Biodegradable polyesteramide with high melting point and high thermal stability and preparation method thereof

Abstract

The invention relates to biodegradable polyesteramide with high melting point and high thermal stability and a preparation method of the biodegradable polyesteramide. In the formula, the structural formula of-E-is shown in the specification; the structural formula of-A-is shown in the specification; and mixing E and A to obtain a polymerization system, and carrying out melt polycondensation or solid phase polycondensation on the polymerization system to obtain the biodegradable polyesteramide with high melting point and high thermal stability. Wherein the molar ratio of E to A is (0.95-1.05): 1. The polyesteramide disclosed by the invention has high melting point, high mechanical property and stable biodegradability; the whole preparation process is simple and easy to control.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology and relates to a high-melting-point, high-thermal-stability biodegradable polyester amide and its preparation method. Background Technology

[0002] While synthetic polymer materials have propelled human civilization forward, they have also brought about significant environmental problems. Currently, the world generates over 8 billion tons of plastic waste, with less than 10% being effectively recycled; the remainder seeps into every corner of the Earth, from the summit of Mount Everest to the Mariana Trench. To address this challenge, various biodegradable polymers have been developed, but these are primarily aliphatic polyesters, such as polylactic acid (PLA), polyhydroxyalkanoates (PHA), and polybutylene succinate (PBS). These polymers generally suffer from drawbacks such as high cost, poor heat resistance, and susceptibility to pyrolysis, severely restricting their application and development.

[0003] Aliphatic polyesteramides are a class of polymers with both ester and amide bonds in their main chain. Theoretically, they combine the biodegradability of aliphatic polyesters with the excellent thermal and mechanical properties of polyamides, thus holding the promise of becoming a highly distinctive and advantageous biodegradable polymer.

[0004] Japanese Patent JP1995010988A describes a method for preparing aliphatic polyesteramides with significantly reduced melting points by heating a mixture of aliphatic polyester, aliphatic polyamide, and ethylene glycol above their melting points, followed by an ester-amide exchange reaction and then melt polycondensation. Given the considerable randomness and randomness of the ester-amide exchange reaction, leading to a randomized sequence (meaning the product's sequence is difficult to control and its structure resembles a random copolymer), the result is a significant decrease in melting point while simultaneously deteriorating crystallinity.

[0005] Japanese patent JP3617563B2 first dissolves aliphatic polyamide in hydroxycarboxylic acid, then reacts it with a catalyst to generate a low molecular weight polyesteramide prepolymer. Subsequently, an organic solvent is added, and dehydration is performed to prepare polyesteramide. The purpose of using an organic solvent is to solve the problem that the high melting point of aliphatic polyamide leads to excessively high reaction temperatures, causing the hydroxycarboxylic acid to cyclize and thermally decompose, thus preventing the yield of the target product. However, the use of organic solvents poses safety and environmental risks, and also results in a complex process and high cost.

[0006] Japanese Patent JP5207343B2 describes a method for preparing aliphatic polyesteramides by initiating anionic ring-opening polymerization of butyrolactam using sodium metal as a catalyst and polyester oligomers as initiators. The resulting product is a triblock or diblock polymer. This method is chosen because polyesters and polyamide polymers are generally incompatible, and there is a possibility of incompatibility between the polyester and polyamide segments. Furthermore, the anionic ring-opening polymerization of butyrolactam generates a large number of terminal lactam groups, which drastically reduce the thermal stability of the product, making it unsuitable for melt processing.

[0007] Chinese patent CN111019126A prepared aliphatic polyesteramides by using diamine as an initiator and macrocyclic lactones based on diacid diols as monomers through ring-opening-condensation cascade polymerization. However, due to the limited number of introduced amide groups, the product had a low melting point, with the highest melting point being 137℃.

[0008] Chinese patents CN115044035B and CN114891207B both employ a method of preparing high-purity amidation intermediates in a closed aqueous system. These intermediates can then be further processed into sequence-ordered polyesteramides via dehydration esterification polycondensation without the need for separation and purification. The structure of these sequence-ordered polyesteramides is similar to alternating copolymers, with an ester-to-amide bond ratio of 1, equivalent to the corresponding aliphatic polyester. The resulting product exhibits a slightly higher melting point. However, due to the amide sequence length being only approximately 1, stable and perfect polyamide crystals cannot be formed, resulting in a still relatively low melting point, significantly lower than that of the corresponding polyamide.

[0009] The preparation methods mentioned above each have their own advantages, but the resulting aliphatic polyester amides all have low melting points, which affects their heat resistance.

[0010] References 1 (Sequence-Controlled Synthesis of Alternating Poly(ester amide)susing Water as Control Agent in One-Pot[J].Chinese Journal of PolymerScience:1-6[2025-11-24].DOI:10.1007 / s10118-024-3185-6.) and 2 (One-pot synthesis of alternating poly(ester amide)s via water-regulated esterification and amidation sequence [J].Polymer, 2025, 339: 129129. DOI:10.1016 / j.polymer.2025.129129) prepared a series of alternating polyester amides from amino alcohols and adipic acid, but their melting points were below 150℃, which was still not high enough.

[0011] Reference 3 (Comparative Study of Melt and Azeotropic Polymerization on the Structural Evolution and Properties of Quasi-Alternating Polyester Amides[J]. Macromolecules, 2025, 58(15): 8387-98. DOI: 10.1021 / acs.macromol.5c01138) prepared a series of alternating aliphatic polyester amides from lactones (or hydroxy acids), diamines and diacids. Although their melting points were much higher than the corresponding polyesters (70℃), the melting points of these products were still below 170℃, which is still not high enough.

[0012] Chinese patent CN111349233B and reference 4 (Biodegradable Poly(oxamide ester)s from Adipic Acid and Amino Alcohols with Different Chain Lengths: Synthesis, Characterization, and Properties [J]. Macromolecules, 2025, 58(2): 866-76.DOI: 10.1021 / acs.macromol.4c02803) introduce a high hydrogen bond density oxalamide structure into polyesteramide to obtain biodegradable alternating aliphatic polyesteramide with a melting point between 120 and 193 °C. However, due to the easy pyrolysis of the oxalamide structure, the biodegradable alternating aliphatic polyesteramide has poor thermal stability and is prone to yellowing.

[0013] Therefore, it is of great significance to study a high-melting-point, high-thermal-stability biodegradable polyesteramide and its preparation method to solve the above problems. Summary of the Invention

[0014] The purpose of this invention is to solve the problems existing in the prior art and provide a high-melting-point, high-thermal-stability biodegradable polyester amide and its preparation method.

[0015] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0016] A high-melting-point, high-thermal-stability biodegradable polyester amide, with the following structural formula:

[0017] ;

[0018] In the formula, the structural formula for -E- is:

[0019] or ;

[0020] The structural formula of -A- is:

[0021] or ;

[0022] Where n is the degree of polymerization, n ≥ 2; X and Y are the sequence lengths of the polyester segment and the polyamide segment respectively, 1 ≤ X ≤ 50, 2 ≤ Y ≤ 20, 0 ≤ k ≤ X - 1, 0 ≤ P < Y; -R1- is a C4-C10 alkylene group, -R2- is a C2-C10 alkylene group, -R3- and -R5- are each independently a C1-C5 alkylene group, and -R4- is a C4-C10 alkylene group;

[0023] The relationship between X and Y satisfies the following formula:

[0024] ;

[0025] Where when X > 1 is the limiting glass transition temperature of the polymer of -E-, and when X = 1 is the limiting glass transition temperature of the polymer of, in °C; is the limiting glass transition temperature of the polymer of -A-, in °C; The limiting glass transition temperature is the temperature corresponding to when the glass transition temperature no longer rises with the increase in molecular weight; is 58 °C.

