阅读说明：本技术 一种高耐热性可降解共聚酯及其制备方法 (High-heat-resistance degradable copolyester and preparation method thereof ) 是由 徐志玉 王松林 徐锦龙 吴海强 欧阳杰 于 2020-07-07 设计创作，主要内容包括：本发明涉及共聚酯技术领域,公开了一种高耐热性可降解共聚酯及其制备方法。该高耐热性可降解共聚酯包括以下原料：芳香族二元酸,脂肪族二元醇,聚乙二醇,POSS衍生物；所述POSS衍生物中,其中一个Si原子上连接有至少一个苯基和至少两个酯基。本发明通过引入第三单体对共聚酯的结构与成分进行调控,改善了传统聚酯的疏水问题,有效的提高了共聚酯的可降解性；通过将POSS衍生物引入共聚酯主链中,能有效提高共聚酯的耐热性和可降解性,解决了可降解共聚酯不耐热的问题；POSS衍生物中的苯基有助于进一步提高共聚酯的耐热性。(The invention relates to the technical field of copolyester, and discloses high-heat-resistance degradable copolyester and a preparation method thereof. The high-heat-resistance degradable copolyester comprises the following raw materials: aromatic dibasic acid, aliphatic dihydric alcohol, polyethylene glycol and POSS derivative; in the POSS derivative, at least one phenyl and at least two ester groups are connected to one Si atom. According to the invention, the structure and components of the copolyester are regulated and controlled by introducing the third monomer, so that the hydrophobic problem of the traditional polyester is improved, and the degradability of the copolyester is effectively improved; by introducing the POSS derivative into the main chain of the copolyester, the heat resistance and the degradability of the copolyester can be effectively improved, and the problem that the degradable copolyester is not heat-resistant is solved; the phenyl group in the POSS derivative contributes to further improving the heat resistance of the copolyester.)

1. The high-heat-resistance degradable copolyester is characterized by comprising the following raw materials: aromatic dibasic acid, aliphatic dihydric alcohol, polyethylene glycol and POSS derivative; in the POSS derivative, at least one phenyl and at least two ester groups are connected to one Si atom.

2. The high heat resistant degradable copolyester of claim 1, wherein the POSS derivative is prepared by the following steps:

(a) dissolving phenyl isobutyl-POSS into dichloromethane in an ice water bath to prepare dichloromethane solution of the phenyl isobutyl-POSS; dissolving ICl into dichloromethane under the condition of keeping out of the sun to prepare a dichloromethane solution of ICl; dropwise adding a dichloromethane solution of ICl into a dichloromethane solution of phenyl isobutyl-POSS in an ice water bath, reacting for 7-9 h, and then transferring to a temperature of 20-30 ℃ for reaction for 20-24 h; after the reaction is finished, washing off excessive ICl by using a saturated sodium sulfite solution, extracting an organic layer by using dichloromethane, washing by using saturated saline solution, drying by using anhydrous sodium sulfate, filtering and carrying out rotary evaporation to obtain a white solid, namely iodophenyl heptaisobutyl full-condensation POSS;

(b) dissolving iodophenyl heptaisobutyl full-condensation POSS prepared in the step (a), 4-aminophenylboronic acid, a Suzuki coupling reaction catalyst and an alkali assistant in an organic solvent, and reacting at 90-100 ℃ for 6-8 h; after the reaction is finished, obtaining a Suzuki coupling reaction product through extraction and rotary evaporation;

(c) dissolving the Suzuki coupling reaction product obtained in the step (b) and acrylic ester in an organic solvent, and reacting at 20-25 ℃ for 70-75 h; and after the reaction is finished, distilling and purifying the solution to obtain the POSS derivative.

3. The high heat resistant degradable copolyester according to claim 1, wherein:

the weight of the POSS derivative is 2-5 wt% of the total weight of the aromatic dibasic acid; and/or

The mole number of the polyethylene glycol is 0.05-0.2% of that of the aromatic dibasic acid.

4. The high heat resistant degradable copolyester according to claim 1, wherein:

the polyethylene glycol is one of PEG-2000, PEG-4000 and PEG-6000; and/or

The aromatic dibasic acid is one of terephthalic acid, biphenyldicarboxylic acid and 1, 4-naphthalenedicarboxylic acid; and/or

The aliphatic diol is one of ethylene glycol, 1, 3-propylene glycol, 1, 4-butanediol, 1, 4-cyclohexanedimethanol and 1, 6-hexanediol.

5. The high heat resistant degradable copolyester of claim 2, wherein in the step (a), the molar ratio of the phenyl isobutyl-POSS to the ICl is 1.5-2.

