Preparation method of full-bio-based PBAT polyester

Abstract

The invention provides a method for preparing PBAT polyester from full bio-based source monomers, the three monomers adipic acid, terephthalic acid and 1, 4-butanediol are all synthesized from biomass raw materials, and the method comprises the following steps: under the protection of inert atmosphere, adding adipic acid, terephthalic acid, 1, 4-butanediol and a catalyst into a reactor, and reacting at 180-220 DEG C for 1-2 hours to obtain the PBAT polyester. Reacting at normal pressure for 2-8 hours; heating to 230-250 DEG C, carrying out polycondensation reaction for 3-8 hours, vacuumizing by using a vacuum pump, and removing small molecule byproducts generated in the reaction, so as to obtain a PBAT crude product after the polycondensation reaction is finished; and adding an organic solvent into the PBAT crude product to completely dissolve the PBAT crude product, then adding alcohol to generate a precipitate, and filtering and drying the precipitate to obtain the full-bio-based PBAT polyester. The synthesis process is simple and easy to implement. The mechanical property of the finally obtained PBAT polyester can be comparable with that of petroleum-based PBAT. And all the raw materials do not depend on fossil resources, so that the method is environment-friendly and has a good application prospect.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of high molecular polymer materials and chemical industry, and relates to a preparation method of a PBAT polyester material synthesized from full-bio-based monomers and having good mechanical properties. BACKGROUND

[0002] The emergence of plastics has brought great convenience to people's daily life. However, most plastics have a degradation period of hundreds of years in nature, causing serious environmental pollution. In order to solve the problem of "white pollution", research and development of biodegradable materials have become an important coping strategy. Polybutylene adipate terephthalate (PBAT) is a biodegradable polymer with good flexibility, impact resistance and thermal stability, and has been widely used in biodegradable packaging materials. However, its synthesis mainly relies on petroleum-based monomers, which still causes environmental pollution to some extent. Therefore, more and more attention has been paid to the development of full-bio-based biodegradable polymers using biomass resources as raw materials, which can be used as environmentally friendly substitutes for petroleum-based plastics and have good application prospects.

[0003] Currently, there have been reports on the preparation of bio-based polyesters using biomass resources as raw materials. For example, a bio-based phenolic resin and a preparation method thereof are disclosed in Chinese Patent Application No. 20110163338.5, which uses bio-based monomers 2,5-dimethylfuran and phenol as raw materials to prepare a new type of phenolic resin. Chinese Patent Application No. 201210258520.3 discloses a bio-based polyarylate and a preparation method thereof, which uses 2,5-furan dicarboxylic acid and bisphenol acid to prepare the corresponding product by esterification. However, the bio-based polyesters prepared by the above methods are not fully bio-based in terms of raw materials, and some raw materials still come from petroleum-based sources. The full-bio-based monomers used to synthesize PBAT polyesters developed in the present application have important scientific significance and application value. SUMMARY

[0004] In order to overcome the problems existing in the prior art, the present application provides a method for preparing a PBAT polyester from full-bio-based source monomers. The three monomers, adipic acid (AA), terephthalic acid (PTA) and 1,4-butanediol (BDO), are synthesized from biomass raw materials. The above three bio-based monomers are synthesized by using a bulk polymerization method, and a two-stage process route of esterification and polycondensation reaction is used to finally synthesize a full-bio-based PBAT polyester. The synthesis process is simple and easy to implement.

[0005] To achieve the above purpose, the technical scheme adopted by the present application is as follows: This invention provides a method for preparing a fully bio-based PBAT polyester, comprising the following steps: using three bio-based monomers—adipic acid, terephthalic acid, and 1,4-butanediol—as raw materials, and obtaining a fully bio-based PBAT polyester material through an esterification-polymerization reaction, wherein all three bio-based monomers are synthesized from biomass raw materials.

[0006] Furthermore, the preparation method of the above-mentioned fully bio-based PBAT polyester includes the following steps: Step 1: Under the protection of an inert atmosphere, adipic acid, terephthalic acid, 1,4-butanediol and catalyst are added to the reactor and reacted at 180~220 ℃ and atmospheric pressure for 2~8 hours. Step 2: After the reaction is complete, heat to 230~250 ℃ for polycondensation reaction for 3~8 hours, and at the same time use a vacuum pump to remove small molecule by-products generated in the reaction. After the polycondensation reaction is completed, crude PBAT product is obtained. Step 3: Add an organic solvent to the crude PBAT product to completely dissolve it, then add an alcohol to produce a precipitate. Filter and dry the precipitate to obtain the fully bio-based PBAT polyester.

[0007] Furthermore, the catalyst is one or more of solid acid catalysts, including titanates, stannous octoate, germanium dioxide, and antimony trioxide.