[0026] When the relationship between X and Y satisfies the above formula, the glass transition temperature of the high-melting-point and high-thermal-stability biodegradable polyester amide can be made not to exceed 58 °C. The derivation process of the above formula is as follows:

[0027] According to the textbook "Polymer Physics (Fifth Edition)" (edited by Hua Youqing and Jin Riguang, Chemical Industry Press, P155 - 156.), it can be known that = x a + x b where in this textbook is the glass transition temperature of the copolymer, x a is the mole fraction of the repeating unit a, and x b is the mole fraction of the repeating unit b, is the limiting glass transition temperature of the polymer of a, is the limiting glass transition temperature of the polymer of b;

[0028] For the high melting point, high thermal stability, and biodegradable polyester amide of the present invention , and The relationship is: =x A +x E ;x A x is the mole fraction of -A-. E The mole fraction of -E-;

[0029] And x A =Y / (X+Y), x E =X / (X+Y), let =58℃;

[0030] when ≤ At that time, x A +x E ≤ ;

[0031] That is: (Y +X ) / (X+Y)≤ ;

[0032] Therefore: (Y) +X ) ≤ (X+Y)

[0033] Y( - )≤X( - );

[0034] That is: Y≤X( - ) / ( - ).

[0035] To prevent the polyesteramide segments from being frozen under normal composting degradation conditions (composting temperature 58℃±2℃, GB / T 19277.2—2013), the excellent biodegradability of polyesteramide can be ensured.

[0036] The polyesteramide of the present invention is composed of alternating polyester segments (-E-) and polyamide segments (-A-), and the polyamide segments are relatively long (Y≥2), resulting in a high hydrogen bond density. Therefore, the polyesteramide of the present invention exhibits a high melting point.

[0037] The polyesteramide of the present invention also has excellent thermal stability because a large number of aliphatic amide bonds are introduced into the polyesteramide polymer chain. The thermal stability of aliphatic amide bonds is generally much higher than that of aliphatic ester bonds (for example, the thermal decomposition temperature of PA6 (polycaprolactam) is higher than 360°C, while the thermal decomposition temperature of PCL (polycaprolactone) is only 295°C). In particular, the sequence length of polyester and polyamide segments in the present invention is reasonably controlled, and the polyester and polyamide segments are in an alternating structure, which can more effectively improve thermal stability than ordinary random and block copolymers.

[0038] As a preferred technical solution:

[0039] The high-melting-point, high-thermal-stability, biodegradable polyester amide described above has the following -E- structural formula:

[0040] ;

[0041] The structural formula for -A- is:

[0042] ;

[0043] Wherein, 1≤X≤10, 2≤Y≤10 and n(X+Y)≥20, -R1- is C4~C8 alkylene, -R2- is C2~C6 alkylene, and -R4- is C4~C10 alkylene.

[0044] These types of polyesteramides are easier to prepare and have better physical properties: First, the melting point of AABB-type polyamides is generally higher than that of AB-type polyamides at the same amide group density (for example, the melting point of PA66 is about 260℃, which is much higher than that of PA6 at 220℃); Second, the AABB-type polyesteramide system has only 3 monomers, namely HOOC-R1-COOH, NH2-R4-NH2 and HO-R2-OH, while the AB-type polyesteramide system involves 4 monomers (diol, diacid, amino acid and hydroxy alcohol). The more monomers there are, the worse the regularity, the worse the crystallinity, the lower the melting point and the lower the strength.

[0045] As described above, for a high-melting-point, high-thermal-stability, biodegradable polyester amide, the relationship between X and Y satisfies the following formula:

[0046] ;

[0047] in, The temperature is 30℃.

[0048] The high-melting-point, high-thermal-stability biodegradable polyester amide described above has hydroxyl or carboxyl end groups.

[0049] A high melting point and high thermal stability biodegradable polyesteramide as described above, the b value of the high melting point and high thermal stability biodegradable polyesteramide is not greater than 5.

[0050] The end groups of the high melting point and high thermal stability biodegradable polyesteramide provided by the present invention are hydroxyl or carboxyl groups, and there is no terminal amino group. Although the terminal amino group itself does not directly cause the polymer to develop color, it is a typical active group and is prone to oxidation under the conditions of oxygen, high temperature or light, and will gradually generate imines, oximes or other nitrogen oxides. These products usually have colors such as yellow and brown, resulting in yellowing of the polymer. Since the polyesteramide of the present invention does not contain terminal amine groups, it helps to obtain products with excellent hue and can be used to prepare injection molded products, films and fibers.

[0051] The polyesteramide of the present invention has high melting point, high mechanical properties and high stability biodegradability. By introducing amide groups into the polyester, that is, introducing hydrogen bonds, the intermolecular force can be increased, thereby improving the mechanical properties of the polyester. In addition, for general biodegradable polyesteramides, the sequence length Y of the amide repeating units of the present invention is relatively large (Y≥2), which means higher hydrogen bond density, greater intermolecular force, that is, higher mechanical properties.

[0052] A high melting point and high thermal stability biodegradable polyesteramide as described above, the melting point of the high melting point and high thermal stability biodegradable polyesteramide is greater than 193 °C, the biodegradation rate is not less than 60%, and the thermal decomposition temperature is not less than 350 °C.

[0053] The present invention also provides a preparation method of a high melting point and high thermal stability biodegradable polyesteramide. After mixing E and A to obtain a polymerization system, the polymerization system is subjected to melt polycondensation or solid phase polycondensation to obtain a high melting point and high thermal stability biodegradable polyesteramide;

[0054] Among them, the molar ratio of E to A is 0.95~1.05:1;

[0055] The structural formula of E is:

[0056] Or ;

[0057] The structural formula of A is:

[0058] Or ;

[0059] In the formula, 1≤X≤50, 2≤Y≤20, 0≤k≤X - 1, 0≤P<Y; -R1- is a C4~C10 alkylene group, -R2- is a C2~C10 alkylene group, -R3- and -R5- are each independently a C1~C5 alkylene group, and -R4- is a C4~C10 alkylene group;

[0060] The relationship between X and Y satisfies the following formula:

[0061] ;

[0062] Where X>1 The limiting glass transition temperature of E- polymers is Tg when X=1. E for The limiting glass transition temperature of polymers, expressed in °C; The limiting glass transition temperature is the temperature at which the glass transition temperature no longer increases with increasing molecular weight. The temperature is 58℃.

[0063] As a preferred technical solution:

[0064] The preparation method of a high-melting-point, high-thermal-stability biodegradable polyester amide as described above, wherein E is a polyester oligomer or a diol monomer;

[0065] The preparation method of polyester oligomers is as follows: Substance S in a molar ratio of (X-1):1 is reacted with HO-R2-OH (diol) at 140~160℃ until no more water is expelled to obtain polyester oligomers; wherein, substance S is HOOC-R5-OH (hydroxy acid) or its lactone. In this case, 1 < X ≤ 50;

[0066] Alternatively, the polyester oligomer can be prepared by reacting HOOC-R1-COOH (diacid) and HO-R2-OH (diol) in a molar ratio of (X-1):X at 140~160℃ until no more water is discharged to obtain the polyester oligomer, where 1<X≤50.

[0067] The preparation method of a high-melting-point, high-thermal-stability biodegradable polyester amide as described above, wherein the preparation method of A is as follows: water, substance Q and HOOC-R1-COOH (diacarboxylic acid) are added to a reaction vessel and reacted at 160~220℃ for 2~4h in a closed environment to obtain A; wherein, substance Q is an amino acid HOOC-R3-NH2 or its lactam; the molar ratio of substance Q to HOOC-R1-COOH (diacarboxylic acid) is Y:1;

[0068] Alternatively, A can be prepared by adding water, HOOC-R1-COOH (diacarboxylic acid), and H2N-R2-NH2 (diamine) to a reaction vessel and reacting at 160-220℃ for 2-4 hours in a sealed environment to obtain A; wherein the molar ratio of HOOC-R1-COOH (diacarboxylic acid) and H2N-R2-NH2 (diamine) is (Y+1):Y.