6. The high heat resistant degradable copolyester according to claim 2, wherein:

in the step (b), the molar ratio of the iodophenyl heptaisobutyl full-condensed POSS to the 4-aminophenylboronic acid is 1: 1.2-2; and/or

In the step (b), the molar ratio of the iodophenyl heptaisobutyl fully condensed POSS to the Suzuki coupling reaction catalyst is 1: 0.01-0.03; and/or

In the step (b), the molar ratio of the iodophenyl heptaisobutyl full-condensed POSS to the alkali assistant is 1: 1.5-2.5.

7. The high heat resistant degradable copolyester of claim 2, wherein in the step (c), the molar ratio of the Suzuki coupling reaction product to the acrylate is 1: 1.5-2.

8. The high heat resistant degradable copolyester according to claim 2, wherein:

in the step (b), the catalyst for the Suzuki coupling reaction is tetrakis (triphenylphosphine) palladium; and/or

In the step (b), the alkali assistant is potassium carbonate; and/or

In the step (b), the organic solvent is one or more of dichloromethane, 1, 2-dichloroethane, 1, 4-dioxane and DMF; and/or

In the step (c), the acrylate is one or more of methyl acrylate, ethyl acrylate and hydroxyethyl acrylate; and/or

In the step (c), the organic solvent is one or more of tetrahydrofuran, dichloromethane, 1, 2-dichloroethane, 1, 4-dioxane and acetone.

9. A method for preparing the high heat resistant degradable copolyester as claimed in any one of claims 1 to 8, which comprises the steps of: adding aromatic dibasic acid, aliphatic dihydric alcohol and an esterification reaction catalyst into a reaction container to carry out esterification reaction; and after the esterification water yield reaches 95-97% of the theoretical water yield, adding a POSS derivative and polyethylene glycol for polycondensation reaction to obtain the high-heat-resistance degradable copolyester.

10. The process of claim 9, wherein the esterification catalyst is one or more of tetrabutyl titanate, ethylene glycol antimony, or antimony trioxide.

Technical Field

The invention relates to the technical field of copolyester, in particular to high-heat-resistance degradable copolyester and a preparation method thereof.

Background

Polyester materials are mainly polyethylene terephthalate (PET), and are widely used in the fields of textiles, food, packaging, medicine, information, electronics, and the like. But the environment is harmed because the environment can exist stably for a long time in nature, the environment is a main component of environment white pollution, and the negative influence on the environment is aggravated along with the rapid development of the industry. Therefore, the development of a material with excellent properties and degradability to replace the conventional polyester is one of the important approaches to solve the problem.

The important basis for polyester degradation is hydrophilicity, and the degradation process is also a hydrolysis process. Because the traditional polyester material has regular chain structure and hydrophobic property, the degradation process is limited by molecular chain activity and crystal region penetrability, and the traditional polyester material is difficult to hydrolyze under natural conditions. The traditional polyester components are designed and structurally adjusted by adding a third monomer, so that the degradability of the polyester is improved on the premise of not influencing the wearability. The aliphatic polyethylene glycol has a flexible hydrophilic chain, is a polymer with excellent hydrophilic performance, can be used as a third monomer block in a PET macromolecular chain segment, improves the hydrophilicity and crystallinity of copolyester, and prepares degradable polyester, however, the degradable polyester added with the third monomer has poor thermal stability due to the common special structure of the macromolecular chain. For example, chinese patent publication No. CN102924701A discloses a hydrophilic polyester and a preparation method thereof, wherein PEG is added in the second esterification stage to prepare a hydrophilic polyester, but due to the introduction of hydrophilic group-OH, the glass transition temperature of the copolyester is lowered, so that the heat resistance of the polyester is lowered, the thermal stability is poor, and this disadvantage does not satisfy the administration function of the degradable copolyester, and limits the marketable popularization and use thereof, so it is very practical to develop a degradable copolyester with high thermal stability.

Polyhedral oligomeric silsesquioxanes (POSS) with Si₈O₁₂The inorganic rigid core is surrounded by eight organic substituents (R groups) connected with Si top points, the inorganic core gives good heat resistance and mechanical property to the material, and the organic groups on the periphery can improve good chemical compatibility between POSS and polymer. Therefore, POSS and derivatives thereof can be introduced into polymers as nanoparticle additives in order to improve the modulus, strength and vitrification of the polymersTemperature, mechanical properties, thermal stability and the like.

