Pyridyl biodegradable polyester elastomer as well as preparation method and application thereof

Abstract

The invention discloses a pyridyl biodegradable polyester elastomer as well as a preparation method and application thereof. The elastomer is prepared from the following raw materials: picolinic acid or ester thereof, bio-based dibasic acid, bio-based dihydric alcohol and an aliphatic linear dihydroxy compound. According to the invention, a quadruple hydrogen bond cross-linked network is further introduced through combination of melt copolymerization and click chemistry, so that the rebound resilience and degradability of the elastomer are remarkably improved. According to the elastomer prepared by the invention, the tensile strength is greater than 30MPa, the Young modulus is greater than 20MPa, the elongation at break is greater than or equal to 300%, the biodegradation rate is greater than or equal to 85%, and the shore hardness is 20-80D; the density of the supercritical foaming material prepared from the elastomer is less than or equal to 0.10 g / cm < 3 >, the 10,000-time compression deformation rate is less than or equal to 35%, the falling ball rebound resilience is more than or equal to 80%, and the damping G value is less than 12.0. Through unique monomer combination and physical crosslinking design, the problem that the degradability and the mechanical property of a traditional elastomer are difficult to consider at the same time is solved.

Description

Technical Field

[0001] The present invention belongs to the field of bio-based polymer materials, and in particular relates to a pyridine-based biodegradable polyester elastomer and a preparation method and application thereof. Background Art

[0002] The polarity of the molecular structure and the crystallinity of the hard segments significantly influence the properties of polyester elastomers. By adjusting the structure and ratio of the hard segments, the properties of polyester elastomers can be optimized to meet specific application requirements. Pyridinedicarboxylic acid (PDCA) has an aromatic ring structure similar to terephthalic acid (TPA) and furandicarboxylic acid (FDCA) and can be obtained from biomass. Compared to TPA and FDCA, PDCA-based polyesters and their elastomers are a relatively new area of ​​research. The pyridine structural unit can impart specific functionalities to polyester elastomers, such as optical properties, thermal stability, chemical resistance, degradability, mechanical strength, electrochemical properties, antibacterial properties, and selective binding to metal ions. Furthermore, the incorporation of pyridine groups can improve the solubility of polyester elastomers and enhance the solubility of gas molecules, such as CO2, in the polymer matrix. The development of novel biodegradable polyester elastomers based on pyridinedicarboxylic acid offers excellent overall performance and holds broad application prospects.

[0003] Existing polyester elastomers commonly suffer from insufficient resilience and low melt strength, leading to poor foaming properties. Patent CN115322350B utilizes a combination of dipyridinecarboxylic acid and isosorbide, but the claims limit the isosorbide content to 30-80% and do not address physical crosslinking. CN112142963A focuses on 2,6-pyridinedicarboxylic acid and specific dihydroxy compounds, but suffers from limited mechanical properties. Summary of the Invention

[0004] The present invention aims to provide a pyridine-based biodegradable polyester elastomer, its preparation method, and application. By introducing a linear aliphatic dibasic acid to adjust the chain segment flexibility and combining it with click chemistry to construct a quadruple hydrogen bond network, this approach overcomes the bottleneck of existing technologies.

[0005] To achieve the above object, the present invention adopts the following technical solutions: A pyridyl biodegradable polyester elastomer, wherein the raw materials for preparing the pyridyl biodegradable polyester elastomer include: (a) pyridinedicarboxylic acid or its ester; (b) bio-based dibasic acid; (c) bio-based diol; (d) aliphatic linear dihydroxy compound; Wherein, the pyridinedicarboxylic acid is selected from 2,5-pyridinedicarboxylic acid and 2,6-pyridinedicarboxylic acid, the bio-based dibasic acid is selected from sebacic acid and itaconic acid, the bio-based diol is selected from 1,4-butanediol and isosorbide, and the aliphatic linear dihydroxy compound is polytetrahydrofuran; Wherein, the molar ratio of component (a) to component (b) is 0.3-0.7:1.

[0006] Furthermore, the pyridyl biodegradable polyester elastomer has a main chain structure as shown in the following formula: In the formula, Ar is selected from 2,5-pyridine, 2,6-pyridine; R1 is selected from (CH2)4, isosorbide; R2 is (CH2) m , m is an integer ≥2; R3 is (CH2)n, n=2 or 4 or 6 or 8 or 10; x is an integer >0; y is an integer ≥0; z is an integer ≥0.

