Method for regulating crystal form and performance of polybutylene adipate based on cis-trans isomer unit

Abstract

The application provides a method for regulating the crystal form and performance of polybutylene adipate based on cis-trans isomerization units, the crystal form of polybutylene adipate is regulated by introducing cis or trans units in the preparation process of polybutylene adipate, and the performance of polybutylene adipate is regulated by changing the introduction amount of cis or trans units; the introduction of cis or trans units is realized by adding cis-2-butene-1,4-diol or trans-2-butene-1,4-diol in the esterification or ester exchange reaction step. The application can effectively and simply change the crystal form of polybutylene adipate by introducing cis and trans units, thereby regulating the degradation rate and toughness of the material, realizing the preparation of polybutylene adipate material with controllable degradation rate and good toughness, and widening the application range of the material. The application does not change the original polymerization process, does not need to add additional additives and solvents, is environmentally friendly, and is conducive to realizing industrialized production.

Description

Technical Field

[0001] This invention relates to biodegradable polymer materials technology, specifically to a method for regulating the crystal form and properties of polybutylene adipate based on cis-trans isomers. Background Technology

[0002] Since the invention of plastics, while plastic products have brought convenience to humankind, they have also caused serious harm to the ecological environment. Statistics show that by 2050, approximately 12 billion tons of plastic waste will be dumped in landfills or the natural environment globally. With increasing societal concern and attention to environmental pollution, biodegradable polymer materials have become the preferred alternative to traditional petroleum-based polymer materials. Due to their excellent biocompatibility, biodegradability, and processability, biodegradable polymer materials are finding increasingly widespread applications in packaging, agriculture, textiles, and biomedicine.

[0003] Most biodegradable polymer materials are crystallizable, and crystalline polymers often have different crystalline structures. Polybutylene adipate (PBA) is a typical polycrystalline biodegradable aliphatic polyester, commonly used as a polyester diol in polyurethane preparation. The crystal form of PBA can be controlled by the crystallization temperature; crystallization above 32°C forms α crystals, while crystallization below 27°C forms β crystals. In addition to crystallization temperature, the crystal form of PBA can also be controlled by methods such as steric confinement (Langmuir 2016,32,3269), the addition of nucleating agents (Ind.Eng.Chem.Res.2012,51,13862), nanofillers (CrystEngComm 2011,13,7129), end-group modification (Phys.Chem.Chem.Phys.2018,20,26479), and random copolymerization (Polym.Degrad.Stab.2006,91,2429). Methods such as space confinement, addition of nucleating agents, and end-group modification all promote the formation of α-crystals. However, space-confined methods have complex preparation processes and produce small amounts of polymer per batch, while end-group modified polymers have low molecular weights, making them unsuitable for industrial production. Furthermore, Chinese patent (CN 106042534B) discloses a method for preparing PBA composites by controlling the crystal structure of nylon 6 fabric. This method involves sandwiching nylon 6 fabric between PBA films to prepare composite materials. By controlling the resin thickness, crystallization temperature, and pressure, different crystal structures of PBA composite materials are prepared, thereby promoting the formation of α-crystals in the composite material.

[0004] Degradation rate is one of the key performance indicators for the use of biodegradable polymer materials; however, controlling the degradation rate of biodegradable polymer materials in specific environments remains challenging. Polymer materials with different crystal structures often exhibit different properties, thus the properties (such as degradation rate and mechanical properties) of materials can be controlled based on polymer crystal structure. The degradation rate of PBA is closely related to its crystal structure; α-crystalline films formed by high-temperature crystallization have a faster degradation rate than β-crystalline films formed by low-temperature crystallization (Polym. Degrad. Stab. 2005, 87, 191). In summary, the crystal structure of PBA can be controlled through various methods, but these all promote the formation of a specific crystal structure (such as α-crystal). It has not been possible to prepare PBA materials with controllable degradation rates and excellent mechanical properties based on the control of PBA material crystal structure. Therefore, providing a simple method for controlling the crystal structure and properties of PBA materials to meet the performance requirements of materials in different applications is crucial for the practical application of PBA materials. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for regulating the crystal form and properties of PBA based on cis-trans isomeric units. By introducing cis and trans units into PBA, the formation of α-crystals and β-crystals is promoted, respectively, thereby preparing PBA materials with controllable degradation rates and good toughness.

