-exchanged P3HB / PE tape was removed from the bath and air-dried at room temperature (approximately 22° C.) for 24 hours to remove excess solvent. Example 7: Preparation of Poly(3-hydroxybutyrate) Cast Tapes on Polyethylene (PE) Substrates Using Methanol for Nonsolvent-Induced Phase Separation

[0136] The P3HB solution prepared in Example 1 was used to coat a porous ultra-high molecular weight polyethylene (UHMWPE) tape (manufactured according to U.S. Pat. No. 10,577,468 to Sbriglia) with a thickness of 360 μm and a porosity of 26% using a 254 μm drawdown bar. The P3HB-coated PE tape was immediately immersed in a bath filled with methanol (VWR International, LLC) at room temperature (approximately 22° C.) for non-solvent-induced phase separation. The P3HB-coated PE tape was kept in the methanol bath for 5 minutes until solvent exchange was complete. The solvent-exchanged P3HB / PE tape was removed from the bath and air-dried at room temperature (approximately 22° C.) for 24 hours to remove excess solvent. Example 8: Preparation of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) Cast Tapes on Polyethylene (PE) Substrates Using Isopropanol for Non-Solvent-Induced Phase Separation

[0137] A porous ultra-high molecular weight polyethylene (UHMWPE) tape (manufactured according to U.S. Pat. No. 10,577,468 to Sbriglia) with a thickness of 185 μm and a porosity of 25% was coated with 15 mL of the PHBV solution prepared in Example 2 using a 254 μm thick drawdown bar. The PHBV-coated PE tape was immediately immersed in a bath filled with isopropyl alcohol (VWR International, LLC) at room temperature (approximately 22° C.). The solvent-exchanged PHBV / PE tape was kept in the isopropyl alcohol bath for 5 minutes to ensure solvent exchange. The solvent-exchanged PHBV / PE tape was removed from the bath and air-dried at room temperature (approximately 22° C.) for 24 hours to remove excess solvent. Example 9: Preparation of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) / polyethylene glycol (PEG) cast tapes on polyethylene substrates

[0138] The PHBV / PEG solution prepared in Example 4 was used to coat a porous ultra-high molecular weight polyethylene (UHMWPE) tape (manufactured according to U.S. Pat. No. 10,577,468 to Sbriglia) having a thickness of 185 μm and a porosity of 25% using a 254 μm drawdown bar. The PHBV / PEG-coated PE tape was air-dried at room temperature (approximately 22° C.) for 24 hours to remove the chloroform solvent. The dried PHBV / PEG-coated PE tape was immersed in a reverse osmosis water bath at room temperature (approximately 22° C.) for 24 hours to remove the PEG. The PHBV-coated PE tape was then dried under vacuum at room temperature (approximately 22° C.) for 24 hours. Example 10: Preparation of Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P3HB / PHBH) Cast Tapes on Polyethylene Substrates Using Methanol for Nonsolvent-Induced Phase Separation

[0139] A porous ultra-high molecular weight polyethylene (UHMWPE) tape (manufactured according to U.S. Pat. No. 10,577,468 to Sbriglia) with a thickness of 185 μm and a porosity of 25% was coated with the P3HB / PHBH solution blend prepared in Example 3 using a 254 μm thick drawdown bar. The P3HB / PHBH-coated PE tape was immediately immersed in a bath filled with methanol (VWR International, LLC) at room temperature (approximately 22° C.) for 10 minutes to ensure solvent exchange. The solvent-exchanged P3HB / PHBH-coated PE tape was removed from the methanol bath and air-dried at room temperature (approximately 22° C.) for 24 hours to remove excess solvent. Example 11: Preparation of uniaxially stretched poly(3-hydroxybutyrate) membrane

[0140] The P3HB / PTFE tape prepared according to Example 5 was used as the starting material for the preparation of uniaxially stretched P3HB membranes. Rectangular specimens (120 mm long, 10 mm wide) were cut from the P3HB / PTFE tape with a razor blade and clamped between two pneumatic clamps with a gauge length of 80 mm (INSTRON® Model 5965 Tensile Tester with Built-in Convection Oven, Illinois Tool Works Inc., Norwood, Massachusetts). The specimens were equilibrated at 110°C for 1 minute and then uniaxially stretched at a rate of 100% / s to four times their original length. The uniaxially stretched P3HB membranes exhibited a porous node and fibril microstructure (see Figures 1A and 1B). The properties of the uniaxially stretched P3HB membranes are listed in Table 2. Example 12: Preparation of uniaxially stretched poly(3-hydroxybutyrate) membrane

[0141] The P3HB / PE tape prepared according to Example 6 was used as the starting material. Rectangular specimens (70 mm wide, 150 mm long) were cut from the P3HB / PE tape. The rectangular specimens were loaded into a Karo IV biaxial stretching machine (Brueckner Maschinenbau GmbH & Co., Siegsdorf, Germany) and thermally equilibrated at 120°C for 2 minutes. The rectangular specimens were then uniaxially stretched to 9 times their original length at a strain rate of 100% / s. SEM micrographs of the uniaxially stretched specimens show the formation of porous P3HB membranes with node and fibril microstructures (see Figures 2A and 2B). The properties of the uniaxially stretched P3HB membranes are shown in Table 2. Example 13: Preparation of biaxially stretched poly(3-hydroxybutyrate) membrane

[0142] Poly(3-hydroxybutyrate)-coated polyethylene tape (P3HB / PE) was prepared according to Example 6. Rectangular specimens (70 mm wide (transverse direction; TD) and 150 mm long (machine direction; MD)) were cut from the P3HB / PE tape. The rectangular specimens were loaded into a Karo IV biaxial stretching machine (Brueckner Maschinenbau GmbH & Co.) and thermally equilibrated at 120°C for 2 minutes. After equilibrating at 120°C for 2 minutes, the rectangular specimens were biaxially stretched (simultaneously in MD and TD) at a strain of 100% / s in both directions (MD and TD) until a total area ratio of 8 was reached. The biaxially stretched P3HB film was removed from the PE substrate. The specific surface area of ​​the P3HB film was measured to be 72.03 m. 2 Further properties of the biaxially stretched P3HB membrane are shown in Table 2. Example 14: Preparation of biaxially stretched poly(3-hydroxybutyrate) membrane

