Preparation method of tetraphenylethylene rigid structure modified PBAT copolyester material

Abstract

The invention relates to the technical field of synthesis of biodegradable polyester high polymer materials, in particular to a preparation method of a tetraphenylethylene rigid structure modified PBAT copolyester material, tetraphenylethylene and PBAT are combined, so that the material has a certain fluorescence property, meanwhile, the crystallinity and mechanical property of the material can be improved, and the material has a good application prospect. The application range of the material is expanded; in order to avoid low reaction activity of 4, 4 '-(2, 2-diphenylethyl-1, 1-diyl) dibenzoic acid and alcohol caused by complex structures of 4, 4'-(2, 2-diphenylethyl-1, 1-diyl) dibenzoic acid and 1, 4-butanediol, the esterification reaction is firstly subjected to branched esterification and then is mixed, so that the yield is increased.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biodegradable polyester polymer material synthesis, and particularly relates to a preparation method of PBAT copolyester material modified by rigid structure of tetraphenyl ethylene. BACKGROUND

[0002] PBAT, also known as polybutylene adipate terephthalate, is one of the most widely used biodegradable materials at present, which has good ductility, elongation at break, heat resistance and impact resistance, and in addition, has excellent biodegradability, and is widely used in plastic packaging film, agricultural mulching film and other film materials. However, its shortcomings are low crystallinity, poor mechanical strength and low elastic modulus.

[0003] In order to overcome the above-mentioned shortcomings, the skilled person in the art attempts to improve the performance of PBAT by physical blending or chemical modification. Among them, chemical modification is to introduce new functional monomers or crosslinking agents to react with PBAT, so as to change its molecular structure and improve its performance. The Chinese patent with the application number CN117820612A discloses a synthesis method of polybutylene adipate terephthalate (PBAT), which solves the problem that the titanium catalyst needs to be modified in advance due to high activity and many side reactions in current production, but the crystallinity and mechanical properties of PBAT material are not improved.

[0004] In recent years, tetraphenyl ethylene, as a functional unit with good rigidity and fluorescence properties, has been widely used in the modification research of high polymer materials. Tetraphenyl ethylene not only can endow the material with unique optical properties, but also can significantly enhance the mechanical properties and thermal stability of the material. In addition, the structure of tetraphenyl ethylene contains a large number of aromatic rings, which can effectively improve the interaction force between polymer chains, and thus optimize the physical properties of the whole system. Therefore, how to introduce tetraphenyl ethylene into the PBAT system for large-scale production has become a problem to be solved. SUMMARY

[0005] In order to solve the technical problem that the modified polybutylene adipate terephthalate prepared by chemical modification cannot improve the crystallinity and mechanical properties of the material mentioned in the background art, the present application provides a preparation method of PBAT copolyester material modified by rigid structure of tetraphenyl ethylene, which improves the elastic modulus and tensile strength of PBAT and expands the use range of the product. The structure general formula of the PBAT copolyester material modified by rigid structure of tetraphenyl ethylene is as follows: The specific technical scheme of the present application is as follows: a preparation method of PBAT copolyester material modified by rigid structure of tetraphenyl ethylene, comprising the following steps: 1) terephthalic acid, 1,4-butanediol and 4,4'-(2,2-diphenyl ethylene-1,1-diyl) benzene dicarboxylic acid are mixed in a molar ratio, a certain amount of catalyst is stirred uniformly and heated, and an esterification reaction intermediate A is obtained by reaction; 2) terephthalic acid, 1,4-butanediol and adipic acid are mixed in a molar ratio, a certain amount of catalyst is stirred uniformly and heated, and an esterification reaction intermediate B is obtained by reaction; 3) esterification reaction intermediate A and esterification reaction intermediate B are mixed and heated to obtain a reaction intermediate; 4) Then continue to warm up, vacuum reduce pressure to 100Pa below to carry out polycondensation reaction, obtain tetraphenyl ethylene rigid structure modified PBAT copolyester.