[0006] To solve the above-mentioned technical problems, the solution of the present invention is:

[0007] This invention first provides a method for regulating the crystal form and properties of polyphenol oxidase (PBA) based on cis-trans isomers. The method regulates the crystal form of PBA by introducing cis or trans units during the PBA preparation process, and regulates the properties of PBA by changing the amount of cis or trans units introduced. The PBA preparation process includes esterification or transesterification reaction steps to prepare esterified products and polycondensation reaction of esterified products to prepare PBA. The introduction of cis or trans units occurs in the esterification or transesterification reaction steps.

[0008] The cis unit is introduced by adding cis-2-buten-1,4-diol in the esterification or transesterification reaction step, and the trans unit is introduced by adding trans-2-buten-1,4-diol in the esterification or transesterification reaction step.

[0009] The crystal form of PBA was α-crystal by adding cis-2-buten-1,4-diol; the crystal form of PBA was β-crystal by adding trans-2-buten-1,4-diol.

[0010] Increasing the amount of cis-2-buten-1,4-diol accelerates the degradation rate of PBA materials and / or improves their toughness; increasing the amount of trans-2-buten-1,4-diol slows down the degradation rate of PBA materials and / or improves their toughness.

[0011] According to a preferred embodiment of the present invention, the PBA is in the form of α crystal or β crystal; the introduction of the cis unit promotes the formation of α crystal in PBA, and the introduction of the trans unit promotes the formation of β crystal in PBA; the properties are the degradation rate and toughness of PBA.

[0012] According to a preferred embodiment of the present invention, the introduction of cis or trans units during the PBA preparation process specifically includes:

[0013] 1) Esterification or transesterification reaction: Adipic acid or dimethyl adipate, butanediol, cis-2-buten-1,4-diol or trans-2-buten-1,4-diol, catalyst and free radical inhibitor are added to a reactor and reacted at 150-190°C for 3-6 hours to obtain the esterification product; wherein, the molar ratio of the diol to adipic acid or dimethyl adipate is 1.1-1.5; cis-2-buten-1,4-diol or trans-2-buten-1,4-diol accounts for 10%-40% of the total amount of the diol; wherein, the diol is the sum of butanediol and cis-2-buten-1,4-diol or trans-2-buten-1,4-diol;

[0014] 2) Polycondensation reaction: The esterification product from step 1) is reacted at a temperature of 200–230°C and a pressure ≤100 Pa for 2–5 hours to obtain PBA containing cis or trans units; the chemical structural formula of the PBA containing cis or trans units is as follows:

[0015]

[0016] x and y are integers.

[0017] According to a preferred embodiment of the present invention, the catalyst is one or more selected from stannous octoate, tetrabutyl titanate, and tetraisopropyl titanate; the amount of the catalyst is 0.05% to 0.2% of the molar amount of adipic acid or dimethyl adipate.

[0018] According to a preferred embodiment of the present invention, the free radical inhibitor is 4-methoxyphenol; the amount of the free radical inhibitor is 0.5% of the total mass of the reactants.

[0019] According to a preferred embodiment of the present invention, the intrinsic viscosity of the PBA containing cis or trans units is greater than 0.70 dL / g.

[0020] According to a preferred embodiment of the present invention, either cis-2-buten-1,4-diol or trans-2-buten-1,4-diol is added selectively.

[0021] According to a preferred embodiment of the present invention, when a PBA thin film material containing cis-units with a thickness of 0.4 mm is isothermally crystallized at 30°C, the material degradation rate is 0.0262–0.0317 h. -1 It has a Young's modulus of 114–153 MPa, a tensile strength of 14.3–19.1 MPa, and an elongation at break of 701%–791%.

[0022] According to a preferred embodiment of the present invention, when a PBA thin film material containing trans units with a thickness of 0.4 mm is isothermally crystallized at 30°C, the material degradation rate is 0.0143–0.0204 h. -1 It has a Young's modulus of 109–151 MPa, a tensile strength of 14.7–20.3 MPa, and an elongation at break of 709%–806%.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] 1. The PBA material based on cis-trans isomer units provided in this invention has a controllable degradation rate and improves the toughness of the material. The cis-2-butene-1,4-diol monomer can be derived from biomass raw materials, reducing dependence on petroleum resources.

[0025] 2. This invention can effectively and easily change the crystal form of PBA by introducing cis and trans units, thereby controlling the degradation rate and toughness of the material, realizing the preparation of PBA material with controllable degradation rate and good toughness, thus broadening the application range of the material.