[0007] The method for preparing the above-mentioned pyridyl biodegradable polyester elastomer comprises the following steps: (1) esterifying or transesterifying pyridine dicarboxylic acid or its esterified product, a bio-based dibasic acid, a bio-based diol, and an aliphatic linear dihydroxy compound under the action of a catalyst and an inert gas atmosphere; the reaction temperature is 130-180° C., and the reaction time is 2-6 hours; (2) adding a heat stabilizer and an antioxidant to the product of step (1), and conducting a polycondensation reaction under vacuum conditions at a temperature of 200-260° C. for 2-12 hours; after cooling the product, adding chloroform to dissolve the product, and subjecting the product to alcohol precipitation, suction filtration, washing, and drying to obtain a pyridyl biodegradable polyester elastomer; wherein the catalyst is selected from isopropyl titanate, tetrabutyl titanate, zinc acetate, antimony acetate, antimony trioxide, stannous octoate, dibutyltin oxide, and lanthanum chloride; the inert gas is selected from nitrogen and argon; the heat stabilizer is selected from triphenyl phosphite, diphenyl phosphite, triphenyl phosphate, phosphate ester, bisphenol A phosphite, trimethyl phosphate, dimethyl phosphate, phosphoric acid, phosphorous acid, hypophosphorous acid, and pyrophosphoric acid; and the antioxidant is selected from antioxidant 1010, antioxidant 1076, antioxidant 168, and antioxidant 1425; The amount of the catalyst is greater than 0.0 wt% of the amount of pyridinedicarboxylic acid or its esters and less than or equal to 0.2 wt% of the amount of pyridinedicarboxylic acid or its esters; the amount of the heat stabilizer is greater than or equal to 0.0 wt% of the amount of pyridinedicarboxylic acid or its esters and less than or equal to 0.2 wt% of the amount of pyridinedicarboxylic acid or its esters; and the amount of the antioxidant is greater than or equal to 0.0 wt% of the amount of pyridinedicarboxylic acid or its esters and less than or equal to 0.2 wt% of the amount of pyridinedicarboxylic acid or its esters.

[0008] The method for preparing the above-mentioned pyridyl biodegradable polyester elastomer comprises the following steps: (1) esterifying or transesterifying pyridine dicarboxylic acid or its esterified product, a bio-based dibasic acid, a bio-based diol, and an aliphatic linear dihydroxy compound under the action of a catalyst and an inert gas atmosphere; the reaction temperature is 130-180° C., and the reaction time is 2-6 hours; (2) adding a heat stabilizer and an antioxidant to the product of step (1) and conducting a polycondensation reaction under vacuum conditions; the reaction temperature is 200-260° C., and the reaction time is 2-12 hours; (3) After cooling the product of step (2), a quadruple hydrogen bond monomer containing ureido pyrimidone is grafted onto the double bond of the bio-based dibasic acid through a thiol-ene click reaction to form a cross-linked network to obtain a pyridyl biodegradable polyester elastomer; wherein the catalyst is selected from isopropyl titanate, tetrabutyl titanate, zinc acetate, antimony acetate, antimony trioxide, stannous octoate, dibutyltin oxide, and lanthanum chloride; the inert gas is selected from nitrogen and argon; the heat stabilizer is selected from triphenyl phosphite, diphenyl phosphite, triphenyl phosphate, phosphate ester, bisphenol A phosphite, trimethyl phosphate, dimethyl phosphate, phosphoric acid, phosphorous acid, hypophosphorous acid, and pyrophosphoric acid; and the antioxidant is selected from antioxidant 1010, antioxidant 1076, antioxidant 168, and antioxidant 1425; Among them, step (3) specifically comprises: after the product of step (2) is cooled, DMF and a thiol-containing ureido pyrimidone derivative are added, and the mixture is reacted at 80-120° C. under reflux conditions for 1-3 hours; after the product is cooled, it is precipitated with alcohol, filtered, washed, and dried to obtain a pyridine-based biodegradable polyester elastomer.

[0009] Application of the above-mentioned pyridine-based biodegradable polyester elastomer in the preparation of supercritical foaming materials.

[0010] Furthermore, the process conditions of the supercritical foaming are as follows: the supercritical fluid is a mixed gas of supercritical CO2 and supercritical N2, the foaming pressure is 5-50 MPa, the foaming temperature is 120-200°C, and the pressure relief rate is greater than 10 MPa / s. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 : Schematic diagram of the quadruple hydrogen bond cross-linking network of the elastomer in Example 5.