[0006] Tetraphenyl ethylene is a classic aggregation-induced emission (AIE) molecule, has a rigid structure of spatial stereo-geometry skeleton, simple structure, easy to chemical modification and functionalization, and AIE fluorescent molecules can emit strong fluorescence in the aggregation state of solid powder or thin film, and the structural formula is: In summary, tetraphenyl ethylene is combined with PBAT, which not only improves the mechanical properties, thermal properties and processing properties of PBAT, but also makes the material have certain fluorescence properties as a fluorescent group. The present application introduces a new functional monomer or crosslinking agent to react with PBAT, thereby changing the molecular structure, improving the crystallinity and mechanical properties. Due to the relatively complex structure of 4,4'-(2,2-diphenyl ethylene-1,1-diyl) benzene dicarboxylic acid, the steric hindrance effect will limit the free rotation and movement of the reactants, so the activity of the alcohol reaction is lower than that of terephthalic acid and adipic acid. Therefore, the research team of the present application improves the combination efficiency of 4,4'-(2,2-diphenyl ethylene-1,1-diyl) benzene dicarboxylic acid and 1,4-butanediol by dividing the esterification reaction, and then mixing to improve the yield.

[0007] Further, in step 1), the mass feeding ratio of terephthalic acid, 1,4-butanediol and 4,4'-(2,2-diphenyl ethylene-1,1-diyl) benzene dicarboxylic acid is (20-25):(15-20):(1-1.5).

[0008] Further, in step 2), the mass feeding ratio of terephthalic acid, 1,4-butanediol and adipic acid is (1.2-1.5):(1.5-2.5):(1-1.1).

[0009] Further, in step 1), the heating temperature of esterification is 185-215℃, and the reaction time is 1.5-2h.

[0010] Further, it is characterized in that, in step 2), the heating temperature of esterification is 185-215℃, and the reaction time is 1.5-2h.

[0011] Further, it is characterized in that, in step 3), the heating temperature of mixing is 190-200℃, and the reaction time is 0.5-1h.

[0012] Further, it is characterized in that, in step 3), the feeding ratio of esterification reaction intermediate A and esterification reaction intermediate B is (1-1.2):(1-1.2).

[0013] Further, it is characterized in that, in steps 1) and 2), the catalyst is one or more of titanium-based, antimony-based and germanium-based catalysts.

[0014] As a preference, the reaction catalyst is a titanium compound, one or more of tetrabutyl titanate, tetraisopropyl titanate, tetraethyl titanate, tetramethyl titanate and tetraoctyl titanate.

[0015] As a preference, the reaction catalyst is tetrabutyl titanate.

[0016] Further, it is characterized in that, in steps 1) and 2), the added amount of catalyst is 0.2wt‰-5‰.

[0017] Further, it is characterized in that, in step 4), the temperature of polycondensation reaction is 250-260℃, and the reaction time is 2-2.5h.

[0018] Compared with the prior art, the present application has the following beneficial effects:

[0019] 1) While ensuring the excellent performance of PBAT, the introduction of rigid groups can improve the elastic modulus and tensile strength of PBAT.

[0020] 2) As a classic aggregation-induced emission (AIE) molecule, tetraphenyl ethylene, when polymerized with PBAT, makes the final material have certain fluorescence performance, expanding the application range of the material. DETAILED DESCRIPTION DETAILED DESCRIPTION

[0021] The present application will be further described below in conjunction with examples.

[0022] Example 1 1) Mix terephthalic acid, 1,4-butanediol and 4,4'-(2,2-diphenyl ethylene-1,1-diyl) dibenzoic acid in a molar ratio, add a certain amount of catalyst, stir uniformly and heat, and the reaction obtains esterification reaction intermediate A.

[0023] Specifically, the addition amount of terephthalic acid is 8.3 g, the addition amount of 4,4'-(2,2-diphenylvinyl-1,1-diyl)dibenzoic acid is 0.4 g, and the addition amount of 1,4-butanediol is 6.4 g.

[0024] Specifically, the reaction catalyst is selected as tetrabutyl titanate.

[0025] Specifically, the addition amount of tetrabutyl titanate is 5 mg.