[0143] Poly(3-hydroxybutyrate)-coated polyethylene tape (P3HB / PE) was prepared according to Example 6. Rectangular specimens measuring 70 mm in width (transverse direction; TD) and 150 mm in length (machine direction; MD) were cut from the P3HB / PE tape. The rectangular specimens were loaded into a Karo IV biaxial stretching machine (Brueckner Maschinenbau GmbH & Co.) and thermally equilibrated at 120°C for 2 minutes. The rectangular specimens were simultaneously biaxially stretched in both MD and TD at a strain rate of 100% / s until an area ratio of 12 was reached. The biaxially stretched P3HB membrane was removed from the PE substrate. SEM micrographs of the biaxially stretched membrane showed a porous node and fibril microstructure (see Figures 3A and 3B). Differential scanning calorimetry (DSC) analysis was performed on the P3HB cast film (before biaxial stretching) and the biaxially stretched P3HB membrane (Figure 4). As shown in Figure 4, the biaxially stretched P3HB membrane has a higher melting peak due to the presence of extended chain crystals within the fibrils. Tensile tests were performed and the matrix tensile strength (MTS) of the porous biaxially stretched P3HB membrane was 28.2 MPa in both the MD and TD directions. The biaxially stretched P3HB membrane was 50 μm thick and had a calculated porosity of 93.6%. Further properties of the biaxially stretched P3HB membrane are listed in Table 2. Example 15: Preparation of biaxially stretched poly(3-hydroxybutyrate) membrane

[0144] Poly(3-hydroxybutyrate)-coated polyethylene tape (P3HB / PE) was prepared according to Example 7. Rectangular specimens measuring 70 mm wide (transverse direction; TD) and 150 mm long (machine direction; MD) were cut from the P3HB / PE tape. The rectangular specimens were loaded into a Karo IV biaxial stretching machine (Brueckner Maschinenbau GmbH & Co.) and thermally equilibrated at 120°C for 2 minutes. The rectangular specimens were simultaneously biaxially stretched in both MD and TD at a strain of 100% / s until an area ratio of 30 was reached. The biaxially stretched P3HB membrane was removed from the PE substrate. The calculated porosity of the biaxially stretched P3HB membrane was 96%. The ATEQ air flow rate through the membrane was measured to be 161 L / hr. SEM micrographs of the simultaneously biaxially stretched P3HB membrane show a porous microstructure containing nodes and fibrils (Figures 5A and 5B). The properties of the biaxially stretched P3HB film are shown in Table 2. Example 16: Preparation of biaxially stretched poly(3-hydroxybutyrate) membrane

[0145] Poly(3-hydroxybutyrate)-coated polyethylene tape (P3HB / PE) was prepared according to Example 6. Rectangular specimens measuring 70 mm in width (transverse direction; TD) and 150 mm in length (machine direction; MD) were cut from the P3HB / PE tape. The rectangular specimens were loaded into a Karo IV biaxial stretching machine (Brueckner Maschinenbau GmbH & Co.) and thermally equilibrated at 140°C for 2 minutes. The rectangular specimens were (simultaneously) biaxially stretched in both MD and TD at a strain of 100% / s until an area ratio of 4 was reached. The biaxially stretched P3HB membrane was removed from the PE substrate. SEM micrographs of the biaxially stretched P3HB membrane reveal a porous microstructure containing nodes and fibrils (Figures 6A and 6B). The properties of the biaxially stretched P3HB membrane are listed in Table 2. Example 17: Preparation of biaxially stretched poly(3-hydroxybutyrate-co-3-hydroxyvalerate) membrane

[0146] Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)-coated polyethylene tape (PHBV / PE) was prepared according to Example 8. Rectangular specimens measuring 70 mm in width (transverse direction; TD) and 150 mm in length (machine direction; MD) were cut from the PHBV / PE tape. The rectangular specimens were loaded into a Karo IV biaxial stretching machine (Brueckner Maschinenbau GmbH & Co.) and thermally equilibrated at 120°C for 2 minutes. The rectangular specimens were biaxially stretched (simultaneously in MD and TD) at strain rates of 100% / s in MD and 10% / s in TD until an area ratio of 16 was reached. The biaxially stretched PHBV membrane was removed from the PE substrate. SEM micrographs of the biaxially stretched PHBV membrane show a porous microstructure containing nodes and fibrils (Figures 7A and 7B). Differential scanning calorimetry (DSC) analysis was performed on the PHBV cast film (before biaxial stretching) and the biaxially stretched PHBV membrane (Figure 8). As shown in Figure 8, the biaxially stretched PHBV membrane has a higher melting peak due to the presence of extended chain crystals within the fibrils. The calculated porosity of the biaxially stretched PHBV membrane was 94%. The ATEQ air flow rate through the membrane was measured to be 321 L / hr. Further properties of the biaxially stretched PHBV membrane are listed in Table 2. Example 18: Preparation of continuous stretched PHBV membrane

[0147] Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)-coated polyethylene tape (PHBV / PE) was prepared according to Example 8. A rectangular specimen measuring 70 mm in width (transverse direction; TD) and 150 mm in length (machine direction; MD) was cut from the PHBV / PE tape. The rectangular specimen was loaded into a Karo IV biaxial stretching machine (Brueckner Maschinenbau GmbH & Co.) and thermally equilibrated at 120°C for 2 minutes. The rectangular specimen was first stretched in the MD to four times its original length at a strain rate of 10% / s, and then subsequently stretched in the TD at 100% / s until the specimen reached a total area ratio of 16. The biaxially stretched PHBV membrane was removed from the PE substrate. The free-standing biaxially stretched PHBV membrane had a thickness of 26 μm and a calculated porosity of 93.8%. The ATEQ air flow rate through the biaxially stretched PHBV membrane was 313 L / hr and the water entry pressure (WEP) was 6.89 kPa. Further properties of the biaxially stretched PHBV membrane are shown in Table 2. Example 19: Preparation of biaxially stretched poly(3-hydroxybutyrate-co-3-hydroxyvalerate) membranes using polyethylene glycol as porogen