[0012] Figure 2 :Example 5 Elastomer 1 HNMR spectrum (solvent: deuterated chloroform CDCl3).

[0013] Figure 3 : SEM image of the cell structure of the supercritical foaming material of Example 10. DETAILED DESCRIPTION

[0014] In order to explain the technical content, structural features, achieved objectives and effects of the technical solution in detail, the following is a detailed description in conjunction with specific embodiments.

[0015] Unless otherwise defined, the meanings of the technical terms used herein are the same as those generally understood by those skilled in the art to which this application belongs; the use of the relevant terms herein is only for the purpose of describing specific embodiments and is not intended to limit this application. It should be noted that, although the above-mentioned embodiments have been described herein, this does not limit the scope of patent protection of the present invention. Therefore, based on the innovative concept of the present invention, changes and modifications to the embodiments described herein, or equivalent structure or equivalent process transformations made using the contents of the specification of the present invention, directly or indirectly applying the above technical solutions to other related technical fields are all included in the scope of patent protection of the present invention.

[0016] The raw materials used in the examples of the present invention are described as follows: Monomer compounds, catalysts, solvents, and raw materials are all commercially available. The preparation method of thiol-containing UPy derivatives is described in Angewandte International Edition Chemie, 56(26), 2017: 7639-7643, specifically the supramonomer (UPy-SH)2 described in that paper, whose structure is as follows:

[0017] The determination methods of tensile strength, Young's modulus, elongation at break, Shore hardness, density, compression set, ball rebound, shock absorption performance, and biodegradability involved in the embodiments of the present invention are specifically described as follows: The tests for tensile strength, Young's modulus and elongation at break shall be carried out in accordance with the relevant provisions of GB / T 1040.2-2006, the test for Shore hardness shall be carried out in accordance with the relevant provisions of SATRATM 205-16, the test for density shall be carried out in accordance with the relevant provisions of ISO 845:2006, the test for compression set shall be carried out in accordance with the relevant provisions of GB T 7759.1-2015, the test for falling ball rebound shall be carried out in accordance with ASTM D3574, the test for shock absorption performance shall be carried out in accordance with GB / T 30907-2014, and the test for biodegradability shall be carried out in accordance with GB / T 29646-2013.

[0018] Example: Example 1 (Elastomer Preparation) 2,5-pyridinedicarboxylic acid (0.3 mol), sebacic acid (0.2 mol), isosorbide (0.4 mol), polytetrahydrofuran (Mn = 2000 g / mol, 0.1 mol) and isopropyl titanate (0.1 wt% of 2,5-pyridinedicarboxylic acid) were added into a three-necked flask at the same time. The temperature was programmed to 160°C under a nitrogen flow and the reaction was carried out for 5 h. Triphenyl phosphate (0.1 wt% of 2,5-pyridinedicarboxylic acid) and antioxidant 1010 (0.1 wt% of 2,5-pyridinedicarboxylic acid) were added and the reaction was carried out at 230°C and 0.1 MPa for 5 h. After the product was cooled to room temperature, 50 mL of chloroform was added to dissolve it and precipitated in 500 mL of methanol. The mixture was then vacuum filtered, the filter cake was washed three times with methanol, and dried in an oven at 50°C for 24 h to obtain an elastomer. The elastomer has a tensile strength of 33 MPa, a Young's modulus of 28 MPa, an elongation at break of 520%, a Shore hardness of 43D, and a biodegradability of 86%.

[0019] Example 2 (Elastomer Preparation) 2,5-Pyridinedicarboxylic acid (0.3 mol), sebacic acid (0.2 mol), 1,4-butanediol (0.4 mol), polytetrahydrofuran (Mn = 2000 g / mol, 0.1 mol) and isopropyl titanate (0.1 wt% of 2,5-pyridinedicarboxylic acid) were added into a three-necked flask at the same time. The temperature was programmed to 160°C under nitrogen flow and the reaction was carried out for 5 h. Triphenyl phosphate (0.1 wt% of 2,5-pyridinedicarboxylic acid) and antioxidant 1010 (0.1 wt% of 2,5-pyridinedicarboxylic acid) were added and the reaction was carried out at 200°C and 0.1 MPa for 5 h. After the product was cooled to room temperature, 50 mL of chloroform was added to dissolve it and precipitated in 500 mL of methanol. The mixture was then vacuum filtered, the filter cake was washed three times with methanol, and dried in an oven at 50°C for 24 h to obtain an elastomer. The elastomer has a tensile strength of 30 MPa, a Young's modulus of 22 MPa, an elongation at break of 580%, a Shore hardness of 40D, and a biodegradability of 88%.