[0008] Furthermore, the amount of catalyst used can be a small amount commonly used by those skilled in the art. Preferably, the ratio of the mass of the catalyst to the total mass of the three bio-based monomers is 0.01:100 to 2:100, and more preferably 0.03:100 to 1:100.

[0009] Furthermore, among the three bio-based monomers, the molar ratio of adipic acid to terephthalic acid is (7:3) to (3:7), and the molar ratio of the total amount of adipic acid and terephthalic acid to 1,4-butanediol is 1:1.05 to 1:1.5.

[0010] Furthermore, in step one, the inert atmosphere includes one or more of nitrogen, argon, and helium.

[0011] Furthermore, in step one, the reaction temperature is 190~210 ℃ and the reaction time is 3~4 hours.

[0012] Furthermore, in step two, the reaction temperature is 240~245 ℃ and the reaction time is 3~4 hours.

[0013] Furthermore, in step two, after evacuation, the vacuum level inside the reactor is less than 50 Pa.

[0014] Furthermore, in step three, the organic solvent is one or a mixture of dichloromethane, trichloromethane, dimethyl sulfoxide, and tetrahydrofuran.

[0015] Furthermore, in step three, the alcohol is one or a mixture of methanol, ethanol, and isopropanol, with methanol being more preferred. The amount of alcohol used is not limited; the purpose is to ensure complete precipitation of the formed fully bio-based PBAT polyester, facilitating separation and purification.

[0016] The beneficial effects of this invention are: I. The raw materials for preparing bio-based monomers in this invention are all derived from biomass resources, and the synthesized PBAT polyester does not rely on fossil raw materials at all, thus achieving green production from the source.

[0017] II. This invention achieves the synthesis of fully bio-based PBAT polyester using a simple preparation method, with high production efficiency and performance comparable to petroleum-based PBAT, showing promising application prospects. Attached Figure Description Figure 1 The results of FT-IR testing of the all-bio-based PBAT polyester prepared in Example 1 are as follows; Figure 2 The fully bio-based PBAT polyester prepared in Example 1 1 H NMR results; Figure 3 The stress-strain test results are for the fully bio-based PBAT polyester prepared in Example 1. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1 This invention provides a method for preparing a fully bio-based PBAT polyester, comprising the following steps: (1) Bio-based monomers adipic acid (AA), terephthalic acid (PTA), and 1,4-butanediol (BDO) were weighed out in a molar ratio of 1:1:2.2 and added to a reactor for melting and mixing. At the same time, 0.3% of tetrabutyl titanate catalyst was added to the total reaction system. The reaction temperature of the reactor during the esterification reaction was set at 210 °C and the stirring speed was set at 500 r / min. The reaction time was 4 hours, after which the temperature was raised to 240 °C and a vacuum pump was connected to evacuate the system to a pressure of 50 Pa for 4 hours of polycondensation reaction. After the reaction was completed, the product was discharged and cooled to room temperature.

[0020] (2) The polyester sample obtained from the reaction was completely dissolved in chloroform, and then excess methanol was added, resulting in the precipitation of a white precipitate. After filtration, the white precipitate was dried at 60 °C for 12 h to obtain a white solid, which was washed with methanol and dried for later use. The structure of the product was analyzed by FT-IR and 1H NMR, and the results are as follows: Figure 1 , Figure 2 As shown. Stress-strain tests were performed on the product, and the results are as follows. Figure 3 As shown, its fracture strength reaches 18 MPa and its elongation at break is 830%.

[0021] Example 2 This invention provides a method for preparing a fully bio-based PBAT polyester, comprising the following steps: (1) Bio-based monomers AA, PTA, and BDO were weighed in a molar ratio of 1:1:2.4 and added to a reactor for melting and mixing. At the same time, 0.3% of tetrabutyl titanate catalyst by mass of the total reaction system was added. The reaction temperature of the reactor during the esterification reaction stage was set at 210 °C, and the stirring speed was set at 500 r / min. The reaction time was 4 hours, after which the temperature was raised to 240 °C, and a vacuum pump was connected to evacuate the system to a pressure of 50 Pa for 4 hours of polycondensation reaction. After the reaction was completed, the product was discharged and cooled to room temperature.

[0022] (2) The separation and purification of the product were carried out in the same manner as in Example 1. The stress-strain test results were as follows: fracture strength 16.5 MPa, elongation at break 850%.

[0023] Example 3 This invention provides a method for preparing a fully bio-based PBAT polyester, comprising the following steps: (1) Bio-based monomers AA, PTA, and BDO were weighed out in a molar ratio of 1:1:2.2 and added to a reactor for melting and mixing. At the same time, 0.3% of tetrabutyl titanate catalyst was added to the total reaction system. The reaction temperature of the reactor during the esterification reaction was set to 200 ℃, and the stirring speed was set to 500 r / min. The reaction time was 4 hours, after which the temperature was raised to 245 ℃, and a vacuum pump was connected to evacuate the system to a pressure of 50 Pa for 4 hours of polycondensation reaction. After the reaction was completed, the product was discharged and cooled to room temperature.