[0148] Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) tape was prepared according to Example 9 (the polyethylene glycol porogen had been removed beforehand). Rectangular specimens measuring 70 mm in width (transverse direction; TD) and 150 mm in length (machine direction; MD) were cut from the PHBV tape. The rectangular specimens were loaded into a Karo IV biaxial stretching machine (Brueckner Maschinenbau GmbH & Co.) and thermally equilibrated at 120°C for 2 minutes. The rectangular specimens were simultaneously biaxially stretched in both MD and TD at a strain rate of 100% / s until an area ratio of 4 was reached. The biaxially stretched PHBV membrane was removed from the PE substrate. SEM micrographs of the biaxially stretched PHBV membrane showed a porous structure containing nodes and fibrils (Figure 9). The biaxially stretched PHBV membrane had a thickness of 20 μm and a calculated porosity of 68%. Further properties of the biaxially stretched PHBV membrane are shown in Table 2. Example 20: Preparation of uniaxially stretched P3HB / PHBH membrane

[0149] Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P3HB / PHBH)-coated polyethylene tape was prepared according to Example 10. Rectangular specimens measuring 120 mm in length and 10 mm in width were cut from the P3HB / PHBH tape with a razor blade. The rectangular specimens were clamped between two pneumatic jaws with a gauge length of 80 mm (INSTRON® Model 5965 Tensile Tester with Built-in Convection Oven, Illinois Tool Works Inc., Norwood, MA). The specimens were equilibrated at 120°C for 1 minute and then uniaxially stretched at a rate of 100% / s to 5 times their original length. The uniaxially stretched P3HB / PHBH membrane exhibited a porous microstructure containing nodes and fibrils (Figure 10). Further properties of the uniaxially stretched P3HB / PHBH membrane are listed in Table 2. Example 21: Preparation of densified poly(3-hydroxybutyrate) films from stretched P3HB membranes

[0150] A biaxially stretched P3HB membrane prepared according to Example 14 was layered between two polyimide films (KAPTON®, EI du Pont de Nemours and Company, Wilmington, Delaware) and densified between two silicone rolls set at 120°C. The compression force was set at 400 N / mm at a line speed of 1 meter per minute. The resulting densified article was 12 μm thick and had a mass per unit area (MPA) of 3.67 g / m. 2 The properties of the densified P3HB film are shown in Table 2. Example 22: Preparation of biaxially oriented poly(3-hydroxybutyrate) / polyethylene composite (P3HB / PE)

[0151] Poly(3-hydroxybutyrate) / polyethylene (P3HB / PE) composite tape was prepared according to Example 7. Rectangular specimens measuring 70 mm in width (MD) and 150 mm in length (TD) were cut from the P3HB / PE composite tape. The rectangular specimens were loaded into a Karo IV biaxial stretching machine (Brueckner Maschinenbau GmbH & Co.) and thermally equilibrated at 120°C for 2 minutes. The rectangular specimens were (simultaneously) biaxially stretched in both MD and TD at a strain of 100% / s until an area ratio of 4 was reached. SEM micrographs of the biaxially stretched P3HB / PE composite showed a porous microstructure with nodes and fibrils (Figures 11A and 11B). Figure 11A is a top view of the P3HB / PE composite, showing the node and fibril microstructure of the P3HB layer. Figure 11B is a cross-sectional view showing the microstructure of the layered porous P3HB / PE composite. Comparative Example 23: Preparation of uniaxially stretched high-density poly(3-hydroxybutyrate) film without using a stretchable substrate

[0152] A glass plate was coated with the solution prepared as described in Example 1 using a 254 μm drawdown bar. The P3HB-coated glass was then covered with a glass cover, and the chloroform solvent was allowed to slowly evaporate at room temperature (approximately 22°C) for 24 hours to obtain a high-density P3HB film. A rectangular specimen measuring 120 mm in length and 10 mm in width was cut from the high-density P3HB film with a razor blade and clamped between two pneumatic clamps with an 80 mm gauge length (INSTRON® Model 5965 Tensile Tester with Built-in Convection Oven, Illinois Tool Works Inc., Norwood, Massachusetts). The clamped high-density P3HB film was equilibrated at 100°C for 1 minute and then uniaxially stretched at a rate of 100% / s until a strain of 25% was achieved. Stretching the high-density P3HB film beyond 25% was not possible due to the occurrence of macroscopic defects beyond this strain. This indicates that it is not possible to form a porous P3HB membrane with a node and fibril microstructure. Comparative Example 24: Uniaxial Stretching of High-Density Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Film

[0153] High-density poly(3-hydroxybutyrate-co-3-hydroxyvalerate) film (10 μm thick) was obtained from Goodfellow Corporation (Pittsburgh, PA). The high-density PHBV film was cut into a rectangular shape (120 mm long, 10 mm wide). The rectangular PHBV high-density film sample was clamped between two pneumatic clamps with a gauge length of 80 mm (INSTRON® Model 5965 Tensile Tester with Built-in Convection Oven, Illinois Tool Works Inc., Norwood, MA). The PHBV high-density film sample was equilibrated at 120 °C for 1 minute and then uniaxially stretched to twice its original length at a rate of 100% / s. However, the PHBV sample was brittle, and the formation of a porous PHBV membrane with a node and fibril microstructure was not possible. Comparative Example 25: Uniaxially stretched layered composite of porous PTFE tape with high density PHVB film