[0026] 3. The method for regulating the properties of PBA materials described in this invention is simple and convenient, does not change the original polymerization process, does not require the addition of additional additives and solvents, is environmentally friendly, and is conducive to industrial production. Attached Figure Description

[0027] Figure 1 The images show the 1H NMR spectra of the products obtained in Examples 2, 6 and Comparative Example 1.

[0028] Figure 2 Wide-angle X-ray scattering patterns of the products obtained in Examples 2, 6 and Comparative Example 1.

[0029] Figure 3 The degradation kinetics curves of the products obtained in Examples 2, 6 and Comparative Example 1 are shown. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to specific embodiments:

[0031] The raw materials used in this invention are described below:

[0032] Adipic acid, dimethyl adipate, cis-2-buten-1,4-diol, trans-2-buten-1,4-diol, and Pseudomonas lipase were purchased from Sigma-Aldrich; 4-methoxyphenol, stannous octoate, tetrabutyl titanate, and tetraisopropyl titanate were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0033] The following embodiments are intended to enable those skilled in the art to fully understand the present invention, but do not limit the invention in any way.

[0034] Example 1

[0035] (1) Transesterification reaction: Dimethyl adipate (33.7 g), butanediol (18.0 g), cis-2-buten-1,4-diol (2.0 g), tetrabutyl titanate (132 mg), and 4-methoxyphenol (0.27 g) were added to a reactor and reacted at 150 °C for 6 hours to obtain the esterified product. The content of cis-2-buten-1,4-diol was 0.1 times the molar amount of the diol (butanediol + cis-2-buten-1,4-diol), and the molar ratio of the diol to dimethyl adipate was 1.15.

[0036] (2) Polycondensation reaction: The esterification product of step (1) was reacted for 2 hours at a temperature of 230℃ and a pressure of ≤100Pa to obtain PBA containing cis units.

[0037] Example 2

[0038] (1) Esterification reaction: Adipic acid (31.8 g), butanediol (18.0 g), cis-2-buten-1,4-diol (4.4 g), stannous octoate (88 mg), and 4-methoxyphenol (0.27 g) were added to a reactor and reacted at 190 °C for 3 hours to obtain the esterification product. The content of cis-2-buten-1,4-diol was 0.2 times the molar amount of the diol (butanediol + cis-2-buten-1,4-diol), and the alcohol-acid ratio in the raw materials was 1.15.

[0039] (2) Polycondensation reaction: The esterification product of step (1) was reacted for 5 hours at a temperature of 200℃ and a pressure of ≤100Pa to obtain PBA containing cis units.

[0040] Example 3

[0041] (1) Esterification reaction: Adipic acid (36.3 g), butanediol (18.0 g), cis-2-buten-1,4-diol (7.5 g), isopropyl titanate (71 mg), and 4-methoxyphenol (0.31 g) were added to a reactor and reacted at 180 °C for 5 hours to obtain the esterification product. The content of cis-2-buten-1,4-diol was 0.3 times the molar amount of the diol (butanediol + cis-2-buten-1,4-diol), and the alcohol-acid ratio in the raw materials was 1.15.

[0042] (2) Polycondensation reaction: The esterification product of step (1) was reacted for 5 hours at a temperature of 200℃ and a pressure of ≤100Pa to obtain PBA containing cis units.

[0043] Example 4

[0044] (1) Esterification reaction: Adipic acid (42.4 g), butanediol (18.0 g), cis-2-buten-1,4-diol (11.7 g), stannous octoate (117 mg), and 4-methoxyphenol (0.36 g) were added to a reactor and reacted at 180 °C for 5 hours to obtain the esterification product. The content of cis-2-buten-1,4-diol was 0.4 times the molar amount of the diol (butanediol + cis-2-buten-1,4-diol), and the alcohol-acid ratio in the raw materials was 1.15.

[0045] (2) Polycondensation reaction: The esterification product of step (1) was reacted for 4 hours at a temperature of 210℃ and a pressure of ≤100Pa to obtain PBA containing cis units.