Chinese patent publication No. CN102924701A discloses a preparation method of a degradable organic-inorganic nano hybrid material containing POSS, comprising the following steps: (1) firstly, amino POSS and hydroxyethyl acrylate are subjected to Michael addition reaction to prepare a bifunctional POSS derivative; (2) then, carrying out esterification reaction on aromatic dibasic acid and aliphatic dihydric alcohol to form an esterified product, and carrying out melt polycondensation reaction on the POSS derivative containing the bifunctional group, the aliphatic hydroxy acid oligomer and the esterified product to obtain the degradable organic-inorganic nano hybrid material containing the POSS. The method grafts the cage structure on the polyester molecular chain through chemical copolymerization, and POSS is dispersed evenly in the hybrid material and is not easy to agglomerate in the preparation process, thereby improving the degradation performance of the copolyester, but the R group in the bifunctional POSS derivative contains- (CH)₂)₃The copolyester cannot be effectively crosslinked with macromolecular chains of the copolymer, so that the copolyester has low heat resistance and is limited to use in some special occasions.

Disclosure of Invention

In order to solve the technical problems, the invention provides high-heat-resistance degradable copolyester and a preparation method thereof. By introducing POSS derivatives with specific structures, the copolyester disclosed by the invention has degradability and better heat resistance.

The specific technical scheme of the invention is as follows:

a high heat-resistant degradable copolyester comprises the following raw materials: aromatic dibasic acid, aliphatic dihydric alcohol, polyethylene glycol and POSS derivative; in the POSS derivative, at least one phenyl and at least two ester groups are connected to one Si atom.

According to the invention, the third monomer polyethylene glycol is introduced into the polyester to form the copolyester, so that the hydrophilicity of the copolyester is increased, the entrance of water molecules is facilitated, and the degradation performance of the copolyester is improved.

The invention solves the problem of the heat resistance reduction of the degradable copolyester by introducing the POSS derivative with a specific structure: the POSS derivative is blocked in a copolyester main chain through ester exchange reaction between two ester groups and carboxyl in aromatic dibasic acid or hydroxyl in aliphatic dihydric alcohol, and a cage-shaped structure in the POSS derivative is grafted to the copolyester, so that the compatibility between the POSS derivative and the copolyester can be effectively improved, the POSS derivative has better dispersibility, and agglomeration is prevented, and the POSS derivative has a better effect of improving the heat resistance of the copolyester; meanwhile, the POSS derivative is blocked in the main chain of the copolyester, so that the POSS derivative can be used as an additive to change the regular arrangement in the macromolecular chain of the copolyester, increase the amorphous region of the copolyester and further improve the degradability of the copolyester. In addition, the phenyl group has higher rigidity, can further improve the glass transition temperature of the copolyester, and is beneficial to improving the heat resistance of the copolyester.

Preferably, the POSS derivatives are prepared by the following process:

(a) dissolving phenyl isobutyl-POSS into dichloromethane in an ice water bath to prepare dichloromethane solution of the phenyl isobutyl-POSS; dissolving ICl into dichloromethane under the condition of keeping out of the sun to prepare a dichloromethane solution of ICl; dropwise adding a dichloromethane solution of ICl into a dichloromethane solution of phenyl isobutyl-POSS in an ice water bath, reacting for 7-9 h, and then transferring to a temperature of 20-30 ℃ for reacting for 20-24 h; after the reaction is finished, washing off excessive ICl by using a saturated sodium sulfite solution, extracting an organic layer by using dichloromethane, washing by using saturated saline solution, drying by using anhydrous sodium sulfate, filtering and carrying out rotary evaporation to obtain a white solid, namely iodophenyl heptaisobutyl full condensation POSS;

(b) dissolving iodophenyl heptaisobutyl full-condensation POSS prepared in the step (a), 4-aminophenylboronic acid, a Suzuki coupling reaction catalyst and an alkali assistant in an organic solvent, and reacting at 90-100 ℃ for 6-8 h; after the reaction is finished, obtaining a Suzuki coupling reaction product through extraction and rotary evaporation;

(c) dissolving the Suzuki coupling reaction product obtained in the step (b) and acrylic ester in an organic solvent, and reacting at 20-25 ℃ for 70-75 h; and after the reaction is finished, distilling and purifying the solution to obtain the POSS derivative.