[0154] Porous PTFE tape (258 μm thick, 28% porosity) was manufactured according to the methodology of U.S. Patent No. 3,953,566 to Gore and cut using a razor blade. A 10 μm thick high-density poly(3-hydroxybutyrate-co-3-hydroxyvalerate) film (obtained from Goodfellow Corporation, Pittsburgh, Pennsylvania) was also cut to the same dimensions and layered on top of the porous PTFE tape. The layered material was sandwiched between two skived PTFE films (non-porous; with release liners) and a metal plate. The sandwiched materials were placed in a hydraulic press (Carver, Inc., Wabash, Indiana) and thermally equilibrated at 175°C for 2 minutes. The thermally equilibrated laminated material was compressed at 500 pounds (approximately 3.45 MPa) for 30 seconds. The skived PTFE film and metal plate were removed to yield a layered PHVB / PTFE composite material. A rectangular specimen measuring 120 mm in length and 10 mm in width was cut from the layered PHVB / PTFE composite with a razor blade and then clamped between two pneumatic clamps with a gauge length of 80 mm (INSTRON® Model 5965 Tensile Tester with Built-in Convection Oven, Illinois Tool Works Inc., Norwood, MA). The layered PHVB / PTFE composite specimen was equilibrated at 120°C for 1 min and then uniaxially stretched to twice its original length at a rate of 100% / s. However, the PHBV layer was damaged, and a porous PHBV membrane with a node and fibril microstructure was not obtained. [Table 2] Example 26: Poly(3-hydroxy-2,2-dimethylbutyrate) (PH(Me) 2 B) Solution preparation

[0155] Poly(3-hydroxy-2,2-dimethylbutyrate) (P3H(Me)2B) was synthesized according to the methodology described in Zhou et al. "Chemically circular, mechanically tough, and melt-processable polyhydroxyalkanoates," Science (2023) 380, 64-69. 0.68 grams of P3H(Me)2B polymer was dried under vacuum at room temperature (approximately 22 °C) for 24 hours. The P3H(Me)2B polymer was then dissolved in 5 mL of chloroform (Sigma Aldrich, St. Louis, MO) in a glass vial at 70 °C for 6 hours using a polytetrafluoroethylene (PTFE) stir bar. The resulting solution was aged at room temperature (approximately 22 °C) for 24 hours. Example 27: Poly(3-hydroxy-2,2-diethylbutyrate) (PH(Et) 2 B) Solution preparation

[0156] P3H(Et)2B is synthesized according to the methodology described in Zhou et al., supra. 10 grams of P3H(Et)2B polymer is dried under vacuum at room temperature (approximately 22°C) for 24 hours. The P3H(Et)2B polymer is then dissolved in 100 mL of chloroform (Sigma Aldrich, St. Louis, MO) under reflux conditions at 75°C for 1 hour in a jacketed glass reactor equipped with a polytetrafluoroethylene (PTFE) stirring blade. The resulting solution is aged at room temperature (approximately 22°C) for 24 hours. Example 28: Preparation of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB4HB) solution

[0157] Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB4HB) is synthesized according to the methodology described in Hori et al., "Chemical synthesis of high molecular weight poly(3-hydroxybutyrate-co-3-hydroxybutyrate)", Polymer (1995) 36(24) 4703-4705. Ten grams of P3HB4HB polymer is dried under vacuum at room temperature (approximately 22°C) for 24 hours. The P3HB4HB polymer is then dissolved in 100 mL of chloroform (Sigma Aldrich, St. Louis, MO) at 75°C for 1 hour under reflux conditions in a jacketed glass reactor equipped with a polytetrafluoroethylene (PTFE) stirring blade. The resulting solution is aged at room temperature (approximately 22°C) for 24 hours. Example 29: Poly(3-hydroxy-2,2-dimethylbutyrate) (PH(Me)) on Polytetrafluoroethylene (PTFE) Substrate with Methanol for Non-Solvent-Induced Phase Separation (NIPS) 2 B) Preparation of the cast tape

[0158] Porous PTFE tape (258 μm thick, 28% porosity) was fabricated according to the methodology of U.S. Patent No. 3,953,566 to Gore. The porous PTFE tape was attached to a glass plate and then coated with 15 mL of the PH(Me)B solution described in Example 25 using a 254 μm drawdown bar. The PH(Me)B-coated PTFE tape was then immediately transferred to a bath filled with methanol (VWR International, LLC, Radnor, PA) at room temperature (approximately 22°C) for non-solvent-induced phase separation. The PH(Me)B-coated PTFE tape was kept in the methanol bath for at least 5 minutes until solvent exchange was complete. The solvent-exchanged PH(Me)B / PTFE tape was removed from the methanol bath and air-dried at room temperature (approximately 22°C) for 24 hours to remove excess solvent. Example 30: Poly(3-hydroxy-2,2-dimethylbutyrate) (PH(Me)) on Polyethylene (PE) Substrate with Methanol for Non-Solvent-Induced Phase Separation (NIPS) 2 B) Preparation of the cast tape

[0159] A 304.8 μm drawdown bar was used to coat a porous ultra-high molecular weight polyethylene (PE) tape (manufactured according to the methodology described in U.S. Pat. No. 10,577,468 to Sbriglia) with a thickness of 185 μm and a porosity of 25% with 5 mL of P3H(Me)2B solution prepared as described in Example 26. The P3H(Me)2B-coated PE tape was immediately immersed in a bath filled with methanol (VWR International, LLC) at room temperature (approximately 22°C) for non-solvent-induced phase separation. The P3H(Me)2B-coated PE tape was kept in the methanol bath for 5 minutes until the solvent exchange was complete. The solvent-exchanged P3H(Me)2B / PE tape was removed from the bath and air-dried at room temperature (approximately 22°C) for 24 hours to remove excess solvent. Example 31: Poly(3-hydroxy-2,2-diethylbutyrate) (PH(Et)) on Polytetrafluoroethylene (PTFE) Substrate with Methanol for Non-Solvent-Induced Phase Separation (NIPS) 2 B) Preparation of the cast tape