[0069] The preparation method of a high-melting-point, high-thermal-stability biodegradable polyester amide as described above also includes the addition of a catalyst during mixing; the catalyst is a Sn catalyst, a Sb catalyst, or a Ti catalyst.

[0070] The preparation method of a high-melting-point, high-thermal-stability biodegradable polyester amide as described above, wherein the mixing temperature is 20~160℃, preferably 20~100℃, and the polymerization system is a heterogeneous mixture at this mixing temperature.

[0071] The preparation method of a high-melting-point, high-thermal-stability biodegradable polyester amide as described above involves a melt polycondensation reaction temperature of 200-260℃, a reaction time of 5-15h, and a reaction pressure of 50-1000Pa.

[0072] The preparation method of high melting point and high thermal stability biodegradable polyester amide as described above involves a solid-phase polycondensation reaction temperature of 140~193℃ and a reaction time of 10~30h. In this invention, the mixing temperature and solid-phase polycondensation temperature are set to low to medium temperatures, below the melting point of the reactants, thereby greatly suppressing the exchange reaction between esters and amides and reducing the randomization of the sequence, which is beneficial to maintaining the high melting point of the polymer product.

[0073] The beneficial effects of this invention are:

[0074] (1) The present invention provides a high-melting-point, high-thermal-stability biodegradable polyesteramide. Through the structural design of polyester sequence, polyamide sequence, and main chain, the polyesteramide is endowed with high melting point, high mechanical properties, and stable biodegradability. Compared with random polyesteramide, it has better crystallinity, higher melting point, and more uniform sequence length, thus exhibiting higher heat resistance and mechanical properties, and more stable biodegradability. Compared with conventional alternating polyesteramide, the polyesteramide of the present invention has a higher melting point and higher strength. Therefore, it is particularly suitable for applications in the fields of fibers and high-performance packaging materials, which helps to overcome the current predicament that biodegradable polymers are difficult to apply in the fiber field, and has broad application prospects and significant economic value.

[0075] (2) The present invention provides a method for preparing a high melting point and high thermal stability biodegradable polyester amide without using organic solvents. In particular, when solid-phase polymerization is used, the polymerization temperature is low, which can yield products with low color value b, controllable structure and high quality. The preparation process is simple and easy to control, easy to achieve large-scale production and low production cost, which has significant economic benefits. Attached Figure Description

[0076] Figure 1 The 1H NMR spectrum of A in Examples 1 and 14 are shown below.

[0077] Figure 2The image shows the 1H NMR spectrum of the high-melting-point, high-thermal-stability biodegradable polyester amide in Example 14. Detailed Implementation

[0078] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0079] Performance index testing method of this invention:

[0080] Thermal properties: The following test conditions were used with a TADSC-Q100 analytical instrument: 5 mg of sample was taken and heated from -20 °C to 260 °C at a heating rate of 20 °C / min under a nitrogen atmosphere; after holding at 260 °C for 2 min, the temperature was lowered to -20 °C at a cooling rate of 20 °C / min; after holding at -20 °C for 2 min, the temperature was raised to 260 °C again at a heating rate of 20 °C / min; the melting point and enthalpy of fusion were determined by the peak temperature and area of ​​the melting peak in the second heating curve.

[0081] Intrinsic viscosity: The test was conducted according to the capillary viscometer method in section 5.1 of GB / T 14190-2017 Test Method for Fiber Grade Polyester Chips, in which the solvent was phenol / 1,1,2,2-tetrachloroethane (mass ratio 50:50).

[0082] Colorimetric b value determination: The colorimetric b value was measured using a spectrophotometer in accordance with GB / T 14190-2017 standard.

[0083] 1H NMR spectrum ( 1 ¹H NMR): diamides, diamines, salts, and polymers 1 1H NMR was performed on a Bruker Avance 600 NMR spectrometer, using either heavy water (D₂O, 4.79 ppm) or deuterated trifluoroacetic acid (TFA) as the solvent. Heavy water was used for salts, while deuterated trifluoroacetic acid (TFA, 11.5 ppm) was used for other substances. Sixteen scans were performed. The degree of polymerization (n) of some polymers was calculated from the resonance peaks of the terminal groups in the 1H NMR spectrum.

[0084] Hydroxyl value: Refer to HG / T 2709-2022. Add the sample to N,N-dimethylformamide and stir continuously on a magnetic stirrer until the sample is completely dissolved. Add the acetylation reagent and stir thoroughly. Add distilled water and stir for 5 min. Add acetone and titrate with potassium hydroxide-methanol standard solution using potentiometric titration. The point of maximum potential change is taken as the titration endpoint.

[0085] Acid value: Refer to GB / T 2895-2008. Weigh the sample into a conical flask, add neutral ethanol, heat it to dissolve in a water bath and then let it cool to room temperature. Titrate potentiometrically with a potassium hydroxide-methanol standard solution, and take the maximum inflection point of the potential change as the titration end point.

[0086] Amine value: Refer to GB / T 38138-2019. Weigh the sample and dissolve it in a mixed solution of m-cresol and isopropanol, stir until completely dissolved, and titrate potentiometrically with a hydrochloric acid-ethanol solution, taking the maximum inflection point of the potential change as the titration end point.

[0087] Biodegradation rate: The biodegradation rate of the poly(ester amide) was tested according to the standard GB / T 19277.1—2025.

[0088] Raw material preparation: The monomer purity of glycolic acid, butyrolactone, caprolactone, glycine, alanine, caprolactam, adipic acid, sebacic acid, dodecanedioic acid, butanediamine, hexanediamine, decanediamine, ethylene glycol, hexanediol and decanediol is greater than or equal to 98%, and they are purchased from TCI or Sigma-Aldrich. The catalysts stannous octoate, antimony oxide and tetrabutyl titanate are purchased from TCI.

[0089] The structural formula of the high melting point and high thermal stability biodegradable poly(ester amide) in the following examples is as follows:

[0090] ;

[0091] In the formula, the structural formula of -E- is:

[0092] or ;

[0093] The structural formula of -A- is:

[0094] or ;

[0095] Among them, n≥2; 1≤X≤50, 2≤Y≤20, 0≤k≤X - 1, 0≤P<Y; -R1- is a C4~C10 alkylene group, -R2- is a C2~C10 alkylene group, -R3- and -R5- are each independently a C1~C5 alkylene group, and -R4- is a C4~C10 alkylene group.

[0096] Example 1

[0097] A preparation method of a high melting point and high thermal stability biodegradable poly(ester amide) is as follows:

[0098] (1) The preparation method of E is: <0008,282>

[0099] In the presence of p-benzenesulfonic acid catalyst, adipic acid and ethylene glycol in a molar ratio of 1:2 were reacted at 160°C until no more water was discharged. After cooling to room temperature, a small amount of deionized water was added to dissolve unreacted monomers and residual catalyst. The mixture was stirred for 10 min, allowed to stand and separate into layers, and the water layer was removed. The mixture was then washed three times with warm water and dried under vacuum overnight at 50°C to obtain E. The molar ratio of p-benzenesulfonic acid to adipic acid was 0.001:1.