In phenyl isobutyl-POSS (phenylisobutyl POSS), Si₈O₁₂Eight organic substituents connected with Si top points on the periphery of the inorganic rigid inner core are a phenyl group and seven isobutyl groups, and the structural formula of the organic substituents is as follows:

in the step (a), a substitution reaction is carried out between phenyl isobutyl-POSS and ICl, and H on a benzene ring is substituted by I. In the step (b), Suzuki coupling reaction is carried out between iodophenyl heptaisobutyl full condensation-POSS and 4-aminophenylboronic acid. In the step (c), amino in the Suzuki coupling reaction product and a carbon-carbon double bond in the acrylate carry out Michael addition reaction, and the generated imino continues to carry out Michael addition reaction with a carbon-carbon double bond in another molecule of acrylate. In the POSS derivative finally obtained, the R groups (organic substituent groups connected with Si top points) connected on seven Si atoms are isobutyl groups, and the R group connected on another Si atom has the following structure: one N atom being linked to the Si atom by two phenyl groups, to which N atom there are also attached two-CH groups₂CH₂COO-。

The POSS derivative takes part in the synthesis of the copolyester main chain through the ester exchange reaction between two ester groups and hydroxyl in aliphatic diol, so that the dispersity of the POSS derivative can be effectively improved, the agglomeration is prevented, and the heat resistance and the degradability of the copolyester are improved. The N atom is connected with the Si atom through two phenyl groups, so that the connection between a cage structure part in the POSS derivative and the copolyester main chain has higher rigidity, the glass transition temperature of the copolyester is improved, and the copolyester has better heat resistance.

Preferably, the weight of the POSS derivative is 2-5 wt% of the total weight of the aromatic dibasic acid.

Preferably, the number of moles of the polyethylene glycol is 0.05 to 0.2% of the number of moles of the aromatic dibasic acid.

Preferably, the polyethylene glycol is one of PEG-2000, PEG-4000 and PEG-6000.

Preferably, the aromatic dibasic acid is one of terephthalic acid, biphenyldicarboxylic acid and 1, 4-naphthalenedicarboxylic acid.

Preferably, the aliphatic diol is one of ethylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 4-cyclohexanedimethanol, and 1, 6-hexanediol.

Preferably, in the step (a), the molar ratio of the phenyl isobutyl-POSS to the ICl is 1.5-2.

Preferably, in the step (b), the molar ratio of the iodophenyl heptaisobutyl full-condensed POSS to the 4-aminophenylboronic acid is 1: 1.2-2.

Preferably, in the step (b), the molar ratio of the iodophenyl heptaisobutyl fully condensed POSS to the Suzuki coupling reaction catalyst is 1: 0.01-0.03.

Preferably, in the step (b), the molar ratio of the iodophenyl heptaisobutyl fully condensed POSS to the alkali assistant is 1: 1.5-2.5.

Preferably, in the step (b), the mass ratio of the total mass of the iodophenyl heptaisobutyl full-condensation POSS, the 4-aminophenylboronic acid, the Suzuki coupling reaction catalyst and the alkali assistant to the mass of the organic solvent is 1: 5-10.

Preferably, in the step (c), the molar ratio of the Suzuki coupling reaction product to the acrylate is 1: 1.5-2.

Preferably, in the step (c), the ratio of the total mass of the Suzuki coupling reaction product and the acrylate to the mass of the organic solvent is 1: 10-20.

Preferably, in step (b), the Suzuki coupling reaction catalyst is tetrakis (triphenylphosphine) palladium.

Preferably, in step (b), the alkali assistant is potassium carbonate.

Preferably, in step (b), the organic solvent is one or more of dichloromethane, 1, 2-dichloroethane, 1, 4-dioxane and DMF.

Preferably, in the step (c), the acrylate is one or more of methyl acrylate, ethyl acrylate and hydroxyethyl acrylate; and/or

Preferably, in step (c), the organic solvent is one or more of tetrahydrofuran, dichloromethane, 1, 2-dichloroethane, 1, 4-dioxane and acetone.

A method for preparing the high heat-resistant degradable copolyester comprises the following steps: adding aromatic dibasic acid, aliphatic dihydric alcohol and an esterification reaction catalyst into a reaction vessel for esterification reaction; and after the esterification water yield reaches 95-97% of the theoretical water yield, adding POSS derivative and polyethylene glycol for polycondensation reaction to obtain the high-heat-resistance degradable copolyester.

Preferably, the esterification reaction catalyst is one or more of tetrabutyl titanate, ethylene glycol antimony or antimony trioxide.