[0160] Porous PTFE tape (258 μm thick, 28% porosity) was prepared according to the methodology of U.S. Patent No. 3,953,566 to Gore. The porous PTFE tape was attached to a glass plate and then coated with 15 mL of P3H(Et)2B solution prepared as described in Example 27 using a 254 μm drawdown bar. The P3H(Et)2B-coated PTFE tape was then immediately transferred to a bath filled with methanol (VWR International, LLC, Radnor, PA) at room temperature (approximately 22° C.) for non-solvent-induced phase separation. The P3H(Et)2B-coated PTFE tape was kept in the methanol bath for at least 5 minutes until the solvent exchange was complete. The solvent-exchanged P3H(Et)2B / PTFE tape was removed from the bath and air-dried at room temperature (approximately 22° C.) for 24 hours to remove excess solvent. Example 32: Poly(3-hydroxy-2,2-diethylbutyrate) (PH(Et)) on Polyethylene (PE) Substrate with Methanol for Non-Solvent-Induced Phase Separation (NIPS) 2 B) Preparation of the cast tape

[0161] A porous ultra-high molecular weight polyethylene (PE) tape (manufactured according to the methodology disclosed in U.S. Pat. No. 10,577,468 to Sbriglia) with a thickness of 185 μm and a porosity of 25% was coated with 10 mL of the P3H(Et)2B solution prepared as described in Example 27 using a 254 μm drawdown bar. The P3H(Et)2B-coated PE tape was immediately immersed in a bath filled with methanol (VWR International, LLC) at room temperature (approximately 22° C.) for non-solvent-induced phase separation. The P3H(Et)2B-coated PE tape was kept in the methanol bath for 5 minutes until the solvent exchange was complete. The solvent-exchanged P3H(Et)2B / PE tape was removed from the bath and air-dried at room temperature (approximately 22° C.) for 24 hours to remove excess solvent. Example 33: Preparation of Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB4HB) Cast Tapes on Polytetrafluoroethylene (PTFE) Substrates Using Methanol for Non-Solvent-Induced Phase Separation (NIPS)

[0162] Porous PTFE tape (258 μm thick, 28% porosity) was prepared according to the methodology of U.S. Patent No. 3,953,566 to Gore. The porous PTFE tape was attached to a glass plate and then coated with 15 mL of the P3HB4HB solution prepared as described in Example 28 using a 254 μm drawdown bar. The P3HB4HB-coated PTFE tape was then immediately transferred to a bath filled with methanol (VWR International, LLC, Radnor, PA) at room temperature (approximately 22° C.) for non-solvent-induced phase separation. The P3HB4HB-coated PTFE tape was kept in the methanol bath for at least 5 minutes until the solvent exchange was complete. The solvent-exchanged P3HB4HB / PTFE tape was removed from the bath and air-dried at room temperature (approximately 22° C.) for 24 hours to remove excess solvent. Example 34: Preparation of Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB4HB) Cast Tapes on Polyethylene (PE) Substrates Using Methanol for Non-Solvent-Induced Phase Separation (NIPS)

[0163] A 254 μm drawdown bar is used to coat a porous ultra-high molecular weight polyethylene (PE) tape (manufactured according to the methodology described in U.S. Pat. No. 10,577,468 to Sbriglia) with a thickness of 185 μm and a porosity of 25% with 10 mL of the P3HB4HB solution prepared as described in Example 28. The P3HB4HB-coated PE tape is immediately immersed in a bath filled with methanol (VWR International, LLC) at room temperature (approximately 22° C.) for non-solvent-induced phase separation. The P3HB4HB-coated PE tape is kept in the methanol bath for 5 minutes until the solvent exchange is complete. The solvent-exchanged P3HB4HB / PE tape is removed from the bath and air-dried at room temperature (approximately 22° C.) for 24 hours to remove excess solvent. Example 35: Uniaxially Stretched Poly(3-hydroxy-2,2-dimethylbutyrate) (PH(Me) 2 B) Membrane preparation

[0164] The P3H(Me)2B / PE tape prepared according to Example 30 was used as the starting material. A rectangular specimen (12.5 mm wide, 75.4 mm long) was cut from the P3H(Me)2B / PE tape. The rectangular specimen was loaded between two pneumatic jaws with a 30 mm gauge length (INSTRON® Model 5965 tensile tester with a built-in convection oven, Illinois Tool Works Inc., Norwood, Massachusetts) and allowed to thermally equilibrate at 120°C for 2 minutes. The rectangular specimen was then uniaxially stretched to 1.4 times its original length at a strain rate of 10% / s. This process produced a uniaxially stretched porous P3H(Me)2B membrane with a node and fibril microstructure. Example 36: Preparation of uniaxially stretched poly(3-hydroxy-2,2-diethylbutyrate) membrane

[0165] The P3H(Et)2B / PE tape prepared according to Example 32 is used as the starting material. A rectangular sample (70 mm wide, 150 mm long) is cut from the P3H(Et)2B / PE tape. The rectangular sample is loaded into a Karo IV biaxial stretching machine (Brueckner Maschinenbau GmbH & Co., Siegsdorf, Germany) and thermally equilibrated at 120°C for 2 minutes. The rectangular sample is then uniaxially stretched to four times its original length at a strain rate of 10% / s. The uniaxially stretched P3H(Et)2B film is removed from the PE substrate. This process produces a uniaxially stretched porous P3H(Et)2B film with a node and fibril microstructure. Example 37: Preparation of uniaxially stretched poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB4HB) membrane The P3HB4HB / PE tape prepared according to Example 34 is used as the starting material. A rectangular sample (70 mm wide, 150 mm long) is cut from the P3HB4HB / PE tape. The rectangular sample is loaded into a Karo IV biaxial stretching machine (Brueckner Maschinenbau GmbH & Co., Siegsdorf, Germany) and thermally equilibrated at 120°C for 2 minutes. The rectangular sample is then uniaxially stretched to four times its original length at a strain rate of 10% / s. The uniaxially stretched P3HB4HB film is removed from the PE substrate. This process produces a uniaxially stretched porous P3HB4HB film with a node and fibril microstructure. Example 38: Biaxially oriented poly(3-hydroxy-2,2-dimethylbutyrate) (PH(Me) 2 B) Membrane preparation