[0020] Example 3 (Elastomer Preparation) 2,5-Pyridinedicarboxylic acid (0.3 mol), sebacic acid (0.2 mol), 1,4-butanediol (0.3 mol), isosorbide (0.1 mol), polytetrahydrofuran (Mn = 2000 g / mol, 0.1 mol) and isopropyl titanate (0.15 wt% of the amount of 2,5-pyridinedicarboxylic acid) were added into a three-necked flask at the same time. The temperature was programmed to 160°C under a nitrogen flow and the reaction was carried out for 5 h. Triphenyl phosphate (0.1 wt% of the amount of 2,5-pyridinedicarboxylic acid) and antioxidant 1010 (0.1 wt% of the amount of 2,5-pyridinedicarboxylic acid) were added and the reaction was carried out at 230°C and 0.1 MPa for 5 h. After the product was cooled to room temperature, 50 mL of chloroform was added to dissolve it and precipitated in 500 mL of methanol. The mixture was then vacuum filtered, the filter cake was washed three times with methanol, and dried in an oven at 50°C for 24 h to obtain an elastomer. The elastomer has a tensile strength of 32 MPa, a Young's modulus of 24 MPa, an elongation at break of 530%, a Shore hardness of 42D, and a biodegradability of 90%.

[0021] Example 4 (Elastomer Preparation) 2,5-pyridinedicarboxylic acid (0.3 mol), sebacic acid (0.1 mol), itaconic acid (0.1 mol), 1,4-butanediol (0.3 mol), isosorbide (0.1 mol), polytetrahydrofuran (Mn = 2000 g / mol, 0.1 mol) and isopropyl titanate (0.15 wt% of 2,5-pyridinedicarboxylic acid) were added to a three-necked flask at the same time, and the temperature was raised to 160 ° C under nitrogen flow and reacted for 5 h. Triphenyl phosphate (0.1 wt% of the 2,5-pyridinedicarboxylic acid) and antioxidant 1010 (0.1 wt% of the 2,5-pyridinedicarboxylic acid) were added and reacted at 230°C and 0.1 MPa for 5 hours. After the product cooled to room temperature, 50 mL of chloroform was added to dissolve it and precipitated it in 500 mL of methanol. The mixture was then vacuum filtered, and the filter cake was washed three times with methanol. It was then dried in a 50°C oven for 24 hours to obtain an elastomer. The elastomer had a tensile strength of 36 MPa, a Young's modulus of 35 MPa, an elongation at break of 570%, a Shore hardness of 45D, and a biodegradability of 86%.

[0022] Example 5 (Elastomer Preparation) 2,5-pyridinedicarboxylic acid (0.3 mol), sebacic acid (0.1 mol), itaconic acid (0.1 mol), 1,4-butanediol (0.3 mol), isosorbide (0.1 mol), polytetrahydrofuran (Mn = 2000 g / mol, 0.1 mol) and isopropyl titanate (0.15 wt% of 2,5-pyridinedicarboxylic acid) were added into a three-necked flask at the same time. The temperature was raised to 160 ° C under nitrogen flow and the reaction was carried out for 5 h. Triphenyl phosphate (0.1 wt% of 2,5-pyridinedicarboxylic acid) and antioxidant 1010 (0.1 wt% of 2,5-pyridinedicarboxylic acid) were added and the reaction was carried out at 230 ° C and 0.1 MPa for 5 h. After the product was cooled to room temperature, 50 mL of DMF and thiol-containing UPy derivative (0.1 mol) were reacted under reflux for 3 h. After the product was cooled to room temperature, it was precipitated in 500 mL of methanol and then vacuum filtered. The filter cake was washed with methanol 3 times and dried in an oven at 50 ° C for 24 h to obtain an elastomer (cross-linked as shown in FIG. Figure 1 The corresponding H NMR spectrum is as follows Figure 2 The elastomer has a tensile strength of 48 MPa, a Young's modulus of 40 MPa, an elongation at break of 620%, a 500% deformation recovery rate of 90%, a Shore hardness of 58D, and a biodegradability of 85%.