Compared with the prior art, the invention has the following advantages:

(1) the structure and components of the copolyester are regulated and controlled by introducing a third monomer, so that the hydrophobic problem of the traditional polyester is improved, and the degradability of the copolyester is effectively improved;

(2) by introducing the POSS derivative into the main chain of the copolyester, the heat resistance and the degradability of the copolyester can be effectively improved, and the problem that the degradable copolyester is not heat-resistant is solved; the phenyl in the POSS derivative contributes to further improving the heat resistance of the copolyester; the improvement of the heat resistance can effectively overcome the application defect of the degradable copolyester, so that the degradable copolyester can be applied to the fields of heat-resistant films, hot-filling polyester bottles, light automobile tail pipe and the like;

(3) the preparation process is simple, the functionalized polyester production can be realized on the basis of the traditional polyester production by carrying out the on-line modifier adding structural design on the second esterification stage in the traditional five-kettle polyester production process, the investment is low, and the method is suitable for industrial large-scale production.

Drawings

FIG. 1 is a DSC comparison of the copolyester prepared in example 1 (PET-PEG-POSS) with the copolyester prepared in comparative example 1 (PET-PEG);

FIG. 2 is a graph of the water contact angle of the copolyester prepared in example 1 (after modification) and the copolyester prepared in comparative example 3 (before modification); FIG. 3 is a graph showing the degradation rate of the copolyester prepared in example 1 in an in-soil test.

Detailed Description

The present invention will be further described with reference to the following examples.

General examples

Preparing high-heat-resistance degradable copolyester by the following steps:

(1) preparation of POSS derivatives:

(1.1) dissolving phenyl isobutyl-POSS into dichloromethane in an ice-water bath to prepare a dichloromethane solution of the phenyl isobutyl-POSS; dissolving ICl into dichloromethane under the condition of keeping out of the sun to prepare a dichloromethane solution of ICl; dropwise adding a dichloromethane solution of ICl into a dichloromethane solution of phenyl isobutyl-POSS in an ice water bath, reacting for 7-9 h, and then transferring to a temperature of 20-30 ℃ for reacting for 20-24 h; after the reaction is finished, washing off excessive ICl by using a saturated sodium sulfite solution, extracting an organic layer by using dichloromethane, washing by using saturated saline solution, drying by using anhydrous sodium sulfate, filtering and carrying out rotary evaporation to obtain a white solid, namely iodophenyl heptaisobutyl full condensation POSS;

the molar ratio of the phenyl isobutyl-POSS to the ICl is 1.5-2;

(1.2) dissolving iodophenyl heptaisobutyl full-condensation POSS prepared in the step (1.1), 4-aminophenylboronic acid, a Suzuki coupling reaction catalyst and an alkali assistant in an organic solvent, and reacting for 6-8 hours at 90-100 ℃; after the reaction is finished, obtaining a Suzuki coupling reaction product through extraction and rotary evaporation;

the catalyst for the Suzuki coupling reaction is tetrakis (triphenylphosphine) palladium; the alkali assistant is potassium carbonate; the organic solvent is one or more of dichloromethane, 1, 2-dichloroethane, 1, 4-dioxane and DMF; the molar ratio of the iodophenyl heptaisobutyl full-condensed POSS to the 4-aminophenylboronic acid is 1: 1.2-2; the molar ratio of the iodophenyl heptaisobutyl fully-condensed POSS to the Suzuki coupling reaction catalyst is 1: 0.01-0.03; the molar ratio of the iodophenyl heptaisobutyl fully condensed POSS to the alkali assistant is 1: 1.5-2.5; the mass ratio of the total mass of the iodophenyl heptaisobutyl full-condensation POSS, the 4-aminophenylboronic acid, the Suzuki coupling reaction catalyst and the alkali assistant to the mass of the organic solvent is 1: 5-10;

(1.3) dissolving the product of the Suzuki coupling reaction obtained in the step (1.2) and acrylic ester in an organic solvent, and reacting at 20-25 ℃ for 70-75 h; after the reaction is finished, distilling and purifying the solution to obtain the POSS derivative;

the acrylate is one or more of methyl acrylate, ethyl acrylate and hydroxyethyl acrylate; the organic solvent is one or more of tetrahydrofuran, dichloromethane, 1, 2-dichloroethane, 1, 4-dioxane and acetone; the molar ratio of the Suzuki coupling reaction product to the acrylate is 1: 1.5-2; the mass ratio of the total mass of the Suzuki coupling reaction product and the acrylic ester to the organic solvent is 1: 10-20;

(2) preparing copolyester:

(2.1) adding aromatic dibasic acid, aliphatic dihydric alcohol and an esterification reaction catalyst into a reaction vessel for esterification reaction; the esterification catalyst is one or more of tetrabutyl titanate, ethylene glycol antimony or antimony trioxide;

and (2.2) after the esterification water yield reaches 95-97% of the theoretical water yield, adding the POSS derivative and the polyethylene glycol obtained in the step (1) to perform polycondensation reaction, thus obtaining the high-heat-resistance degradable copolyester.