[0166] P3H(Me)2B-coated polyethylene tape (P3H(Me)2B / PTFE) was prepared according to Example 29. Rectangular specimens measuring 70 mm in width (transverse direction; TD) and 150 mm in length (machine direction; MD) were cut from the P3H(Me)2B / PTFE tape. The rectangular specimens were loaded into a Karo IV biaxial stretching machine (Brueckner Maschinenbau GmbH & Co.) and thermally equilibrated at 120 °C for 2 min. The rectangular specimens were (simultaneously) biaxially stretched in both MD and TD at a strain of 100% / s until an area ratio of 4 was reached. This process produced biaxially stretched P3H(Me)2B porous membranes containing nodes and fibrils. Example 39: Biaxially oriented poly(3-hydroxy-2,2-diethylbutyrate) (P3H(Et) 2 B) Membrane preparation

[0167] P3H(Et)2B-coated polyethylene tape (P3H(Et)2B / PTFE) is prepared according to Example 31. Rectangular specimens measuring 70 mm in width (transverse direction; TD) and 150 mm in length (machine direction; MD) are cut from the P3H(Et)2B / PTFE tape. The rectangular specimens are loaded into a Karo IV biaxial stretching machine (Brueckner Maschinenbau GmbH & Co.) and thermally equilibrated at 120°C for 2 minutes. The rectangular specimens are (simultaneously) biaxially stretched in both MD and TD at a strain of 100% / s until an area ratio of 4 is reached. This process produces biaxially stretched P3H(Et)2B porous membranes containing nodes and fibrils. Example 40: Preparation of biaxially stretched poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB4HB) membrane

[0168] P3HB4HB-coated polyethylene tape (P3HB4HB / PTFE) is prepared according to Example 33. Rectangular specimens measuring 70 mm in width (transverse direction; TD) and 150 mm in length (machine direction; MD) are cut from the P3HB4HB / PTFE tape. The rectangular specimens are loaded into a Karo IV biaxial stretching machine (Brueckner Maschinenbau GmbH & Co.) and allowed to equilibrate at 120°C for 2 minutes. The rectangular specimens are (simultaneously) biaxially stretched in both MD and TD at a strain of 100% / s until an area ratio of 4 is reached. This process produces biaxially stretched P3HB4HB porous membranes containing nodes and fibrils. Example 41: Preparation of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB4HB) solution

[0169] Ten grams of P3HB4HB polymer (Helian Polymers, Berveld, The Netherlands) was dried under vacuum at room temperature (approximately 22° C.) for 24 hours. The P3HB4HB polymer was then dissolved in 100 mL of chloroform (Sigma Aldrich, St. Louis, MO) under reflux conditions at 75° C. for 4 hours in a jacketed glass reactor equipped with a polytetrafluoroethylene (PTFE) stirrer blade. The resulting solution was aged at room temperature (approximately 22° C.) for 24 hours. Example 42: Preparation of Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB4HB) Cast Tapes on Polyethylene (PE) Substrates Using Methanol for Nonsolvent-Induced Phase Separation

[0170] A porous ultra-high molecular weight polyethylene (UHMWPE) tape (manufactured according to U.S. Pat. No. 10,577,468 to Sbriglia) with a thickness of 360 μm and a porosity of 26% was coated with the P3HB4HB solution prepared in Example 41 using a 304.8 μm drawdown bar. The P3HB4HB-coated PE tape was immediately immersed in a bath filled with methanol (VWR International, LLC) at room temperature (approximately 22° C.) for non-solvent-induced phase separation. The P3HB4HB-coated PE tape was kept in the methanol bath for 10 minutes until solvent exchange was complete. The solvent-exchanged P3HB4HB / PE tape was removed from the bath and air-dried at room temperature (approximately 22° C.) for 24 hours to remove excess solvent. Example 43: Preparation of uniaxially stretched poly(3-hydroxybutyrate-co-4-hydroxybutyrate) membrane

[0171] The P3H4HB / PE tape prepared according to Example 42 was used as the starting material. A rectangular specimen (25.4 mm wide, 75.4 mm long) was cut from the P3H4HB / PE tape. The rectangular specimen was loaded between two pneumatic jaws with a gauge length of 30 mm (INSTRON® Model 5965 tensile tester with built-in convection oven, Illinois Tool Works Inc., Norwood, Massachusetts) and allowed to thermally equilibrate at 60°C for 2 minutes. The rectangular specimen was then uniaxially stretched to 1.4 times its original length at a strain rate of 10% / s. This process produced a uniaxially stretched porous P3H4HB membrane with a node and fibril microstructure. Example 44: Preparation of poly(3-hydroxybutyrate) (P3HB) monofilament

[0172] Poly(3-hydroxybutyrate)-coated polyethylene tape (P3HB / PE) was prepared according to Example 6. Rectangular specimens measuring 70 mm in width (transverse direction; TD) and 150 mm in length (machine direction; MD) were cut from the P3HB / PE tape. The rectangular specimens were loaded into a Karo IV biaxial stretching machine (Brueckner Maschinenbau GmbH & Co.) and thermally equilibrated at 120°C for 2 minutes. The rectangular specimens were (simultaneously) biaxially stretched in both MD and TD at a strain of 100% / s until an area ratio of 9 was reached. The biaxially stretched P3HB film was removed from the PE substrate. The film was then slit to produce monofilaments measuring 1.7 mm in width and 35 μm in thickness with a node and fibril microstructure. Example 45: Preparation of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) monofilament

[0173] Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)-coated polyethylene tape (PHBV / PE) was prepared according to Example 8. Rectangular specimens measuring 70 mm in width (transverse direction; TD) and 150 mm in length (machine direction; MD) were cut from the PHBV / PE tape. The rectangular specimens were loaded into a Karo IV biaxial stretching machine (Brueckner Maschinenbau GmbH & Co.) and thermally equilibrated at 120°C for 2 minutes. The rectangular specimens were simultaneously biaxially stretched in both MD and TD at a strain of 100% / s until an area ratio of 4 was reached. The biaxially stretched PHBV membrane was removed from the PE substrate. The membrane was then slit to produce monofilaments with a width of 1.5 mm and a thickness of 36 μm, possessing a node and fibril microstructure. The monofilaments had a porosity of 84.7%. The disclosure of this application has been described above both generically and with reference to specific embodiments. It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments without departing from the scope of the disclosure. Accordingly, it is intended that the embodiments encompass all modifications and variations of the present disclosure and their equivalents, provided they fall within the scope of the appended claims.