[0100] The structural formula for E is:

[0101] ;

[0102] Limiting glass transition temperature of polyester polymers (i.e., -E- polymers) =-22℃, the limiting glass transition temperature is the temperature at which the glass transition temperature no longer increases with the increase of molecular weight;

[0103] (2) The preparation method of A is as follows:

[0104] Water, adipic acid, and hexamethylenediamine were added to a reaction vessel and reacted at 180°C for 2 hours in a sealed environment to obtain A; wherein the molar ratio of adipic acid to hexamethylenediamine was 3:2, and the molar ratio of water to adipic acid was 0.5:1.

[0105] The structural formula for A is:

[0106] ;

[0107] Figure 1 The integrated area of ​​the proton NMR spectrum proves the successful preparation of A;

[0108] The limiting glass transition temperature of polyamide polymers (i.e., -A- polymers) =54.5℃;

[0109] (3) In the presence of stannous octoate, E and A in a molar ratio of 0.95:1 were mixed at 20°C to obtain a polymerization system. After the polymerization reactor was purged with nitrogen three times, the temperature was raised to 200°C at a rate of 5°C / min under nitrogen flow and stirred for 1 hour. Then the nitrogen was turned off, and the temperature was gradually raised to 220°C and the pressure was gradually reduced to 100 Pa within 2 hours. The pressure was then reduced to 50 Pa, and melt polycondensation was carried out at 220°C for 5 hours to obtain a high-melting-point, high-thermal-stability biodegradable polyester amide with the following structural formula: ;

[0110] The molar ratio of stannous octoate to E is 0.002:1, n=35, X=2, Y=2, which satisfies... , It is 30℃;

[0111] The final high-melting-point, high-thermal-stability biodegradable polyester amide has a hydroxyl value of 4.45 mgKOH / g, an acid value of 4.31 mgKOH / g, an ammonia value of 0, an intrinsic viscosity of 1.4 dL / g, a melting point of 197℃, a glass transition temperature of 16.9℃, a thermal decomposition temperature of 359℃, a biodegradation rate of 92%, and a color b value of 4.2.

[0112] Example 2

[0113] A method for preparing a high-melting-point, high-thermal-stability biodegradable polyester amide, comprising the following specific steps:

[0114] (1) The preparation method of E is as follows:

[0115] In the presence of a benzosulfonic acid catalyst, adipic acid and ethylene glycol in a molar ratio of 3:4 were reacted at 160°C until no more water was discharged. After cooling to room temperature, a small amount of deionized water was added to dissolve unreacted monomers and residual catalyst. The mixture was stirred for 10 minutes, allowed to stand and separate into layers, and the water layer was removed. The mixture was then washed three times with warm water and dried overnight under vacuum at 50°C to obtain E. The molar ratio of benzosulfonic acid to adipic acid was 0.001:1.

[0116] The structural formula for E is:

[0117] ;

[0118] The limiting glass transition temperature of polyester polymers (i.e., -E- polymers) =-21℃, the limiting glass transition temperature is the temperature at which the glass transition temperature no longer increases with the increase of molecular weight;

[0119] (2) The preparation method of A is as follows:

[0120] Water, adipic acid, and hexamethylenediamine were added to a reaction vessel and reacted at 180°C for 2 hours in a sealed environment to obtain A; wherein the molar ratio of adipic acid to hexamethylenediamine was 5:4, and the molar ratio of water to adipic acid was 0.5:1.

[0121] The structural formula for A is:

[0122] ;

[0123] The limiting glass transition temperature of polyamide polymers (i.e., -A- polymers) =59℃;

[0124] (3) In the presence of stannous octoate, E and A, weighed in a molar ratio of 1.05:1, were mixed at 80°C to obtain a polymerization system. After the polymerization reactor was purged with nitrogen three times, the temperature was raised to 210°C at a rate of 5°C / min under nitrogen flow and stirred for 1 hour. Then the nitrogen was turned off, and the temperature was gradually raised to 240°C and the pressure was gradually reduced to 100 Pa within 2 hours. The pressure was then reduced to 100 Pa, and melt polycondensation was carried out at 240°C for 5 hours to obtain a high-melting-point, high-thermal-stability biodegradable polyester amide, the structural formula of which is: The molar ratio of stannous octoate to E is 0.003:1, n=20, X=4, Y=4, satisfying the following conditions. , The temperature is 30℃.

[0125] The final high-melting-point, high-thermal-stability biodegradable polyester amide has a hydroxyl value of 3.42 mgKOH / g, an acid value of 3.37 mgKOH / g, an ammonia value of 0, an intrinsic viscosity of 1.3 dL / g, a melting point of 221℃, a glass transition temperature of 17.1℃, a thermal decomposition temperature of 363℃, a biodegradation rate of 91%, and a color b value of 4.7.

[0126] Example 3

[0127] A method for preparing a high-melting-point, high-thermal-stability biodegradable polyester amide, comprising the following specific steps:

[0128] (1) The preparation method of E is as follows:

[0129] In the presence of p-benzenesulfonic acid catalyst, adipic acid and ethylene glycol in a molar ratio of 1:2 were reacted at 160°C until no more water was discharged. After cooling to room temperature, a small amount of deionized water was added to dissolve unreacted monomers and residual catalyst. The mixture was stirred for 10 min, allowed to stand and separate into layers, and the water layer was removed. The mixture was then washed three times with warm water and dried under vacuum overnight at 50°C to obtain E. The molar ratio of p-benzenesulfonic acid to adipic acid was 0.001:1.

[0130] The structural formula for E is:

[0131] ;

[0132] The limiting glass transition temperature of polyester polymers (i.e., -E- polymers) =-22℃, the limiting glass transition temperature is the temperature at which the glass transition temperature no longer increases with the increase of molecular weight;

[0133] (2) The preparation method of A is as follows:

[0134] Water, adipic acid, and hexamethylenediamine were added to a reaction vessel and reacted at 180°C for 2 hours in a sealed environment to obtain A; wherein the molar ratio of adipic acid to hexamethylenediamine was 7:6, and the molar ratio of water to adipic acid was 0.5:1.

[0135] The structural formula for A is:

[0136] ;

[0137] The limiting glass transition temperature of polyamide polymers (i.e., -A- polymers) =60℃;

[0138] (3) In the presence of stannous octoate, E and A, weighed in a molar ratio of 0.95:1, were mixed at 160℃ to obtain a polymerization system. After the polymerization reactor was purged with nitrogen three times, the temperature was raised to 220℃ at a rate of 5℃ / min under nitrogen flow and stirred for 1h. Then the nitrogen was turned off, and the temperature was gradually raised to 260℃ and the pressure was gradually reduced to 100Pa within 2h. The pressure was then reduced to 50Pa, and melt polycondensation was carried out at 260℃ for 5h to obtain a high-melting-point, high-thermal-stability biodegradable polyester amide, the structural formula of which is: The molar ratio of stannous octoate to E is 0.003:1, n=22, X=2, Y=6, satisfying the following conditions. , The temperature is 58℃.

[0139] The final high-melting-point, high-thermal-stability biodegradable polyester amide has a hydroxyl value of 3.57 mgKOH / g, an acid value of 3.48 mgKOH / g, an ammonia value of 0, an intrinsic viscosity of 1.2 dL / g, a melting point of 235℃, a glass transition temperature of 39.5℃, a thermal decomposition temperature of 371℃, a biodegradability of 60%, and a color b value of 4.5.

[0140] Example 4

[0141] A method for preparing a high-melting-point, high-thermal-stability biodegradable polyester amide, comprising the following specific steps:

[0142] (1) The preparation method of E is as follows:

[0143] In the presence of p-benzenesulfonic acid catalyst, adipic acid and ethylene glycol in a molar ratio of 1:2 were reacted at 160°C until no more water was discharged. After cooling to room temperature, a small amount of deionized water was added to dissolve unreacted monomers and residual catalyst. The mixture was stirred for 10 min, allowed to stand and separate into layers, and the water layer was removed. The mixture was then washed three times with warm water and dried under vacuum overnight at 50°C to obtain E. The molar ratio of p-benzenesulfonic acid to adipic acid was 0.001:1.