[0026] Specifically, the reaction temperature is 185℃, and the reaction time is 1.5 h.

[0027] 2) Terephthalic acid, 1,4-butanediol and adipic acid are mixed in a molar ratio, a certain amount of catalyst is added, stirred uniformly and heated, and an esterification reaction intermediate B is obtained.

[0028] Specifically, the addition amount of adipic acid is 7.3 g, the addition amount of terephthalic acid is 8.3 g, and the addition amount of 1,4-butanediol is 14.4 g.

[0029] Specifically, the reaction catalyst is selected as tetrabutyl titanate.

[0030] Specifically, the addition amount of tetrabutyl titanate is 10 mg.

[0031] Specifically, the reaction temperature is 185℃, and the reaction time is 1.5 h.

[0032] 3) Esterification reaction intermediate A and esterification reaction intermediate B are mixed and heated to obtain a reaction intermediate.

[0033] Specifically, the reaction temperature is 190℃, and the reaction time is 0.5 h.

[0034] 4) Then continue to heat, vacuumize and reduce the pressure to below 100 Pa to perform a polycondensation reaction, and obtain a tetraphenyl ethylene rigid structure modified PBAT copolyester.

[0035] Specifically, the polycondensation reaction is heated to 250℃.

[0036] Specifically, the duration of the polycondensation reaction is 2 h.

[0037] 5) Performance detection a) Crystallinity test method: the crystallinity of the sample is measured by DSC method, and the sample is scanned at a heating rate of 10℃ / min from 30℃ to 290℃. The crystallinity is the ratio of the heat absorbed by the crystalline part of the polymer melting to the heat absorbed by 100% crystalline polymer melting, but for normal base polyester chips, the crystallinity is very small, and a low-temperature crystallization peak will appear before the melting peak after the glass transition temperature. The heat released by the crystallization during the test should be deducted, then X cCrystallinity is: where: ΔH 0 m is the melting enthalpy of 100% crystalline sample, J / g; ΔH m is the melting enthalpy of the crystallization of the sample determined by DSC, J / g; ΔH c is the heat of crystallization exotherm of the sample during DSC.

[0038] b) Tensile strength, elastic modulus and elongation at break test method: The film samples were tested on a universal material testing machine according to ASTM D-882-18, 5 samples were tested and the average value was taken.

[0039] Comparative Example 1 The difference between this comparative example and Example 1 is that, in this comparative example, no two-way esterification (step 1) and step 2) were carried out, and adipic acid, terephthalic acid, 4,4'-(2,2-diphenylvinyl-1,1-diyl)dibenzoic acid, 1,4-butanediol and catalyst were directly put into the reaction), and the rest of the parameters were the same as Example 1, and the specific steps were as follows: 1) Pretreatment Adipic acid, terephthalic acid, 4,4'-(2,2-diphenylvinyl-1,1-diyl)dibenzoic acid, 1,4-butanediol and catalyst were stirred uniformly according to the weight ratio to obtain the reaction slurry.

[0040] Specifically, the addition amount of adipic acid was 7.3 g, the addition amount of terephthalic acid was 16.6 g, the addition amount of 4,4'-(2,2-diphenylvinyl-1,1-diyl)dibenzoic acid was 0.4 g, and the addition amount of 1,4-butanediol was 20.8 g.

[0041] Specifically, the reaction catalyst was selected as tetrabutyl titanate.

[0042] Specifically, the addition amount of tetrabutyl titanate was 15 mg.

[0043] 2) Esterification reaction The reaction slurry in step 1) was heated to occur esterification reaction, and the esterification reaction intermediate was obtained after the reaction was completed.

[0044] Specifically, the temperature of the esterification reaction was 185°C.

[0045] Specifically, when the amount of water byproduct of the esterification reaction reached 98% of the theoretical water amount, the reaction was considered to be completed.

[0046] 3) Polycondensation reaction Then, the temperature is increased to 190°C for 0.5 h, and a polycondensation reaction is performed under vacuum and reduced pressure to 100 Pa or less to obtain the PBAT copolyester with a rigid structure of tetraphenyl ethylene.