[0024] (2) The separation and purification of the product were carried out in the same manner as in Example 1. The stress-strain test results were as follows: the fracture strength was 16.9 MPa and the elongation at break was 650%.

[0025] Example 4 This invention provides a method for preparing a fully bio-based PBAT polyester, comprising the following steps: (1) Bio-based monomers AA, PTA, and BDO were weighed out in a molar ratio of 1:1:2.2 and added to a reactor for melting and mixing. At the same time, 0.3% of stannous octoate catalyst by mass of the total reaction system was added. The reaction temperature of the reactor during the esterification reaction was set at 210 °C and the stirring speed was set at 500 r / min. The reaction time was 4 hours. After that, the temperature was raised to 240 °C and a vacuum pump was connected to evacuate the system to a pressure of 50 Pa for 4 hours of polycondensation reaction. After the reaction was completed, the product was discharged and cooled to room temperature.

[0026] (2) The separation and purification of the product were carried out in the same manner as in Example 1. The stress-strain test results were as follows: the fracture strength was 15.2 MPa and the elongation at break was 530%.

[0027] Example 5 This invention provides a method for preparing a fully bio-based PBAT polyester, comprising the following steps: (1) Bio-based monomers AA, PTA, and BDO were weighed out in a molar ratio of 1:1:2.2 and added to a reactor for melting and mixing. At the same time, 0.3% of tetrabutyl titanate catalyst was added to the total reaction system. The reaction temperature of the reactor during the esterification reaction was set at 210 °C and the stirring speed was set at 500 r / min. The reaction time was 3 hours. After that, the temperature was raised to 240 °C and a vacuum pump was connected to evacuate the system to a pressure of 50 Pa for 3 hours of polycondensation reaction. After the reaction was completed, the product was discharged and cooled to room temperature.

[0028] (2) The separation and purification of the product were carried out in the same manner as in Example 1. The stress-strain test results showed that the fracture strength was 16.1 MPa and the elongation at break was 505%.

[0029] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a fully bio-based PBAT polyester, characterized in that, Includes the following steps: Using three bio-based monomers—adipic acid, terephthalic acid, and 1,4-butanediol—as raw materials, a fully bio-based PBAT polyester material was obtained through esterification-polymerization reaction; all three bio-based monomers were synthesized from biomass raw materials.

2. The method for preparing the fully bio-based PBAT polyester according to claim 1, characterized in that, Includes the following steps: Step 1: Under the protection of an inert atmosphere, adipic acid, terephthalic acid, 1,4-butanediol and catalyst are added to the reactor and reacted at 180~220 ℃ and atmospheric pressure for 2~8 hours. Step 2: After the reaction is complete, heat to 230~250 ℃ for polycondensation reaction for 3~8 hours, while using a vacuum pump to evacuate the vacuum. After the polycondensation reaction is complete, crude PBAT product is obtained. Step 3: Add an organic solvent to the crude PBAT product to completely dissolve it, then add an alcohol to produce a precipitate. Filter and dry the precipitate to obtain the fully bio-based PBAT polyester.

3. The method for preparing the fully bio-based PBAT polyester according to claim 2, characterized in that, The catalyst includes one or more of titanates, stannous octoate, germanium dioxide, and antimony trioxide.

4. The method for preparing the fully bio-based PBAT polyester according to claim 2, characterized in that, The mass ratio of the catalyst to the total mass of the three bio-based monomers is from 0.01:100 to 2:

100.

5. The method for preparing the fully bio-based PBAT polyester according to claim 2, characterized in that, Among the three bio-based monomers, the molar ratio of adipic acid to terephthalic acid is (7:3) to (3:7), and the molar ratio of the total amount of adipic acid and terephthalic acid to 1,4-butanediol is 1:1.05 to 1:1.

5.

6. The method for preparing the fully bio-based PBAT polyester according to claim 2, characterized in that, In step one, the inert atmosphere includes one or more of nitrogen, argon, and helium.

7. The method for preparing the fully bio-based PBAT polyester according to claim 2, characterized in that, In step one, the reaction temperature is 190~210 ℃ and the reaction time is 3~4 hours; In step two, the reaction temperature is 240~245 ℃ and the reaction time is 3~4 hours.

8. The method for preparing the fully bio-based PBAT polyester according to claim 2, characterized in that, In step two, after evacuation, the vacuum level inside the reactor is less than 50 Pa.

9. The method for preparing the fully bio-based PBAT polyester according to claim 2, characterized in that, In step three, the organic solvent is one or more of dichloromethane, trichloromethane, dimethyl sulfoxide, and tetrahydrofuran.

10. The method for preparing the fully bio-based PBAT polyester according to claim 2, characterized in that, In step three, the alcohol is one or more of methanol, ethanol, and isopropanol.

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