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Method for preparing high-melting-point stereo-complex polylactic acid material

A compound polylactic acid and high melting point technology is applied in the field of preparation of high melting point stereocomposite polylactic acid materials, and can solve the problems of limited application scope, poor mechanical properties, and inconsistency.

Inactive Publication Date: 2015-10-28
CHANGZHOU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] Polylactic acid is a renewable and environmentally friendly plastic with good biocompatibility and can be degraded in nature. It is a polymer material that can be plastically processed and has high strength; commercialized polylactic acid PLLA The glass transition temperature T g It is about 60°C, and the melting point is about 155~175°C. Therefore, the defects in heat resistance and mechanical properties will limit the application range of polylactic acid materials; based on the poor thermal and mechanical properties of polylactic acid, many researchers Many methods have been tried to improve these properties, such as copolymerizing it with other monomers, and the two molecular chains can form a stereocomplex through the special hydrogen bond force between the molecular chains --- SC -PLA has completely different properties from ordinary PLLA and its derivatives; stereocomposite materials are a kind of polymer material with unique properties formed by mixing two components with the same composition and different stereo configurations, polylactic acid The melting point of the stereocomplex SC crystal is as high as 230°C, and it has excellent heat resistance stability, high mechanical properties and stable degradation characteristics; optical purity, ratio, preparation method, molecular weight, etc. will affect the formation of SC crystal, and optical purity is an influence As an important factor in the structure and physical properties of polylactic acid and stereocomplexes, there are not many and systematic studies on the influence of optical purity on SC crystals by scholars at home and abroad. In addition, there are relatively few studies on the practical application of SC crystals.

Method used

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  • Method for preparing high-melting-point stereo-complex polylactic acid material
  • Method for preparing high-melting-point stereo-complex polylactic acid material
  • Method for preparing high-melting-point stereo-complex polylactic acid material

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Experimental program
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Effect test

Embodiment 1

[0028] Recipe: about 20g of L-lactic acid, 10g of D-lactic acid, 0.04g of trimethylolethane, 0.06mL of stannous octoate, and 50mL of anhydrous toluene.

[0029] First, add the reactants such as purified L-lactide, trimethylolethane and stannous octoate into the three-necked flask according to the above ratio, and fill it with N 2 , then vacuumize, repeat 3 times, keep the pressure in the polymerization tube at 1 ~ 10kPa, then seal the tube in vacuum, react at 180°C for 2h, then lower the temperature to 130°C, and continue the reaction for 48h to obtain a light yellow product. After the product is purified and dried, the three-arm branched PLLA prepolymer of white powder is obtained; the prepolymer and excess Sn(Oct) 2 dissolved in anhydrous toluene in N 2Under protection, the reaction was continued at 60°C for 4 h; after the reaction, suction filtration was performed and washed with anhydrous toluene to remove unreacted stannous octoate and low molecular weight soluble produc...

Embodiment 2

[0031] Recipe: about 20g of L-lactic acid, 20g of D-lactic acid, 0.04g of trimethylolethane, 0.06mL of stannous octoate, and 50mL of anhydrous toluene.

[0032] First, add the reactants such as purified L-lactide, trimethylolethane and stannous octoate into the three-necked flask according to the above ratio, and fill it with N 2 , then evacuate, repeat 3 times, keep the pressure in the polymerization tube at 1-10kPa, and then vacuum seal the tube; react at 180°C for 2h, then lower the temperature to 130°C, and continue the reaction for 48h to obtain a light yellow product. After the product is purified and dried, the three-arm branched PLLA prepolymer of white powder is obtained; the prepolymer and excess Sn(Oct) 2 dissolved in anhydrous toluene in N 2 Under protection, the reaction was continued at about 60°C for 4 hours. After the reaction, suction filtration and washing with anhydrous toluene removed unreacted stannous octoate and low molecular weight soluble products; af...

Embodiment 3

[0034] Recipe: about 20g of L-lactic acid, 60g of D-lactic acid, 0.04g of trimethylolethane, 0.06mL of stannous octoate, and 50mL of anhydrous toluene.

[0035] First, add the reactants such as purified L-lactide, trimethylolethane and stannous octoate into the reaction kettle according to the above ratio, and fill it with N 2 , then vacuumize, repeat 3 times, keep the pressure in the polymerization tube at 1 ~ 10kPa, then seal the tube in vacuum, react at 180°C for 2h, then lower the temperature to 130°C, and continue the reaction for 48h to obtain a light yellow product. After the product is purified and dried, the three-arm branched PLLA prepolymer of white powder is obtained; the prepolymer and excess Sn(Oct) 2 dissolved in anhydrous toluene in N 2 Under protection, the reaction was continued at about 60°C for 4 hours. After the reaction was completed, it was filtered with suction and washed with anhydrous toluene to remove unreacted stannous octoate and low molecular wei...

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Abstract

The invention discloses a method for preparing a high-melting-point stereo-complex polylactic acid material. According to the method, the purified L-lactide and an initiator are subjected to ring-opening polymerisation to generate a three arm-branched levorotatory polylactic acid prepolymer. After that, the prepolymer is subjected to end-group activation treatment to realize the hydroxyl-terminated activation of the prepolymer. The activated prepolymer and D-lactide are subjected to ring-opening polymerization. Through changing the application amount of D-lactide, three arm-branched L-polylactide-R polylactide segmented copolymers of different molecular weights can be synthesized. The weight-average molecular weight of the three arm-branched L-polylactide-R polylactide segmented copolymers is 5000-45000. DSC results show that, PLLA-PDLA segmented copolymers can generate stereo-complex crystals in certain conditions. The melting temperature of the above crystalline region is over 220 DEG C. Based on the above method, the high-melting-point stereo-complex polylactic acid material can be successfully prepared.

Description

technical field [0001] The invention relates to a preparation method of a high-melting point stereocomposite polylactic acid material, which belongs to the field of biodegradable polymer materials. Background technique [0002] Polylactic acid is a renewable and environmentally friendly plastic with good biocompatibility and can be degraded in nature. It is a polymer material that can be plastically processed and has high strength; commercialized polylactic acid PLLA The glass transition temperature T g It is about 60°C, and the melting point is about 155~175°C. Therefore, the defects in heat resistance and mechanical properties will limit the application range of polylactic acid materials; based on the poor thermal and mechanical properties of polylactic acid, many researchers Many methods have been tried to improve these properties, such as copolymerizing it with other monomers, and the two molecular chains can form a stereocomplex through the special hydrogen bond force ...

Claims

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Application Information

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IPC IPC(8): C08G63/664C08G63/08C08G63/78C08G63/85
Inventor 李锦春李雄杰刘雨邹国享赵彩霞
Owner CHANGZHOU UNIV