[0047] Specifically, the polycondensation reaction is increased to 250°C.

[0048] Specifically, the polycondensation reaction lasts for 2 h.

[0049] Table 1: Influence of two-path esterification on the properties of the final polybutylene adipate terephthalate material As can be seen from the data in Table 1, when two-path esterification is performed, i.e., all raw materials and catalysts are directly mixed and reacted according to the molar ratio, the material formed has poorer effects in crystallinity, tensile strength, elastic modulus, and elongation at break compared to the effects of the split-path esterification. It is speculated that the reason is that the structure of tetraphenyl ethylene is complex. The relatively complex structure limits the free rotation and movement of the reactants, and thus the activity of the reaction with alcohol is lower than that of terephthalic acid and adipic acid with alcohol.

[0050] Comparative Example 2 The difference between this comparative example and Example 1 is that, in this comparative example, the reaction time of the polycondensation reaction in step 4) is 1 h, and the rest of the process is the same as that of Example 1. The specific steps are as follows: 1) Terephthalic acid, 1,4-butanediol, and 4,4'-(2,2-diphenyl ethylene-1,1-diyl) dibenzoic acid are mixed according to the molar ratio, a certain amount of catalyst is added, stirred uniformly, and heated to obtain an esterification intermediate A.

[0051] Specifically, the addition amount of terephthalic acid is 8.3 g, the addition amount of 4,4'-(2,2-diphenyl ethylene-1,1-diyl) dibenzoic acid is 0.4 g, and the addition amount of 1,4-butanediol is 6.4 g.

[0052] Specifically, the catalyst is tetrabutyl titanate.

[0053] Specifically, the addition amount of tetrabutyl titanate is 5 mg.

[0054] Specifically, the reaction temperature is 185°C, and the reaction time is 1.5 h.

[0055] 2) Terephthalic acid, 1,4-butanediol, and adipic acid are mixed according to the molar ratio, a certain amount of catalyst is added, stirred uniformly, and heated to obtain an esterification intermediate B.

[0056] Specifically, the addition amount of adipic acid is 7.3 g, the addition amount of terephthalic acid is 8.3 g, and the addition amount of 1,4-butanediol is 14.4 g.

[0057] Specifically, the catalyst is selected from tetrabutyl titanate.

[0058] Specifically, the addition amount of tetrabutyl titanate is 10 mg.

[0059] Specifically, the reaction temperature is 185°C, and the reaction time is 1.5 h.

[0060] 3) The esterification reaction intermediates A and B are mixed and heated to obtain a reaction intermediate.

[0061] Specifically, the reaction temperature is 190°C, and the reaction time is 0.5 h.

[0062] 4) Then continue to heat, vacuum and reduce pressure to below 100 Pa to perform a polycondensation reaction to obtain a tetraphenyl ethylene rigid structure modified PBAT copolyester.

[0063] Specifically, the polycondensation reaction is heated to 250°C.

[0064] Specifically, the duration of the polycondensation reaction is 1 h.

[0065] 5) Performance detection The modified polybutylene terephthalate-hexanedioic acid butanediol material synthesized in the present comparative example is detected for tensile strength, crystallinity, elastic modulus, and elongation at break.

[0066] Comparative Example 3 The difference between the present comparative example and Example 1 is that in the present comparative example, in step 14), the reaction time of the polycondensation reaction is 5 h, and the rest of the process is the same as that of Example 1, and the specific steps are as follows: 1) The terephthalic acid, 1,4-butanediol, and 4,4'-(2,2-diphenyl ethylene-1,1-diyl) benzoic acid are mixed in a molar ratio, a certain amount of catalyst is added, stirred uniformly, and heated to obtain an esterification reaction intermediate A.

[0067] Specifically, the addition amount of terephthalic acid is 8.3 g, the addition amount of 4,4'-(2,2-diphenyl ethylene-1,1-diyl) benzoic acid is 0.4 g, and the addition amount of 1,4-butanediol is 6.4 g.

[0068] Specifically, the catalyst is selected from tetrabutyl titanate.