[0144] The structural formula for E is:

[0145] ;

[0146] The limiting glass transition temperature of polyester polymers (i.e., -E- polymers) =-22℃, the limiting glass transition temperature is the temperature at which the glass transition temperature no longer increases with the increase of molecular weight;

[0147] (2) The preparation method of A is as follows:

[0148] Water, adipic acid, and decanediamine were added to a reaction vessel and reacted at 180°C for 2 hours in a sealed environment to obtain A; wherein the molar ratio of adipic acid to decanediamine was 3:2, and the molar ratio of water to adipic acid was 0.5:1.

[0149] The structural formula for A is:

[0150] ;

[0151] The limiting glass transition temperature of polyamide polymers (i.e., -A- polymers) =52℃;

[0152] (3) In the presence of stannous octoate, E and A, weighed in a molar ratio of 0.95:1, were mixed at 100℃ to obtain a polymerization system. After the polymerization reactor was purged with nitrogen three times, the temperature was raised to 200℃ at a rate of 5℃ / min under nitrogen flow and stirred for 1h. Then the nitrogen was turned off, and the temperature was gradually raised to 220℃ and the pressure was gradually reduced to 100Pa within 2h. The pressure was then reduced to 80Pa, and melt polycondensation was carried out at 220℃ for 6h to obtain a high-melting-point, high-thermal-stability biodegradable polyester amide, the structural formula of which is: The molar ratio of stannous octoate to E is 0.002:1, n=33, X=2, Y=2, which satisfies... , The temperature is 30℃.

[0153] The final high-melting-point, high-thermal-stability biodegradable polyester amide has a hydroxyl value of 4.75 mgKOH / g, an acid value of 4.81 mgKOH / g, an ammonia value of 0, an intrinsic viscosity of 1.1 dL / g, a melting point of 195℃, a glass transition temperature of 15℃, a thermal decomposition temperature of 365℃, a biodegradation rate of 63%, and a color b value of 4.5.

[0154] Example 5

[0155] A method for preparing a high-melting-point, high-thermal-stability biodegradable polyester amide, comprising the following specific steps:

[0156] (1) The preparation method of E is as follows:

[0157] In the presence of a benzosulfonic acid catalyst, dodecanoic acid and ethylene glycol in a molar ratio of 10:11 were reacted at 160°C until no more water was discharged. After cooling to room temperature, a small amount of deionized water was added to dissolve unreacted monomers and residual catalyst. The mixture was stirred for 10 minutes, allowed to stand and separate into layers, and the water layer was removed. The mixture was then washed three times with warm water and dried overnight under vacuum at 50°C to obtain E. The molar ratio of benzosulfonic acid to dodecanoic acid was 0.001:1.

[0158] The structural formula for E is:

[0159] ;

[0160] The limiting glass transition temperature of polyester polymers (i.e., -E- polymers) =-5℃, the limiting glass transition temperature is the temperature at which the glass transition temperature no longer increases with the increase of molecular weight;

[0161] (2) The preparation method of A is as follows:

[0162] Water, dodecanoic acid, and butanediamine were added to a reaction vessel and reacted at 180°C for 2 hours in a sealed environment to obtain A; wherein the molar ratio of dodecanoic acid to butanediamine was 3:2, and the molar ratio of water to dodecanoic acid was 0.5:1.

[0163] The structural formula for A is:

[0164] ;

[0165] The limiting glass transition temperature of polyamide polymers (i.e., -A- polymers) =74℃;

[0166] (3) In the presence of stannous octoate, E and A, weighed in a molar ratio of 0.95:1, were mixed at 100℃ to obtain a polymerization system. After the polymerization reactor was purged with nitrogen three times, the temperature was raised to 220℃ at a rate of 5℃ / min under nitrogen flow and stirred for 1h. Then the nitrogen was turned off, and the temperature was gradually raised to 240℃ and the pressure was gradually reduced to 100Pa within 2h. The pressure was then reduced to 50Pa, and melt polycondensation was carried out at 240℃ for 6h to obtain a high-melting-point, high-thermal-stability biodegradable polyester amide, the structural formula of which is: The molar ratio of stannous octoate to E is 0.006:1, n=19, X=11, Y=2, satisfying the following conditions. , =30℃.

[0167] The final high-melting-point, high-thermal-stability biodegradable polyester amide has a hydroxyl value of 3.38 mgKOH / g, an acid value of 3.42 mgKOH / g, an ammonia value of 0, an intrinsic viscosity of 1.3 dL / g, a melting point of 194℃, a glass transition temperature of 8.5℃, a thermal decomposition temperature of 381℃, a biodegradation rate of 93%, and a color b value of 4.1.

[0168] Example 6

[0169] A method for preparing a high-melting-point, high-thermal-stability biodegradable polyester amide, comprising the following specific steps:

[0170] (1) The preparation method of E is as follows:

[0171] In the presence of p-benzylsulfonic acid catalyst, glycolic acid in a molar ratio of 4:1 was reacted with ethylene glycol at 160°C until no more water was discharged. After cooling to room temperature, a small amount of methanol was added to dissolve unreacted monomers and residual catalyst. The mixture was stirred for 10 min, allowed to stand and separate into layers, and the water layer was removed. The mixture was then washed three times with warm water and dried under vacuum overnight at 50°C to obtain E. The molar ratio of p-benzylsulfonic acid to glycolic acid was 0.001:1.

[0172] The structural formula for E is:

[0173] ;

[0174] The limiting glass transition temperature of polyester polymers (i.e., -E- polymers) =-1℃, the limiting glass transition temperature is the temperature at which the glass transition temperature no longer increases with the increase of molecular weight;

[0175] (2) The preparation method of A is as follows:

[0176] Water, glycine, and sebacic acid were added to a reaction vessel and reacted at 200°C for 2 hours in a sealed environment to obtain A; wherein the molar ratio of glycine to sebacic acid was 5:1, and the molar ratio of water to glycine was 0.5:1.

[0177] The structural formula for A is:

[0178] ;

[0179] The limiting glass transition temperature of polyamide polymers (i.e., -A- polymers) =65℃;

[0180] (3) In the presence of stannous octoate, E and A in a molar ratio of 0.95:1 were mixed at 100℃ to obtain a polymerization system. After the polymerization reactor was purged with nitrogen three times, the temperature was raised to 220℃ at a rate of 4℃ / min under nitrogen flow and stirred for 1h. Then the nitrogen was turned off, and the temperature was gradually raised to 240℃ and the pressure was gradually reduced to 100Pa over 2h. Melt polycondensation was carried out for 5h to obtain a high-melting-point, high-thermal-stability biodegradable polyester amide with the following structural formula: The molar ratio of stannous octoate to E is 0.002:1, n=40, X=5, Y=5. , The temperature is 58℃.

[0181] The final high-melting-point, high-thermal-stability biodegradable polyester amide has a hydroxyl value of 7.9 mgKOH / g, an acid value of 7.68 mgKOH / g, an ammonia value of 0, a melting point of 198℃, a glass transition temperature of 32℃, a thermal decomposition temperature of 355℃, a biodegradation rate of 60%, and a color b value of 5.