[0023] Comparative Example 1 (traditional PBAT polyester elastomer) Tensile strength 18-36MPa, Young's modulus 25-30MPa, elongation at break 560-750%, Shore hardness ≥80D, biodegradability >80%.

[0024] Example 6 (supercritical foaming material) The elastomer of Example 1 was foamed at 40 MPa (pressure ratio: supercritical CO2:supercritical N2=3:1) and 170°C with a pressure relief rate of 15 MPa / s. The resulting supercritical foamed material had a density of 0.08 g / cm 3 , the ball rebound is 83%, the shock absorption G value is 10.7, and the rebound is maintained at 68% after 10,000 compression tests.

[0025] Example 7 (supercritical foaming material) The elastomer of Example 2 was foamed at 35 MPa (pressure ratio: supercritical CO2:supercritical N2=4:1) and 160°C with a pressure relief rate of 12 MPa / s. The resulting supercritical foamed material had a density of 0.07 g / cm 3 , the rebound resilience of the falling ball is 85%, the shock absorption G value is 10.5, and the rebound resilience remains 70% after 10,000 compressions.

[0026] Example 8 (supercritical foaming material) The elastomer of Example 3 was foamed at 45 MPa (pressure ratio: supercritical CO2:supercritical N2=2:1) ​​and 150°C with a pressure relief rate of 20 MPa / s. The resulting supercritical foamed material had a density of 0.08 g / cm 3 , the rebound resilience of the falling ball is 84%, the shock absorption G value is 10.8, and the rebound resilience remains 70% after 10,000 compressions.

[0027] Example 9 (supercritical foaming material) The elastomer of Example 4 was foamed at 30 MPa (pressure ratio: supercritical CO2:supercritical N2=1:1) and 140°C, with a pressure release rate of 8 MPa / s. The resulting supercritical foamed material had a density of 0.09 g / cm 3 , the rebound resilience of the falling ball is 82%, the shock absorption G value is 11.5, and the rebound resilience is maintained at 65% after 10,000 compressions.

[0028] Example 10 (Supercritical Foaming Material) The elastomer of Example 5 was subjected to a pressure reduction rate of 8 MPa / s at 30 MPa (pressure ratio: supercritical CO2:supercritical N2=1:1) and 140°C. The cell structure of the obtained supercritical foamed material is as follows: Figure 3 , density 0.06g / cm 3 , the ball rebound is 88%, the shock absorption G value is 8.5, and the rebound resilience remains 75% after 10,000 compressions.

[0029] Comparative Example 2 (commercially available EVA supercritical foaming material) Density 0.15-0.20g / cm 3 , the ball rebound is 40-45%, the shock absorption G value is 10-12, and the rebound retention rate after 10,000 compressions is <50%.

[0030] Table 1: Summary and comparison of various performance parameters of the elastomers of Examples 1-5 and Comparative Example 1 Table 2: Summary and comparison of various performance parameters of supercritical foaming materials of Examples 6-10 and Comparative Example 2

Claims

1. A pyridyl biodegradable polyester elastomer, characterized in that: The raw materials for preparing the pyridine-based biodegradable polyester elastomer include: (a) pyridinedicarboxylic acid or its ester; (b) bio-based dibasic acid; (c) bio-based diol; (d) aliphatic linear dihydroxy compound; Wherein, the pyridinedicarboxylic acid is selected from 2,5-pyridinedicarboxylic acid and 2,6-pyridinedicarboxylic acid, the bio-based dibasic acid is selected from sebacic acid and itaconic acid, the bio-based diol is selected from 1,4-butanediol and isosorbide, and the aliphatic linear dihydroxy compound is polytetrahydrofuran; Wherein, the molar ratio of component (a) to component (b) is 0.3-0.7:

1.

2. The pyridyl biodegradable polyester elastomer according to claim 1, characterized in that: The pyridyl biodegradable polyester elastomer has a main chain structure shown in the following formula: ， In the formula, Ar is selected from 2,5-pyridine, 2,6-pyridine; R1 is selected from (CH2)4, isosorbide; R2 is (CH2) m , m is an integer ≥2; R3 is (CH2)n, n=2 or 4 or 6 or 8 or 10; x is an integer >0; y is an integer ≥0; z is an integer ≥0.