[0046] Example 5

[0047] (1) Transesterification reaction: Dimethyl adipate (33.7 g), butanediol (18.0 g), trans-2-buten-1,4-diol (2.0 g), tetrabutyl titanate (132 mg), and 4-methoxyphenol (0.27 g) were added to a reactor and reacted at 150 °C for 6 hours to obtain the esterified product. The content of trans-2-buten-1,4-diol was 0.1 times the molar amount of the diol (butanediol + trans-2-buten-1,4-diol), and the molar ratio of the diol to dimethyl adipate (alcohol-acid ratio) was 1.15.

[0048] (2) Polycondensation reaction: The esterification product of step (1) was reacted for 2 hours at a temperature of 230℃ and a pressure of ≤100Pa to obtain PBA containing trans units.

[0049] Example 6

[0050] (1) Esterification reaction: Adipic acid (31.8 g), butanediol (18.0 g), trans-2-buten-1,4-diol (4.4 g), stannous octoate (88 mg), and 4-methoxyphenol (0.27 g) were added to a reactor and reacted at 190 °C for 3 hours to obtain the esterification product. The content of trans-2-buten-1,4-diol was 0.2 times the molar amount of the diol (butanediol + trans-2-buten-1,4-diol), and the alcohol-acid ratio in the raw materials was 1.15.

[0051] (2) Polycondensation reaction: The esterification product of step (1) was reacted for 5 hours at a temperature of 200℃ and a pressure of ≤100Pa to obtain PBA containing trans units.

[0052] Example 7

[0053] (1) Esterification reaction: Adipic acid (36.3 g), butanediol (18.0 g), trans-2-buten-1,4-diol (7.5 g), isopropyl titanate (71 mg), and 4-methoxyphenol (0.31 g) were added to a reactor and reacted at 180 °C for 5 hours to obtain the esterification product. The content of trans-2-buten-1,4-diol was 0.3 times the molar amount of the diol (butanediol + trans-2-buten-1,4-diol), and the alcohol-acid ratio in the raw materials was 1.15.

[0054] (2) Polycondensation reaction: The esterification product of step (1) was reacted for 5 hours at a temperature of 200℃ and a pressure of ≤100Pa to obtain PBA containing trans units.

[0055] Example 8

[0056] (1) Esterification reaction: Adipic acid (42.4 g), butanediol (18.0 g), trans-2-buten-1,4-diol (11.7 g), stannous octoate (58.7 mg), and 4-methoxyphenol (0.36 g) were added to a reactor and reacted at 180 °C for 5 hours to obtain the esterification product. The content of trans-2-buten-1,4-diol was 0.4 times the molar amount of the diol (butanediol + trans-2-buten-1,4-diol), and the alcohol-acid ratio in the raw materials was 1.15.

[0057] (2) Polycondensation reaction: The esterification product of step (1) was reacted for 4 hours at a temperature of 210℃ and a pressure of ≤100Pa to obtain PBA containing trans units.

[0058] Comparative Example 1

[0059] (1) Esterification reaction: Adipic acid (25.4g), butanediol (18.0g), stannous octoate (70mg) and 4-methoxyphenol (0.22g) were added to the reactor and reacted at 190℃ for 3 hours to obtain the esterified product.

[0060] (2) Polycondensation reaction: The esterification product of step (1) was reacted for 5 hours at a temperature of 200℃ and a pressure of ≤100Pa to obtain pure PBA.

[0061] Structural analysis and performance testing of samples in the examples:

[0062] 1. The proton NMR spectrum of the sample was measured using a Bruker Avance 500MHz NMR spectrometer. 1 The samples were analyzed by ¹H NMR, and the chemical structure was determined, with the contents of cis and trans units calculated. Deuterated chloroform was used as the solvent, tetramethylsilane as the internal standard, and the test temperature was 25 °C.

[0063] 2. Intrinsic viscosity test: The intrinsic viscosity of the sample was tested in chloroform solvent at 25°C using an Ubbelohde viscometer.

[0064] 3. The crystal form of the sample was analyzed using a wide-angle X-ray scattering spectrometer (WAXS) with an X-ray wavelength of 0.154 nm. The sample was melted at 80 °C for 3 min to eliminate thermal history, and then rapidly transferred to a 30 °C water bath for isothermal crystallization for a certain period of time to allow complete crystallization. The crystallized sample was then analyzed by WAXS.