[0182] Example 7

[0183] A method for preparing a high-melting-point, high-thermal-stability biodegradable polyester amide, comprising the following specific steps:

[0184] (1) The preparation method of E is as follows:

[0185] In the presence of p-benzylsulfonic acid catalyst, butyrolactone and ethylene glycol in a molar ratio of 9:1 were reacted at 140°C until no more water was discharged. After cooling to room temperature, a small amount of methanol was added to dissolve unreacted monomers and residual catalyst. The mixture was stirred for 10 min, allowed to stand and separate into layers, and the water layer was removed. The mixture was then washed three times with warm water and dried overnight under vacuum at 50°C to obtain E. The molar ratio of p-benzylsulfonic acid to butyrolactone was 0.001:1.

[0186] The structural formula for E is:

[0187] ;

[0188] The limiting glass transition temperature of polyester polymers (i.e., -E- polymers) =-25℃, the limiting glass transition temperature is the temperature at which the glass transition temperature no longer increases with the increase of molecular weight;

[0189] (2) The preparation method of A is as follows:

[0190] Water, GABA, and sebacic acid were added to a reaction vessel and reacted at 210°C for 2 hours in a sealed environment to obtain A; wherein the molar ratio of GABA to sebacic acid was 10:1 and the molar ratio of water to GABA was 0.5:1.

[0191] The structural formula for A is:

[0192] ;

[0193] The limiting glass transition temperature of polyamide polymers (i.e., -A- polymers) =83.2℃;

[0194] (3) In the presence of antimony oxide, E and A, weighed in a molar ratio of 0.95:1, were mixed at 100℃ to obtain a polymerization system. After the polymerization reactor was purged with nitrogen three times, the temperature was raised to 210℃ at a rate of 5℃ / min under a nitrogen flow and stirred for 1 hour. Subsequently, the nitrogen was turned off, and the temperature was gradually raised to 230℃ and the pressure was gradually reduced to 100Pa over 2 hours. Melt polycondensation was carried out for 7 hours to obtain a high-melting-point, high-thermal-stability biodegradable polyester amide, the structural formula of which is: The molar ratio of antimony oxide to E is 0.003:1, n=21, X=10, Y=10, which satisfies... , The temperature is 30℃.

[0195] The final high-melting-point, high-thermal-stability biodegradable polyester amide has a hydroxyl value of 4.16 mgKOH / g, an acid value of 3.96 mgKOH / g, an ammonia value of 0, an intrinsic viscosity of 1.4 dL / g, a melting point of 220℃, a glass transition temperature of 29.1℃, a thermal decomposition temperature of 360℃, a biodegradability of 92%, and a color b value of 5.

[0196] Example 8

[0197] A method for preparing a high-melting-point, high-thermal-stability biodegradable polyester amide, comprising the following specific steps:

[0198] (1) The preparation method of E is as follows:

[0199] In the presence of p-benzenesulfonic acid catalyst, caprolactone and ethylene glycol in a molar ratio of 49:1 were reacted at 140°C until no more water was discharged. After cooling to room temperature, a small amount of methanol was added to dissolve unreacted monomers and residual catalyst. The mixture was stirred for 10 min, allowed to stand and separate into layers, and the water layer was removed. The mixture was then washed three times with warm water and dried under vacuum overnight at 50°C to obtain E. The molar ratio of p-benzenesulfonic acid to caprolactone was 0.001:1.

[0200] The structural formula for E is:

[0201] ;

[0202] The limiting glass transition temperature of polyester polymers (i.e., -E- polymers) =-28℃, the limiting glass transition temperature is the temperature at which the glass transition temperature no longer increases with the increase of molecular weight;

[0203] (2) The preparation method of A is as follows:

[0204] Water, caprolactam, and sebacic acid were added to a reaction vessel and reacted at 220°C for 2 hours in a sealed environment to obtain A; wherein the molar ratio of caprolactam to sebacic acid was 20:1, and the molar ratio of water to caprolactam was 0.5:1.

[0205] The structural formula for A is:

[0206] ;

[0207] The limiting glass transition temperature of polyamide polymers (i.e., -A- polymers) =87.5℃;

[0208] (3) In the presence of tetrabutyl titanate, E and A in a molar ratio of 1:1 were mixed at 80°C to obtain a polymerization system. After the polymerization reactor was purged with nitrogen three times, the temperature was raised to 210°C at a rate of 5°C / min under nitrogen flow and stirred for 1 hour. Then the nitrogen was turned off, and the temperature was gradually raised to 230°C and the pressure was gradually reduced to 100 Pa within 2 hours. The pressure was then reduced to 50 Pa, and melt polycondensation was carried out at 230°C for 6 hours to obtain a high-melting-point, high-thermal-stability biodegradable polyester amide with the following structural formula: The molar ratio of tetrabutyl titanate to E is 0.01:1, n=10, X=50, and Y=20, satisfying the following conditions. , =30℃.

[0209] The final high-melting-point, high-thermal-stability biodegradable polyester amide has a hydroxyl value of 4.75 mgKOH / g, an acid value of 4.81 mgKOH / g, an ammonia value of 0, an intrinsic viscosity of 1.1 dL / g, a melting point of 207℃, a glass transition temperature of 5℃, a thermal decomposition temperature of 390℃, a biodegradation rate of 62%, and a color b value of 5.

[0210] Example 9

[0211] A method for preparing a high-melting-point, high-thermal-stability biodegradable polyester amide, comprising the following specific steps:

[0212] (1) The preparation method of E is as follows:

[0213] In the presence of a benzosulfonic acid catalyst, sebacic acid and hexanediol in a molar ratio of 1:2 were reacted at 160°C until no more water was discharged. After cooling to room temperature, a small amount of deionized water was added to dissolve the unreacted monomer and residual catalyst. The mixture was stirred for 10 minutes, allowed to stand and separate into layers, and the water layer was removed. The mixture was then washed three times with warm water and dried under vacuum overnight at 50°C to obtain E. The molar ratio of benzosulfonic acid to sebacic acid was 0.001:1.

[0214] The structural formula for E is:

[0215] ;

[0216] The limiting glass transition temperature of polyester polymers (i.e., -E- polymers) =-24℃, the limiting glass transition temperature is the temperature at which the glass transition temperature no longer increases with the increase of molecular weight;

[0217] (2) The preparation method of A is as follows:

[0218] Water, GABA, and sebacic acid were added to a reaction vessel and reacted at 220°C for 2 hours in a sealed environment to obtain A; wherein the molar ratio of GABA to sebacic acid was 10:1 and the molar ratio of water to GABA was 0.5:1.

[0219] The structural formula for A is:

[0220] ;

[0221] The limiting glass transition temperature of polyamide polymers (i.e., -A- polymers) =58.5℃;

[0222] (3) In the presence of tetrabutyl titanate, E and A in a molar ratio of 0.95:1 were mixed at 80°C to obtain a polymerization system. After the polymerization reactor was purged with nitrogen three times, the temperature was raised to 210°C at a rate of 5°C / min under nitrogen flow and stirred for 1 hour. Then the nitrogen was turned off, and the temperature was gradually raised to 230°C and the pressure was gradually reduced to 100 Pa within 2 hours. The pressure was then reduced to 50 Pa, and melt polycondensation was carried out at 230°C for 5 hours to obtain a high-melting-point, high-thermal-stability biodegradable polyester amide with the following structural formula: The molar ratio of tetrabutyl titanate to E is 0.002:1, n=28, X=2, Y=10, which satisfies... , The temperature is 58℃.

[0223] The final high-melting-point, high-thermal-stability biodegradable polyester amide has a hydroxyl value of 3.64 mgKOH / g, an acid value of 3.77 mgKOH / g, an ammonia value of 0, an intrinsic viscosity of 1.15 dL / g, a melting point of 211℃, a glass transition temperature of 45℃, a thermal decomposition temperature of 357℃, a biodegradability of 65%, and a color b value of 5.