[0069] Specifically, the addition amount of tetrabutyl titanate is 5 mg.

[0070] Specifically, the reaction temperature is 185°C, and the reaction time is 1.5 h.

[0071] 2) p-Phthalic acid, 1,4-butanediol and adipic acid are mixed in a molar ratio, a certain amount of catalyst is added, stirred uniformly and heated, and an esterification reaction intermediate B is obtained.

[0072] Specifically, the addition amount of adipic acid is 7.3 g, the addition amount of p-phthalic acid is 8.3 g, and the addition amount of 1,4-butanediol is 14.4 g.

[0073] Specifically, the catalyst is selected as tetrabutyl titanate.

[0074] Specifically, the addition amount of tetrabutyl titanate is 10 mg.

[0075] Specifically, the reaction temperature is 185°C, and the reaction time is 1.5 h.

[0076] 3) Esterification reaction intermediate A and esterification reaction intermediate B are mixed and heated to obtain a reaction intermediate.

[0077] Specifically, the reaction temperature is 190°C, and the reaction time is 0.5 h.

[0078] 4) Then continue to heat, vacuumize and reduce the pressure to below 100 Pa to perform a polycondensation reaction, and a tetraphenyl ethylene rigid structure modified PBAT copolyester is obtained.

[0079] Specifically, the polycondensation reaction is heated to 250°C.

[0080] Specifically, the duration of the polycondensation reaction is 5 h.

[0081] 5) Performance detection The tensile strength, crystallinity, elastic modulus and elongation at break of the modified polybutylene terephthalate adipate butanediol material synthesized in the present comparative example are detected.

[0082] Table 2 Influence of polycondensation reaction duration on material performance From the data in Table 2, it can be concluded that if the duration of the polycondensation reaction is too high or too low, the tensile strength, crystallinity, elastic modulus and elongation at break of the modified polybutylene terephthalate adipate butanediol material synthesized will decrease, and the reason is speculated to be: when the duration of the polycondensation reaction is too short, the polycondensation reaction is not complete, resulting in low content of polybutylene terephthalate adipate butanediol in the finally formed material and reduced performance; when the duration of the polycondensation reaction is too long, although the molecular weight of the polymer is increased, but with the increase of the polycondensation time, thermal degradation and thermal oxidative degradation of the high molecular also occur, thereby affecting the performance of the material.

[0083] Comparative Example 4 The difference between the present comparative example and example 1 is only that in the present comparative example, the addition amount of 1,4-butanediol in step 1) is 3.0 g, and the rest of the process is the same as that of example 1, and the specific steps are as follows: 1) terephthalic acid, 1,4-butanediol and 4,4'-(2,2-diphenylvinyl-1,1-diyl) benzoic acid were mixed in a molar ratio, a certain amount of catalyst was added and stirred uniformly, and then heated to obtain an esterification reaction intermediate A.

[0084] Specifically, the addition amount of terephthalic acid is 8.3 g, the addition amount of 4,4'-(2,2-diphenylvinyl-1,1-diyl) benzoic acid is 0.4 g, and the addition amount of 1,4-butanediol is 5.5 g.

[0085] Specifically, the catalyst is selected from tetrabutyl titanate.

[0086] Specifically, the addition amount of tetrabutyl titanate is 5 mg.

[0087] Specifically, the reaction temperature is 185°C, and the reaction time is 1.5 h. 2) terephthalic acid, 1,4-butanediol and adipic acid were mixed in a molar ratio, a certain amount of catalyst was added and stirred uniformly, and then heated to obtain an esterification reaction intermediate B.

[0088] Specifically, the addition amount of adipic acid is 7.3 g, the addition amount of terephthalic acid is 8.3 g, and the addition amount of 1,4-butanediol is 14.4 g.

[0089] Specifically, the catalyst is selected from tetrabutyl titanate.

[0090] Specifically, the addition amount of tetrabutyl titanate is 10 mg.

[0091] Specifically, the reaction temperature is 185°C, and the reaction time is 1.5 h.

[0092] 3) The esterification reaction intermediate A and the esterification reaction intermediate B were mixed and heated to obtain a reaction intermediate.