Claims

1. 1. A method comprising: The partially crystalline polyhydroxyalkanoate (PHA) polymer was heated to the melting temperature (T ｍ ) onto the substrate at a deposition temperature below 100° C. to form a PHA-substrate composite; The PHA-substrate composite was heated to a temperature of 1000°C (T ｇ ) and the melting temperature (T ｍ ) to form a porous expanded PHA composite, wherein the porous expanded PHA composite comprises a porous PHA material having a microstructure, the microstructure comprising: A plurality of nodes; a plurality of fibrils interconnecting said plurality of nodes, each of said fibrils defining a fibril axis; and A method comprising:

2. The fibrils comprise extended chain crystals of the PHA polymer oriented along the fibril axis, and the extended chain crystals of the PHA polymer are aligned along the T axis of the PHA polymer before stretching. ｍ The method of claim 1 , wherein the molten metal has a melting temperature greater than 1000 ppm.

3. depositing the partially crystallized PHA polymer dissolving the PHA polymer in a solvent to form a PHA solution; casting the PHA solution onto the substrate; at least partially crystallizing the PHA polymer by partially removing the solvent, adjusting the deposition temperature, or a combination thereof; 3. The method of claim 1 or 2, comprising:

4. The method of any one of claims 1 to 3, further comprising separating the porous PHA material from the porous expanded PHA composite to form a self-supporting porous PHA material.

5. The method of any one of claims 1 to 4, wherein the self-supporting porous PHA material has a porosity of 25% to 99%.

6. The method of any one of claims 1 to 5, wherein the self-supporting porous PHA material is in the form of a membrane, a tube, a sheet, or a three-dimensional shape.

7. The method of any one of claims 1 to 6, wherein the self-supporting porous PHA material has a matrix tensile strength in the machine direction (MD) and / or transverse direction (TD) of at least 5 MPa.

8. The total surface area of ​​the self-supporting porous PHA material per unit mass is 20 m ２ / g~80m ２ The method according to any one of claims 1 to 7, wherein the saturation is 0.05 to 0.

15.

9. The PHA-substrate composite is ｍ The method according to any one of claims 1 to 8, wherein the stretching is carried out at a temperature 10°C lower than that of the film.

10. The method of any one of claims 1 to 9, wherein the PHA-substrate composite is stretched uniaxially, biaxially, or radially.

11. The method according to any one of claims 1 to 10, wherein the PHA-substrate composite is stretched at a rate of 1% / s to 1000% / s.

12. The method of any one of claims 1 to 11, wherein the PHA-substrate composite has a draw ratio of 1:1.1 to 1:

100.

13. 13. The method of any one of claims 1 to 12, wherein the PHA polymer comprises a monomer, homopolymer, or copolymer comprising 3-hydroxybutyrate, 3-hydroxyvalerate, 4-hydroxybutyrate, 3-hydroxyhexanoate, or any combination thereof.

14. 14. The method of any one of claims 1 to 13, wherein the PHA polymer is poly(3-hydroxybutyrate) (PHB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly(4-hydroxybutyrate) (P4HB), poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB4HB), or poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) P(3HB-co-3HHx).

15. The method comprises: Treating the porous expanded PHA composite or the self-supporting porous PHA material to form a modified PHA article. further comprising the treatment comprises coating, imbibing, laminating, or any combination thereof; The method of any one of claims 1 to 14, wherein the modified PHA article is porous or non-porous.

16. The method of any one of claims 1 to 15, further comprising densifying the porous expanded PHA composite, the porous self-supporting porous PHA material, or the modified PHA article to form a densified PHA material.

17. 17. The method of claim 16, wherein the densified PHA material comprises a detectable endotherm associated with the presence of the extended chain crystals of the PHA polymer.

18. 18. The method of claim 16 or claim 17, wherein the densification comprises the application of heat, the application of pressure, stretching, or any combination thereof.

19. The method of any one of claims 1 to 16, wherein the PHA polymer further comprises at least one porogen prior to deposition onto the substrate.

20. 20. The method of claim 19, further comprising removing the porogen before or after stretching the PHA-substrate composite.

21. The method of any one of claims 1 to 16, wherein the substrate is a deformable substrate.

22. 22. The method of claim 21, wherein the deformable substrate is a stretchable polymer.

23. 23. The method of claim 21 or claim 22, wherein the deformable substrate comprises a member selected from polytetrafluoroethylene (PTFE) tape, PTFE film, polyolefin tape, polyolefin film, expanded polyolefin film, ultra-high molecular weight polyethylene (UHMWPE) tape, UHMWPE film, and expanded UHMWPE film.

24. 1. A porous polyhydroxyalkanoate (PHA) material formed from a PHA polymer, the porous PHA material having a microstructure, the microstructure comprising: A plurality of nodes; a plurality of fibrils interconnecting said plurality of nodes, said fibrils defining a fibril axis; and A porous PHA material comprising:

25. The fibrils comprise a plurality of extended chain crystals of the PHA polymer oriented along the fibril axis, and the extended chain crystals of the PHA polymer are the T of the PHA polymer before stretching. ｍ 25. The porous PHA material of claim 24, having a melting temperature greater than

26. 26. The porous PHA material of claim 24 or claim 25, wherein the PHA polymer has a molecular weight of 30,000 g / mol to 10,000,000 g / mol.

27. The porous PHA material according to any one of claims 24 to 26, wherein the porous PHA material has a porosity of 25% to 99%.