[0065] 4. Degradation Performance Test: The sample was melted at 80℃ for 3 minutes using a hot press, followed by isothermal crystallization at 30℃ to obtain a thin film material with a thickness of 0.4 mm. The isothermal crystallized film material was cut into blocks of similar mass and size. The blocks were placed in test tubes containing 10 mL of phosphate buffer solution containing lipase and degraded in a constant-temperature shaking water bath at 37℃ for a certain period. After degradation, the samples were removed, washed three times with deionized water, and dried in a vacuum oven to constant weight. The mass was measured, and the degradation rate was calculated. Each sample was tested in triplicate, and the average value was taken. The slope of the degradation rate versus time was used to represent the rate of sample degradation.

[0066] 5. Mechanical property testing: The film, isothermally crystallized at 30℃, was cut into standard dumbbell-shaped strips, approximately 35 mm in length, 3.0 mm in width, and 0.4 mm in thickness. Uniaxial tensile testing was performed using a universal testing machine at a tensile rate of 20.0 mm / min. Each sample was tested five times in parallel, and the average value was taken.

[0067] Table 1. Composition, intrinsic viscosity, and crystal form of the samples prepared in Examples 1-8 and Comparative Example 1

[0068]

[0069] 1 H NMR spectrum results ( Figure 1This demonstrates the successful synthesis of pure PBA and PBA containing cis and trans units. Based on 1 The molar contents of cis and trans units were calculated from the HNMR spectral results, as shown in Table 1. The actual molar contents of cis and trans units are close to the feed ratio. The WAXS curve results ( Figure 2 It can be seen that the introduction of cis and trans units significantly affects the crystal form of PBA. The crystal forms of Examples 1-8 and Comparative Example 1 are shown in Table 1. During isothermal crystallization at 30°C, pure PBA crystallizes to form a mixed crystal of α and β crystals. When the molar content of cis units is 0.10-0.38, PBA containing cis units crystallizes to form α crystals, indicating that the introduction of cis units is beneficial to the formation of α crystals. For PBA containing trans units, when the molar content of trans units is 0.09-0.38, it crystallizes to form β crystals, indicating that the introduction of trans units promotes the formation of β crystals.

[0070] Table 2. Degradation rate and mechanical properties of samples prepared in Examples 1-8 and Comparative Example 1

[0071]

[0072] Table 2 summarizes the degradation rates and mechanical properties of Examples 1-8 and Comparative Example 1. Based on degradation kinetic curves ( Figure 3 The degradation rates of Examples 1-8 and Comparative Example 1 were calculated. The degradation rate of pure PBA was 0.0237 h⁻¹. -1 When the molar content of cis units increased from 0 to 0.38, the degradation rate increased from 0.0237 h⁻¹. -1 Accelerate to 0.0317h -1 This indicates that the introduction of cis units accelerates the degradation rate of PBA materials. However, when the molar content of trans units increases from 0 to 0.38, the degradation rate decreases from 0.0237 h⁻¹. -1 Slowed down to 0.0143h -1 This indicates that the introduction of trans units slows down the degradation rate of PBA materials. Combined with the WAXS results of the samples, it is evident that the introduction of cis units promotes the formation of α-crystals, thereby accelerating the degradation rate of PBA materials; however, the introduction of trans units promotes the formation of β-crystals, thus slowing down the degradation rate of PBA materials.

[0073] The mechanical properties (Table 1) show that pure PBA has a Young's modulus of 160.0 MPa, a tensile strength of 13.8 MPa, and an elongation at break of 680%. When the molar content of cis-units increases from 0 to 0.38, the Young's modulus decreases from 160.0 MPa to 113.5 MPa, the tensile strength increases from 13.8 MPa to 19.1 MPa, and the elongation at break increases from 680% to 791%. When the molar content of trans-units increases from 0 to 0.38, the Young's modulus decreases from 160.0 MPa to 108.5 MPa, the tensile strength increases from 13.8 MPa to 20.3 MPa, and the elongation at break increases from 680% to 806%. These results indicate that the introduction of both cis- and trans-units can improve the toughness of PBA materials, with the trans-unit showing a more significant effect. In summary, the results show that the introduction of cis units accelerates the degradation rate of PBA materials, while the introduction of trans units slows down the degradation rate and improves the toughness of the materials. Therefore, this invention can regulate the crystal form and properties of PBA by introducing cis-trans isomers, thereby obtaining PBA materials with controllable degradation rates and good toughness.

[0074] Finally, it should be noted that the above examples are merely specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the disclosure of this invention should be considered within the scope of protection of this invention.