[0224] Example 10

[0225] A method for preparing a high-melting-point, high-thermal-stability biodegradable polyester amide, comprising the following specific steps:

[0226] (1) The preparation method of A is as follows:

[0227] Water, hexamethylenediamine, and adipic acid were added to a reaction vessel and reacted at 180°C for 4 hours in a sealed environment to obtain A; wherein the molar ratio of hexamethylenediamine to adipic acid was 5:4, and the molar ratio of water to adipic acid was 0.5:1.

[0228] The structural formula for A is:

[0229] ;

[0230] The limiting glass transition temperature of polyamide polymers (i.e., -A- polymers) =59℃; Polyester polymer formed by ethylene glycol and A-terminal adipic acid (i.e. The limiting glass transition temperature Tg of polymers E =-50℃;

[0231] (2) In the presence of tetrabutyl titanate, ethylene glycol and A in a molar ratio of 0.95:1 were mixed at 20°C to obtain a polymerization system. After the polymerization reactor was purged with nitrogen three times, the temperature was raised to 140°C at a rate of 2°C / min under nitrogen flow and stirred for 1 hour. Then the nitrogen was turned off, and the temperature was gradually raised to 190°C and the pressure was gradually reduced to 100 Pa within 2 hours. The pressure was then reduced to 50 Pa, and solid-state polycondensation was carried out at 190°C for 12 hours to obtain a high-melting-point, high-thermal-stability biodegradable polyester amide with the following structural formula: The molar ratio of tetrabutyl titanate to E is 0.003:1, n=35, X=1, Y=4, which satisfies... , The temperature is 58℃.

[0232] The final high-melting-point, high-thermal-stability biodegradable polyester amide has a hydroxyl value of 3.87 mgKOH / g, an acid value of 3.82 mgKOH / g, an ammonia value of 0, an intrinsic viscosity of 1.5 dL / g, a melting point of 232℃, a glass transition temperature of 35℃, a thermal decomposition temperature of 371℃, a biodegradation rate of 91%, and a color b value of 3.1.

[0233] Example 11

[0234] A method for preparing a high-melting-point, high-thermal-stability biodegradable polyester amide, comprising the following specific steps:

[0235] (1) The preparation method of A is as follows:

[0236] Water, hexamethylenediamine, and adipic acid were added to a reaction vessel and reacted at 220°C for 3 hours in a sealed environment to obtain A; wherein the molar ratio of hexamethylenediamine to adipic acid was 5:4, and the molar ratio of water to adipic acid was 0.5:1.

[0237] The structural formula for A is:

[0238] ;

[0239] The limiting glass transition temperature of polyamide polymers (i.e., -A- polymers) =59℃; Polyester polymer formed by ethylene glycol and A-terminal adipic acid (i.e. The limiting glass transition temperature Tg of polymers E =-50℃;

[0240] (2) In the presence of stannous octoate, ethylene glycol and A in a molar ratio of 0.95:1 were mixed at 20°C to obtain a polymerization system. After the polymerization reactor was purged with nitrogen three times, the temperature was raised to 140°C at a rate of 2°C / min under nitrogen flow and stirred for 1 hour. Then the nitrogen was turned off, and the temperature was gradually raised to 140°C and the pressure was gradually reduced to 100 Pa over 2 hours. The pressure was then reduced to 50 Pa, and solid-state polycondensation was carried out at 140°C for 12 hours to obtain a high-melting-point, high-thermal-stability biodegradable polyester amide with the following structural formula: The molar ratio of stannous octoate to E is 0.003:1, n=30, X=1, Y=4, satisfying the following conditions. , The temperature is 58℃.

[0241] The final high-melting-point, high-thermal-stability biodegradable polyester amide has a hydroxyl value of 3.6 mgKOH / g, an acid value of 3.69 mgKOH / g, an ammonia value of 0, an intrinsic viscosity of 1.5 dL / g, a melting point of 227℃, a glass transition temperature of 35℃, a thermal decomposition temperature of 375℃, a biodegradation rate of 91%, and a color b value of 2.8.

[0242] Example 12

[0243] A method for preparing a high-melting-point, high-thermal-stability biodegradable polyester amide, comprising the following specific steps:

[0244] (1) E The preparation method is as follows:

[0245] In the presence of p-benzenesulfonic acid catalyst, adipic acid and ethylene glycol in a molar ratio of 1:2 were reacted at 160°C until no more water was discharged. After cooling to room temperature, a small amount of deionized water was added to dissolve unreacted monomers and residual catalyst. The mixture was stirred for 10 min, allowed to stand and separate into layers, and the water layer was removed. The mixture was then washed three times with warm water and dried under vacuum overnight at 50°C to obtain E. The molar ratio of p-benzenesulfonic acid to adipic acid was 0.001:1.

[0246] The structural formula for E is:

[0247] ;

[0248] The limiting glass transition temperature of polyester polymers (i.e., -E- polymers) =-22℃, the limiting glass transition temperature is the temperature at which the glass transition temperature no longer increases with the increase of molecular weight;

[0249] (2) The preparation method of A is as follows:

[0250] Water, adipic acid, and hexamethylenediamine were added to a reaction vessel and reacted at 220°C for 2 hours in a sealed environment to obtain A; wherein the molar ratio of adipic acid to hexamethylenediamine was 5:4, and the molar ratio of water to adipic acid was 0.5:1.

[0251] The structural formula for A is:

[0252] ;

[0253] The limiting glass transition temperature of polyamide polymers (i.e., -A- polymers) =55℃;

[0254] (3) In the presence of stannous octoate, E and A in a molar ratio of 0.95:1 were mixed at 20°C to obtain a polymerization system. After the polymerization reactor was purged with nitrogen three times, the temperature was raised to 140°C at a rate of 2°C / min under nitrogen flow and stirred for 1 hour. Then the nitrogen was turned off, and the temperature was gradually raised to 193°C and the pressure was gradually reduced to 100 Pa within 2 hours. The pressure was then reduced to 50 Pa, and solid-state polycondensation was carried out at 193°C for 12 hours to obtain a high-melting-point, high-thermal-stability biodegradable polyester amide with the following structural formula: The molar ratio of stannous octoate to E is 0.003:1, n=29, X=2, Y=4. , The temperature is 30℃.

[0255] The final high-melting-point, high-thermal-stability biodegradable polyester amide has a hydroxyl value of 3.4 mgKOH / g, an acid value of 3.45 mgKOH / g, an ammonia value of 0, an intrinsic viscosity of 1.5 dL / g, a melting point of 225℃, a glass transition temperature of 29.5℃, a thermal decomposition temperature of 400℃, a biodegradability of 85%, and a color b value of 3.1.

[0256] Example 13

[0257] A method for preparing a high-melting-point, high-thermal-stability biodegradable polyesteramide is basically the same as in Example 12, except that: after purging the polymerization reactor with nitrogen three times in step (3), the temperature is raised to 210°C and stirred for 1 hour under nitrogen flow at a rate of 5°C / min; then the nitrogen is turned off, and the temperature is gradually raised to 220°C and the pressure is gradually reduced to 100Pa within 2 hours; then the pressure is reduced to 50Pa, and melt polycondensation is carried out at 220°C for 14 hours to obtain a high-melting-point, high-thermal-stability biodegradable polyesteramide, the structural formula of which is: Where n=35, X=2, Y=4, satisfying , The temperature is 30℃.

[0258] The final high-melting-point, high-thermal-stability biodegradable polyester amide has a hydroxyl value of 4.2 mgKOH / g, an acid value of 6.5 mgKOH / g, an ammonia value of 0, an intrinsic viscosity of 1.5 dL / g, a melting point of 220℃, a glass transition temperature of 30℃, a thermal decomposition temperature of 382℃, a biodegradability of 75%, and a color b value of 4.5.