28. The porous PHA material according to any one of claims 24 to 27, wherein the porous PHA material is in the form of a membrane, a tube, a sheet, or a three-dimensional shape.

29. The porous PHA material according to any one of claims 24 to 28, wherein the porous PHA material has a matrix tensile strength in the machine direction (MD) and / or transverse direction (TD) of at least 5 MPa.

30. The total surface area of ​​the porous PHA material per unit mass is 20 m ２ The porous PHA material according to any one of claims 24 to 29, wherein the PHA content is greater than 1 / g.

31. 31. The porous PHA material of any one of claims 24 to 30, wherein the PHA polymer comprises a monomer, homopolymer, or copolymer comprising 3-hydroxybutyrate, 3-hydroxyvalerate, 4-hydroxybutyrate, 3-hydroxyhexanoate, or any combination thereof.

32. 32. The porous PHA material of any one of claims 24 to 31, wherein the PHA polymer is poly(3-hydroxybutyrate) (PHB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly(4-hydroxybutyrate) (P4HB), poly(3-hydroxybutyrate-co-4-hydroxybutyrate), or poly(3-hydroxybutyrate-co-hydroxyhexanoate) P(HB-co-HHx).

33. 33. The porous PHA material of any one of claims 24 to 32, wherein the PHA polymer is blended with an additional polymer selected from polylactic acid (PLA), polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), cellulose, polyglycolic acid (PGA), polycaprolactone (PCL), polyvinyl acetate (PVAc), chitin, chitosan, starch, and any combination thereof.

34. A composite comprising the porous PHA material according to any one of claims 24 to 33.

35. 35. The complex of claim 34, wherein the PHA complex is microporous.

36. An article comprising the porous PHA material of any one of claims 24 to 33 or the composite of claim 34 or claim 35.

37. 37. The article of claim 36, wherein the article comprises a woven or nonwoven support substrate.

38. A material comprising a densified expanded polyhydroxyalkanoate having a detectable endotherm associated with the presence of residual extended chain crystals of said PHA polymer, said material having a porosity of less than 10%.

39. Formula I: 【Chemical 1】 or Formula II: 【Chemistry 2】 [In the formula, R １ and R ２ is independently H, or C1-C6 alkyl, or aryl; R ３ is C1-C4 alkyl; X is 2 to 4; n = 3000 to 100,000] 1. A porous polyhydroxyalkanoate (PHA) material formed from a PHA polymer of the formula: Multiple nodes interconnected by fibrils or fibrils only wherein the fibrils have an orientation that defines a fibril axis.

40. The fibrils comprise a plurality of extended chain crystals of the PHA polymer oriented along the fibril axis, and the extended chain crystals of the PHA polymer are the T of the PHA polymer before stretching. ｍ 40. The porous PHA material of claim 39, having a melting temperature greater than

41. 41. The porous PHA material of claim 39 or claim 40, wherein the PHA polymer has a molecular weight of 30,000 g / mol to 10,000,000 g / mol.

42. The porous PHA material according to any one of claims 39 to 41, wherein the porous PHA material has a porosity of 25% to 99%.

43. The porous PHA material according to any one of claims 39 to 42, wherein the porous PHA material is in the form of a membrane, a tube, a sheet, a monofilament, or a three-dimensional shape.

44. 44. The porous PHA material of any one of claims 39 to 43, wherein the porous PHA material has a matrix tensile strength in the machine direction (MD) and / or transverse direction (TD) of at least 5 MPa.

45. The total surface area of ​​the porous PHA material per unit mass is 20 m ２ The porous PHA material according to any one of claims 39 to 44, wherein the PHA content is greater than 1 / g.

46. 46. ​​The porous PHA material of any one of claims 39 to 45, wherein the PHA polymer comprises a monomer, homopolymer, or copolymer comprising 3-hydroxybutyrate, 3-hydroxyvalerate, 4-hydroxybutyrate, 3-hydroxyhexanoate, 3-hydroxy-2,2-dimethylbutyrate, 3-hydroxy-2-methylbutyrate, 3-hydroxy-2-ethylbutyrate, 3-hydroxy-2-methyl-2-ethylbutyrate, 3-hydroxy-2,2-diethylbutyrate, or any combination thereof.

47. 47. The porous PHA material of any one of claims 39 to 46, wherein the PHA polymer is poly(3-hydroxybutyrate) (PHB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly(4-hydroxybutyrate) (P4HB), poly(3-hydroxybutyrate-co-4-hydroxybutyrate), poly(3-hydroxybutyrate-co-hydroxyhexanoate) P(HB-co-HHx), poly(3-hydroxy-2,2-dimethylbutyrate), poly(3-hydroxy-2-methylbutyrate), poly(3-hydroxy-2-ethylbutyrate), poly(3-hydroxy-2,2-diethylbutyrate), or poly(3-hydroxybutyrate-co-4-hydroxybutyrate).

48. 48. The porous PHA material of any one of claims 39 to 47, wherein the PHA polymer is blended with an additional polymer selected from polylactic acid (PLA), polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), cellulose, polyglycolic acid (PGA), polycaprolactone (PCL), polyvinyl acetate (PVAc), chitin, chitosan, starch, and any combination thereof.

49. A composite comprising the porous PHA material of any one of claims 39 to 48.

50. 50. The complex of claim 49, wherein the PHA complex is microporous.

51. An article comprising the porous PHA material of any one of claims 39 to 48 or the composite of claim 49 or claim 50.

52. 52. The article of claim 51 in the form of a membrane, a tube, a sheet, a monofilament article, or a three-dimensional shape.

53. 53. The article of claim 52, wherein the monofilament article is dental floss, medical suture, or fishing line.

54. 52. The article of claim 51, wherein the article comprises a woven or nonwoven support substrate.

55. A woven or knitted fabric comprising the porous PHA material of any one of claims 39 to 48.

56. 56. A wearable garment comprising the woven or knit fabric of claim 55.

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