Claims

1. A method for regulating the crystal form and properties of polybutylene adipate based on cis-trans isomers, characterized in that, The method regulates the crystal form of polybutylene adipate by introducing cis or trans units during the preparation of polybutylene adipate, and regulates the properties of polybutylene adipate by changing the amount of cis or trans units introduced; wherein, the properties are the degradation rate and toughness of polybutylene adipate; the preparation process of polybutylene adipate includes esterification or transesterification reaction steps to prepare esterification products and polycondensation reaction of esterification products to prepare polybutylene adipate, wherein the introduction of cis or trans units occurs in the esterification or transesterification reaction steps; The cis unit is introduced by adding cis-2-buten-1,4-diol in the esterification or transesterification reaction step, and the trans unit is introduced by adding trans-2-buten-1,4-diol in the esterification or transesterification reaction step. The crystal form of polybutylene adipate was controlled to α crystal by adding cis-2-butene-1,4-diol; the crystal form of polybutylene adipate was controlled to β crystal by adding trans-2-butene-1,4-diol. The degradation rate of polybutylene adipate and / or the toughness can be accelerated by increasing the amount of cis-2-buten-1,4-diol; the degradation rate of polybutylene adipate and / or the toughness can be slowed down by increasing the amount of trans-2-buten-1,4-diol.

2. The method for regulating the crystal form and properties of polybutylene adipate based on cis-trans isomers according to claim 1, characterized in that, The specific steps involved in introducing cis or trans units during the preparation of polybutylene adipate are as follows: 1) Esterification or transesterification reaction: Adipic acid or dimethyl adipate, butanediol, cis-2-buten-1,4-diol or trans-2-buten-1,4-diol, catalyst and free radical inhibitor are added to a reactor and reacted at 150-190°C for 3-6 hours to obtain the esterification product; wherein, the molar ratio of the diol to adipic acid or dimethyl adipate is 1.1-1.5; cis-2-buten-1,4-diol or trans-2-buten-1,4-diol accounts for 10%-40% of the total amount of the diol; wherein, the diol is the sum of butanediol and cis-2-buten-1,4-diol or trans-2-buten-1,4-diol; 2) Polycondensation reaction: The esterification product from step 1) is reacted at a temperature of 200–230°C and a pressure ≤100 Pa for 2–5 hours to obtain polybutylene adipate containing cis or trans units; the chemical structural formula of the polybutylene adipate containing cis or trans units is as follows: x and y are integers.

3. The method for regulating the crystal form and properties of polybutylene adipate based on cis-trans isomers according to claim 2, characterized in that, The catalyst is one or more of stannous octoate, tetrabutyl titanate, and tetraisopropyl titanate; the amount of the catalyst used is 0.05% to 0.2% of the molar amount of adipic acid or dimethyl adipate.

4. The method for regulating the crystal form and properties of polybutylene adipate based on cis-trans isomers according to claim 2, characterized in that, The free radical inhibitor is 4-methoxyphenol; the amount of the free radical inhibitor is 0.5% of the total mass of the reactants.

5. The method for regulating the crystal form and properties of polybutylene adipate based on cis-trans isomers according to claim 2, characterized in that, The intrinsic viscosity of the polybutylene adipate containing cis or trans units is greater than 0.70 dL / g.

6. The method for regulating the crystal form and properties of polybutylene adipate based on cis-trans isomers according to claim 2, characterized in that, The cis-2-butene-1,4-diol or trans-2-butene-1,4-diol is added selectively.

7. The method for regulating the crystal form and properties of polybutylene adipate based on cis-trans isomers according to claim 2, characterized in that, When a 0.4 mm thick polybutylene adipate film containing cis-units isothermally crystallized at 30 °C, the degradation rate of the material is 0.0262–0.0317 h⁻¹. -1 It has a Young's modulus of 114–153 MPa, a tensile strength of 14.3–19.1 MPa, and an elongation at break of 701%–791%.

8. The method for regulating the crystal form and properties of polybutylene adipate based on cis-trans isomers according to claim 2, characterized in that, When a 0.4 mm thick polybutylene adipate film containing trans units isothermally crystallized at 30 °C, the material degradation rate was 0.0143–0.0204 h⁻¹. -1 It has a Young's modulus of 109–151 MPa, a tensile strength of 14.7–20.3 MPa, and an elongation at break of 709%–806%.

Images