[0093] Specifically, the reaction temperature is 190°C, and the reaction time is 0.5 h.

[0094] 4) Then continue to heat, vacuumize and reduce the pressure to below 100 Pa to perform a polycondensation reaction to obtain a tetraphenylvinyl rigid structure modified PBAT copolyester.

[0095] Specifically, the polycondensation reaction is heated to 250°C.

[0096] Specifically, the duration of the polycondensation reaction is 2 h.

[0097] 5) Performance detection The modified polybutylene terephthalate-hexanedioate butanediol material synthesized in the present comparative example was detected for tensile strength, crystallinity, elastic modulus and elongation at break.

[0098] Comparative Example 5 The present comparative example differs from Example 1 only in that in the present comparative example, in step 1), the addition amount of 1,4-butanediol is 20.0 g, and the rest of the process is the same as that of Example 1, and the specific steps are as follows: 1) Mix terephthalic acid, 1,4-butanediol and 4,4'-(2,2-diphenylvinyl-1,1-diyl) benzoic acid in a molar ratio, add a certain amount of catalyst, stir uniformly and heat, and obtain esterification intermediate A.

[0099] Specifically, the addition amount of terephthalic acid is 8.3 g, the addition amount of 4,4'-(2,2-diphenylvinyl-1,1-diyl) benzoic acid is 0.4 g, and the addition amount of 1,4-butanediol is 13.7 g.

[0100] Specifically, the catalyst is selected to be tetrabutyl titanate.

[0101] Specifically, the addition amount of tetrabutyl titanate is 5 mg.

[0102] Specifically, the reaction temperature is 185°C, and the reaction time is 1.5 h 2) Mix terephthalic acid, 1,4-butanediol and adipic acid in a molar ratio, add a certain amount of catalyst, stir uniformly and heat, and obtain esterification intermediate B.

[0103] Specifically, the addition amount of adipic acid is 7.3 g, the addition amount of terephthalic acid is 8.3 g, and the addition amount of 1,4-butanediol is 14.4 g.

[0104] Specifically, the catalyst is selected to be tetrabutyl titanate.

[0105] Specifically, the addition amount of tetrabutyl titanate is 10 mg.

[0106] Specifically, the reaction temperature is 185°C, and the reaction time is 1.5 h.

[0107] 3) Mix esterification intermediate A and esterification intermediate B and heat to obtain a reaction intermediate.

[0108] Specifically, the reaction temperature is 190°C, and the reaction time is 0.5 h.

[0109] 4) Then continue to heat, vacuumize and reduce the pressure to below 100 Pa to perform a polycondensation reaction, and obtain a tetraphenylvinyl rigid structure modified PBAT copolyester.

[0110] Specifically, the polycondensation reaction is heated to 250°C.

[0111] Specifically, the condensation reaction duration is 2 h.

[0112] 4) Performance detection The tensile strength, crystallinity, elastic modulus, and elongation at break of the modified polybutylene terephthalate-hexanedioate material synthesized in the present comparative example were detected.

[0113] Table 31, Effect of the addition amount of 1,4-butanediol on the performance of the finally formed material From the data in Table 3, we can conclude that when the addition amount of 1,4-butanediol in step 1) is too high or too low, the performance (crystallinity, tensile strength, elastic modulus, and elongation at break) of the finally formed polybutylene terephthalate-hexanedioate material will decrease, which is presumably due to the fact that when the addition amount of 1,4-butanediol in step 1) is too low, the 4,4'-(2,2-diphenylvinyl-1,1-diyl)dibenzoic acid does not react completely; when the addition amount of 1,4-butanediol in step 1) is too high, the probability of the esterification reaction between terephthalic acid and 1,4-butanediol increases, and the probability of the mutual reaction between 4,4'-(2,2-diphenylvinyl-1,1-diyl)dibenzoic acid and 1,4-butanediol decreases.

[0114] Example 2 1) Terephthalic acid, 1,4-butanediol, and 4,4'-(2,2-diphenylvinyl-1,1-diyl)dibenzoic acid were mixed in a molar ratio, a certain amount of catalyst was added, stirred uniformly, and heated to obtain an esterification reaction intermediate A.