3. A method for preparing a pyridyl biodegradable polyester elastomer according to any one of claims 1 to 2, characterized in that: The following steps are involved: (1) esterifying or transesterifying pyridine dicarboxylic acid or its esterified product, a bio-based dibasic acid, a bio-based diol, and an aliphatic linear dihydroxy compound under the action of a catalyst and an inert gas atmosphere; the reaction temperature is 130-180° C., and the reaction time is 2-6 hours; (2) adding a heat stabilizer and an antioxidant to the product of step (1), and conducting a polycondensation reaction under vacuum conditions at a temperature of 200-260° C. for 2-12 hours; After the product is cooled, chloroform is added to dissolve it, and the product is precipitated with alcohol, filtered, washed, and dried to obtain a pyridyl biodegradable polyester elastomer.

4. The preparation method according to claim 3, wherein: The catalyst is selected from isopropyl titanate, tetrabutyl titanate, zinc acetate, antimony acetate, antimony trioxide, stannous octoate, dibutyltin oxide, and lanthanum chloride; the inert gas is selected from nitrogen and argon; the thermal stabilizer is selected from triphenyl phosphite, diphenyl phosphite, triphenyl phosphate, phosphate ester, bisphenol A phosphite, trimethyl phosphate, dimethyl phosphate, phosphoric acid, phosphorous acid, hypophosphorous acid, and pyrophosphoric acid; and the antioxidant is selected from antioxidant 1010, antioxidant 1076, antioxidant 168, and antioxidant 1425.

5. The preparation method according to claim 3, wherein: The amount of the catalyst is greater than 0.0 wt% of the amount of pyridinedicarboxylic acid or its esters and less than or equal to 0.2 wt% of the amount of pyridinedicarboxylic acid or its esters, the amount of the heat stabilizer is greater than or equal to 0.0 wt% of the amount of pyridinedicarboxylic acid or its esters and less than or equal to 0.2 wt% of the amount of pyridinedicarboxylic acid or its esters, and the amount of the antioxidant is greater than or equal to 0.0 wt% of the amount of pyridinedicarboxylic acid or its esters and less than or equal to 0.2 wt% of the amount of pyridinedicarboxylic acid or its esters.

6. A method for preparing a pyridyl biodegradable polyester elastomer according to any one of claims 1 to 2, characterized in that: The following steps are involved: (1) esterifying or transesterifying pyridine dicarboxylic acid or its esterified product, a bio-based dibasic acid, a bio-based diol, and an aliphatic linear dihydroxy compound under the action of a catalyst and an inert gas atmosphere; the reaction temperature is 130-180° C., and the reaction time is 2-6 hours; (2) adding a heat stabilizer and an antioxidant to the product of step (1) and conducting a polycondensation reaction under vacuum conditions; the reaction temperature is 200-260° C., and the reaction time is 2-12 hours; (3) After cooling, the product of step (2) is subjected to a thiol-ene click reaction to graft a quadruple hydrogen bond monomer containing ureido pyrimidone onto the double bond of the bio-based dibasic acid to form a cross-linked network, thereby obtaining a pyridyl biodegradable polyester elastomer.

7. The preparation method according to claim 6, characterized in that: The catalyst is selected from isopropyl titanate, tetrabutyl titanate, zinc acetate, antimony acetate, antimony trioxide, stannous octoate, dibutyltin oxide, and lanthanum chloride; the inert gas is selected from nitrogen and argon; the thermal stabilizer is selected from triphenyl phosphite, diphenyl phosphite, triphenyl phosphate, phosphate ester, bisphenol A phosphite, trimethyl phosphate, dimethyl phosphate, phosphoric acid, phosphorous acid, hypophosphorous acid, and pyrophosphoric acid; and the antioxidant is selected from antioxidant 1010, antioxidant 1076, antioxidant 168, and antioxidant 1425.

8. The preparation method according to claim 6, characterized in that: Step (3) is specifically as follows: after the product of step (2) is cooled, DMF and a thiol-containing ureido pyrimidone derivative are added, and the mixture is reacted at 80-120° C. under reflux conditions for 1-3 hours; after the product is cooled, it is precipitated with alcohol, filtered, washed, and dried to obtain a pyridine-based biodegradable polyester elastomer.

9. Use of the pyridyl biodegradable polyester elastomer according to any one of claims 1 to 2 in the preparation of supercritical foaming materials.

10. The use according to claim 9, characterized in that: The process conditions of the supercritical foaming are: the supercritical fluid is a mixed gas of supercritical CO2 and supercritical N2, the foaming pressure is 5-50 MPa, the foaming temperature is 120-200°C, and the pressure release rate is greater than 10 MPa / s.

Images