Uniaxially stretched polylactic acid stereocomplex and preparation method thereof

A technology of stereocomposite and uniaxial stretching, which is applied in the field of polymer composite materials, can solve the problems of affecting the heat resistance temperature and mechanical properties of products, and the low crystallinity of stereocomposite, and achieve large-scale industrial production and production The effect of high efficiency and good market prospects

Active Publication Date: 2020-07-24
CHANGCHUN INST OF APPLIED CHEMISTRY - CHINESE ACAD OF SCI +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] At present, stereocomplex polylactic acid is usually prepared by melting and blending L-polylactic acid and D-polylactic acid and then cooling and crystallizing. The final product will inevitably contain a certain amount of polylactic acid homogeneous crystals, and the stereocomplex crystallinity is low, which will affect the heat-resistant temperature and mechanical properties of the product

Method used

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preparation example Construction

[0039] The present invention also provides a preparation method of uniaxially stretched polylactic acid stereocomplex, comprising the following steps:

[0040] a) melt blending 50 parts by weight of L-polylactic acid, 50 parts by weight of D-polylactic acid and 15-30 parts by weight of a compatible blend, and cooling to obtain a polylactic acid blend with an amorphous structure;

[0041] The compatible blend comprises polyvinyl acetate and / or polyracemic lactic acid;

[0042] b) uniaxially stretching the polylactic acid blend to obtain a uniaxially stretched polylactic acid stereocomplex.

[0043] In the preparation method provided by the invention, firstly, the raw materials are melt-blended in proportion. Wherein, the raw materials include L-polylactic acid, D-polylactic acid and compatible blends, preferably also include anti-hydrolysis agent and / or chain extender; the L-polylactic acid, D-polylactic acid, compatibility The specific information and dosage ratio of the ble...

Embodiment 1

[0053] 50 parts by weight of L-polylactic acid (weight-average molecular weight 150,000, optical purity 99%), 50 parts by weight of D-polylactic acid (weight-average molecular weight 150,000, optical purity 99%), polyvinyl acetate (weight-average molecular weight 150,000 ) 30 parts by weight, 0.1 parts by weight of carbodiimide, 1 part by weight of pyromellitic dianhydride, blended in a torque rheometer, the blending temperature is 240 ° C, the rotating speed is 40 revolutions / min, blending The time is 10 minutes. The blended samples were cooled at room temperature and air, and cut into small pieces, and then pressed into 1mm thick sheets on a flat vulcanizer at 250°C under a pressure of 10MPa, and then quickly placed in a cold press under 10MPa Cool to room temperature under pressure. The pressed sheet was stretched to 10 times at 65°C at a stretching rate of 20mm / min, and then the stretched sheet was cooled to room temperature to obtain a uniaxially stretched polylactic aci...

Embodiment 2

[0063] 50 parts by weight of L-polylactic acid (weight average molecular weight 500,000, optical purity 95%), 50 parts by weight of D-polylactic acid (weight average molecular weight 500,000, optical purity 98%), polyracemic lactic acid (weight average molecular weight 30,000 ) 15 parts by weight, 1 part by weight of carbodiimide, 0.1 part by weight of bisepoxy bisphenol A-diglycidyl ether, blended in a torque rheometer, the blending temperature is 240 ° C, and the rotating speed is 120 rpm / min, the blending time is 5min. Cool the mixed sample in air at room temperature, cut into small pieces, press it into a 1mm thick sheet on a flat vulcanizing machine at 220°C under a pressure of 10MPa, and then quickly place it in a cold press to maintain pressure at 10MPa Cool to room temperature. The pressed sheet was stretched to 4 times at 100°C at a stretching rate of 100mm / min, and then the stretched sheet was cooled to room temperature to obtain a uniaxially stretched polylactic a...

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Abstract

The invention belongs to the field of polymer composite materials, and particularly relates to a uniaxially stretched polylactic acid stereocomplex and a preparation method thereof. The polylactic acid stereocomplex provided by the invention is prepared by carrying out melt blending and cooling on raw materials and then uniaxially stretching, wherein the raw material comprises the following components in parts by weight: 50 parts of poly-L-lactic acid; 50 parts of dextral polylactic acid; and 15-30 parts of a compatible blend, wherein the compatible blend comprises polyvinyl acetate and/or poly-racemic lactic acid. According to the polylactic acid stereocomplex and the preparation method thereof, the stereocomplex crystallinity, the heat-resistant temperature and the mechanical strength ofthe polylactic acid stereocomplex are obviously improved by strictly controlling the dosage ratio of the levorotatory polylactic acid and the dextrorotatory polylactic acid in the raw materials, a certain amount of the compatible blend is added and a uniaxial stretching process is adopted, so that the polylactic acid stereocomplex provided by the invention is simple in preparation process and high in production efficiency, can realize large-scale industrial production, and has a good market prospect.

Description

technical field [0001] The invention belongs to the field of polymer composite materials, and in particular relates to a uniaxially stretched polylactic acid stereocomplex and a preparation method thereof. Background technique [0002] Polylactic acid is a polymer material that is chemically synthesized after fermenting lactic acid from plant resources. After being discarded, it can be completely decomposed into water, carbon dioxide and organic matter under the action of microorganisms, etc., without polluting the environment. It is a typical plant source. biodegradable plastic. Since polylactic acid has the advantages of complete plant origin, complete biodegradability, biocompatibility, bioabsorbability and easy processing, it is an ideal substitute for petroleum-based polymer materials, whether it is in the field of biomedical materials, Or in the field of general-purpose plastics, they all show broad application prospects, which can effectively solve the white pollutio...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08L67/04C08L31/04C08K5/29B29C55/06C08J5/18
CPCC08L67/04B29C55/06C08J5/18C08L2205/08C08L2205/025C08L2201/08C08L2205/03C08L2205/035C08J2367/04C08J2467/04C08J2431/04C08K5/29B29K2067/046B29K2031/04C08L31/04Y02W90/10
Inventor 谢招旺韩常玉于彦存边俊甲董丽松
Owner CHANGCHUN INST OF APPLIED CHEMISTRY - CHINESE ACAD OF SCI
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