[0259] Example 14

[0260] A method for preparing a high-melting-point, high-thermal-stability biodegradable polyester amide, comprising the following specific steps:

[0261] (1) The preparation method of A is as follows:

[0262] Water, adipic acid, and hexamethylenediamine were added to a reaction vessel and reacted at 180°C for 2 hours in a sealed environment to obtain A; wherein the molar ratio of adipic acid to hexamethylenediamine was 3:2, and the molar ratio of water to adipic acid was 0.5:1.

[0263] The structural formula for A is:

[0264] ;

[0265] Figure 1 The integrated area of ​​the proton NMR spectrum proves the successful preparation of A;

[0266] The limiting glass transition temperature of polyamide polymers (i.e., -A- polymers) =54.5℃;

[0267] (2) In the presence of stannous octoate, ethylene glycol and A in a molar ratio of 0.95:1 were mixed at 20°C to obtain a polymerization system. After the polymerization reactor was purged with nitrogen three times, the temperature was raised to 200°C at a rate of 5°C / min under nitrogen flow and stirred for 1 hour. Then the nitrogen was turned off, and the temperature was gradually raised to 260°C and the pressure was gradually reduced to 100 Pa within 2 hours. The pressure was then reduced to 50 Pa, and melt polycondensation was continued for 5 hours to obtain a high-melting-point, high-thermal-stability biodegradable polyester amide with the following structural formula: ;

[0268] The molar ratio of stannous octoate to ethylene glycol is 0.002:1, n=35, X=1, Y=2, which satisfies... , The limiting glass transition temperature (TgE) of the polyester polymer formed by ethylene glycol and A-terminal adipic acid is -50℃.

[0269] Figure 2 The formation and ratio of ester and amide groups were observed in the proton NMR spectrum, which is consistent with the initial structural design.

[0270] The final high-melting-point, high-thermal-stability biodegradable polyester amide has a hydroxyl value of 4.14 mgKOH / g, an acid value of 3.91 mgKOH / g, an ammonia value of 0, an intrinsic viscosity of 1.5 dL / g, a melting point of 221℃, a glass transition temperature of 19.6℃, a thermal decomposition temperature of 372℃, a biodegradability of 86%, and a color b value of 4.5.

Claims

1. A high-melting-point, high-thermal-stability, biodegradable polyesteramide, characterized in that, The structural formula is: ； In the formula, the structural formula of -E- is: or ; The structural formula of -A- is: or ; Wherein, n≥2; 1≤X≤50, 2≤Y≤20, 0≤k≤X - 1, 0≤P<Y; -R1- is a C4~C10 alkylene group, -R2- is a C2~C10 alkylene group, -R3- and -R5- are each independently a C1~C5 alkylene group, -R4- is a C4~C10 alkylene group; The relationship between X and Y satisfies the following formula: ； Where X>1 The limiting glass transition temperature of E- polymers is Tg when X=1. E for The limiting glass transition temperature of polymers, expressed in °C; The limiting glass transition temperature is the temperature at which the glass transition temperature no longer increases with increasing molecular weight. The temperature is 58℃.

2. The high-melting-point, high-thermal-stability biodegradable polyesteramide according to claim 1, characterized in that, The structural formula of -E- is: ； The structural formula of -A- is: ； Wherein, 1≤X≤10, 2≤Y≤10 and n(X + Y)≥20, -R1- is a C4~C8 alkylene group, -R2- is a C2~C6 alkylene group, -R4- is a C4~C10 alkylene group.

3. A high-melting-point, high-thermal-stability biodegradable polyesteramide according to any one of claims 1 to 2, characterized in that, The relationship between X and Y satisfies the following formula: ； in, The temperature is 30℃.

4. A high-melting-point, high-thermal-stability biodegradable polyesteramide according to any one of claims 1 to 2, characterized in that, The end groups of the high melting point and high thermal stability biodegradable poly(ester amide) are hydroxyl or carboxyl groups.

5. A high-melting-point, high-thermal-stability biodegradable polyesteramide according to any one of claims 1 to 2, characterized in that, The b value of the chromaticity of the high melting point and high thermal stability biodegradable poly(ester amide) is not greater than 5.

6. A high-melting-point, high-thermal-stability biodegradable polyesteramide according to any one of claims 1 to 2, characterized in that, The melting point of the high melting point and high thermal stability biodegradable poly(ester amide) is greater than 193 °C, the biodegradation rate is not less than 60%, and the thermal decomposition temperature is not less than 350 °C.

7. A method for preparing a high-melting-point, high-thermal-stability biodegradable polyester amide, characterized in that, After mixing E and A to obtain a polymerization system, the polymerization system is subjected to melt polycondensation or solid-phase polycondensation to obtain the high melting point and high thermal stability biodegradable poly(ester amide); Wherein, the molar ratio of E to A is 0.95~1.05:1; The structural formula of E is: or ; The structural formula of A is: or ; In the formula, 1≤X≤50, 2≤Y≤20, 0≤k≤X - 1, 0≤P<Y; -R1- is a C4~C10 alkylene group, -R2- is a C2~C10 alkylene group, -R3- and -R5- are each independently a C1~C5 alkylene group, -R4- is a C4~C10 alkylene group; The relationship between X and Y satisfies the following formula: ； Where X>1 The limiting glass transition temperature of E- polymers is Tg when X=1. E for The limiting glass transition temperature of polymers, expressed in °C; The limiting glass transition temperature is the temperature at which the glass transition temperature no longer increases with increasing molecular weight. The temperature is 58℃.

8. The method for preparing a high-melting-point, high-thermal-stability biodegradable polyester amide according to claim 7, characterized in that, E is a polyester oligomer or a diol monomer; The method for preparing polyester oligomers is as follows: Substance S in a molar ratio of (X-1):1 is reacted with HO-R2-OH at 140~160℃ until no more water is released, thus obtaining the polyester oligomer; wherein, substance S is HOOC-R5-OH or... ; Alternatively, the preparation method of the polyester oligomer is: reacting HOOC-R1-COOH and HO-R2-OH with a molar ratio of (X - 1):X at 140~160 °C until no more water is discharged to obtain the polyester oligomer.

9. The method for preparing a high-melting-point, high-thermal-stability biodegradable polyester amide according to claim 7, characterized in that, The preparation method of A is: adding water, substance Q and HOOC-R1-COOH into a reaction kettle, and reacting at 160~220 °C for 2~4 h in a closed environment to obtain A; wherein, substance Q is an amino acid HOOC-R3-NH2 or its lactam; the molar ratio of substance Q to HOOC-R1-COOH is Y:1; Alternatively, the preparation method of A is: adding water, HOOC-R1-COOH and H2N-R2-NH2 into a reaction kettle, and reacting at 160~220 °C for 2~4 h in a closed environment to obtain A; wherein, the molar ratio of HOOC-R1-COOH to H2N-R2-NH2 is (Y + 1):Y.

10. The method for preparing a high-melting-point, high-thermal-stability biodegradable polyester amide according to claim 7, characterized in that, A catalyst is also added during mixing; the catalyst is a Sn catalyst, an Sb catalyst or a Ti catalyst.

11. The method for preparing a high-melting-point, high-thermal-stability biodegradable polyester amide according to claim 7, characterized in that, The mixing temperature is 20~160 °C.

12. The method for preparing a high-melting-point, high-thermal-stability biodegradable polyesteramide according to claim 7, characterized in that, The reaction temperature of melt polycondensation is 200~260 °C, the reaction time is 5~15 h, and the reaction pressure is 50~1000 Pa.

13. The method for preparing a high-melting-point, high-thermal-stability biodegradable polyester amide according to claim 7, characterized in that, The reaction temperature of solid-phase polycondensation is 140~193 °C, and the reaction time is 10~30 h.

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