[0115] Specifically, the addition amount of terephthalic acid was 8.3 g, the addition amount of 4,4'-(2,2-diphenylvinyl-1,1-diyl)dibenzoic acid was 0.4 g, and the addition amount of 1,4-butanediol was 6.4 g.

[0116] Specifically, the reaction catalyst was selected to be tetraethyl titanate.

[0117] Specifically, the addition amount of tetraethyl titanate was 5 mg.

[0118] Specifically, the reaction temperature was 205°C, and the reaction time was 1.5 h.

[0119] 2) Terephthalic acid, 1,4-butanediol, and hexanedioic acid were mixed in a molar ratio, a certain amount of catalyst was added, stirred uniformly, and heated to obtain an esterification reaction intermediate B.

[0120] Specifically, the addition amount of hexanedioic acid was 7.3 g, the addition amount of terephthalic acid was 8.3 g, and the addition amount of 1,4-butanediol was 14.4 g.

[0121] Specifically, the reaction catalyst is selected as tetraethyl titanate.

[0122] Specifically, the addition amount of tetraethyl titanate is 10 mg.

[0123] Specifically, the reaction temperature is 185°C, and the reaction time is 1.5 h.

[0124] 3) The esterification reaction intermediates A and B are mixed and heated to obtain a reaction intermediate.

[0125] Specifically, the reaction temperature is 193°C, and the reaction time is 0.5 h.

[0126] 4) Then, the temperature is continuously increased, and the polycondensation reaction is carried out under vacuum and reduced pressure to 100 Pa or less to obtain a tetraphenyl ethylene rigid structure modified PBAT copolyester.

[0127] Specifically, the polycondensation reaction is heated to 250°C.

[0128] Specifically, the duration of the polycondensation reaction is 2 h.

[0129] 5) Performance detection The tensile strength, crystallinity, elastic modulus, and elongation at break of the modified polybutylene terephthalate-hexanedioic acid butanediol material synthesized in the comparative example are detected.

[0130] Example 3 1) The terephthalic acid, 1,4-butanediol, and 4,4'-(2,2-diphenyl ethylene-1,1-diyl) benzoic acid are mixed in a molar ratio, a certain amount of catalyst is added and stirred uniformly, and then heated to obtain an esterification reaction intermediate A.

[0131] Specifically, the addition amount of terephthalic acid is 8.3 g, the addition amount of 4,4'-(2,2-diphenyl ethylene-1,1-diyl) benzoic acid is 0.4 g, and the addition amount of 1,4-butanediol is 6.4 g.

[0132] Specifically, the reaction catalyst is selected as tetraisopropyl titanate.

[0133] Specifically, the addition amount of tetraisopropyl titanate is 5 mg.

[0134] Specifically, the reaction temperature is 215°C, and the reaction time is 2 h.

[0135] 2) The terephthalic acid, 1,4-butanediol, and adipic acid are mixed in a molar ratio, a certain amount of catalyst is added and stirred uniformly, and then heated to obtain an esterification reaction intermediate B.

[0136] Specifically, the addition amount of adipic acid is 7.3 g, the addition amount of terephthalic acid is 8.3 g, and the addition amount of 1,4-butanediol is 14.4 g.

[0137] Specifically, the reaction catalyst is selected as tetraisopropyl titanate.

[0138] Specifically, the addition amount of tetraisopropyl titanate is 10 mg.

[0139] Specifically, the reaction temperature is 190 DEG C, and the reaction time is 2 h.

[0140] 3) The esterification reaction intermediates A and B are mixed and heated to obtain a reaction intermediate.

[0141] Specifically, the reaction temperature is 190 DEG C, and the reaction time is 0.5 h.

[0142] 4) Then, the temperature is continuously increased, and the polycondensation reaction is carried out under vacuum and reduced pressure to 100 Pa or less to obtain a tetraphenyl ethylene rigid structure modified PBAT copolyester.

[0143] Specifically, the polycondensation reaction is heated to 250 DEG C.

[0144] Specifically, the duration of the polycondensation reaction is 2 h.

[0145] 5) Performance detection The tensile strength, crystallinity, elastic modulus and elongation at break of the modified polybutylene terephthalate-hexanedioic acid butanediol material synthesized in the present comparative example are detected.

[0146] The raw materials and equipment used in the present application are conventional raw materials and equipment in the art, unless otherwise specified; the methods used in the present application are conventional methods in the art, unless otherwise specified.

[0147] The above is only a preferred embodiment of the present application, and does not limit the present application in any way. Any simple modification, change and equivalent transformation of the above embodiment based on the technical essence of the present application are still within the protection scope of the technical solution of the present application.

Claims

1. A method for preparing a PBAT copolyester material with rigid structure modified tetraphenyl ethylene, characterized in that, Comprising the following steps: 1) terephthalic acid, 1,4-butanediol and 4,4'-(2,2-diphenyl ethylene-1,1-diyl) benzoic acid are mixed in a molar ratio, a catalyst is added and stirred uniformly, and then heated to obtain an esterification reaction intermediate A; 2) terephthalic acid, 1,4-butanediol and adipic acid are mixed in a molar ratio, a catalyst is added and stirred uniformly, and then heated to obtain an esterification reaction intermediate B; 3) the esterification reaction intermediate A and the esterification reaction intermediate B are mixed and heated to obtain a reaction intermediate; 4) a polycondensation reaction is carried out after warming and vacuum reduction, to obtain a tetraphenyl ethylene rigid structure modified PBAT copolyester.

2. The method of claim 1, wherein the PBAT copolyester material is prepared by modifying the rigid structure of a tetraphenyl ethylene. In step 1), the mass feeding ratio of terephthalic acid, 1,4-butanediol and 4,4'-(2,2-diphenyl ethylene-1,1-diyl) benzoic acid is: (20-25): (15-20): (1-1.5). ​ 3. The method for preparing a PBAT copolyester material with rigid structure modified by tetraphenyl ethylene according to claim 1 or 2, characterized in that, In step 2), the mass feeding ratio of terephthalic acid, 1,4-butanediol and adipic acid is: (1.2-1.5): (1.5-2.5): (1-1.1).

4. The method for preparing a PBAT copolyester material with a rigid structure modified by tetraphenyl ethylene according to claim 1, characterized in that, In step 1), the heating temperature of the esterification is 185 ℃-215 ℃, and the reaction time is 1.5-2h.

5. The method for preparing a tetraphenylethylene rigid structure modified PBAT copolyester material according to claim 1, characterized in that, In step 2), the heating temperature of the esterification is 185 ℃-215 ℃, and the reaction time is 1.5-2h.

6. The method of claim 1, wherein the PBAT copolyester material is prepared by modifying the rigid structure of tetraphenyl ethylene. In step 3), the temperature of the mixed heating is 190-200℃, and the reaction time is 0.5-1h.

7. The method of claim 1, wherein the PBAT copolyester material is prepared by modifying the rigid structure of tetraphenyl ethylene. In step 3), the feeding ratio of the esterification reaction intermediate A and the esterification reaction intermediate B is: (1-1.2): (1-1.2).

8. The method for preparing a tetraphenylethylene rigid structure modified PBAT copolyester material according to claim 1, characterized in that, In steps 1) and 2), the catalyst is one or more of titanium, antimony and germanium catalysts.

9. The method for preparing a PBAT copolyester material with rigid structure modified by tetraphenyl ethylene according to claim 1 or 8, characterized in that, In steps 1) and 2), the addition amount of the catalyst is 0.2‰-0.5‰ of the total mass of the terephthalic acid, adipic acid and 4,4'-(2,2-diphenyl ethylene-1,1-diyl) benzoic acid.

10. The method of claim 1, wherein the PBAT copolyester material is prepared by modifying the rigid structure of tetraphenyl ethylene. In step 4), the temperature of the polycondensation reaction is 250-260℃, the reaction time is 2-2.5h, and the vacuum degree is ≤100 Pa.

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