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Preparation method of high molecular weight polylactic acid stereocomplex with melt stability

A technology of stereocomplex and melt stability, which is applied in the field of preparation of high-molecular-weight polylactic acid stereocomplex, can solve the problems of poor memory effect, difficult formation of sc, difficulty in forming a large amount or complete sc, etc., and achieves The effect of improving crystallization ability

Active Publication Date: 2015-08-05
SICHUAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, for high-molecular-weight PLA, it is difficult to form a large amount or complete sc during the cooling crystallization process of PLLA / PDLA melt processing, and the memory effect of the already formed sc is poor, and it is difficult to re-form sc after melting

Method used

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  • Preparation method of high molecular weight polylactic acid stereocomplex with melt stability

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] The weight average molecular weight was 2.1×10 5 g·mol -1 PLLA and 1.0 x 10 5 g·mol -1 PDLA, and a molecular weight of 1000 g·mol -1 PEG was dissolved in dichloromethane at a concentration of 1 g dl -1 . After complete dissolution, mix under vigorous stirring and solution cast at room temperature. PLLA:PDLA=1:1wt in PLLA / PDLA / PEG blend, PEG content is 3wt%. The solution-cast samples were vacuum-dried and heated rapidly at a rate of 100 °C / min under nitrogen protection using a differential scanning calorimeter (DSC), and then cooled slowly at a rate of 10 °C / min to 270 °C for 2 min. The melt-cooled sample was obtained at 0 °C, and the temperature was raised again at a rate of 10 °C / min to detect the crystallization parameters of the melt-cooled sample. The crystal structures of the solution-cast samples and the melt-cooled samples were characterized by wide-angle X-ray diffraction (WAXD).

Embodiment 2

[0027] The weight average molecular weight was 2.1×10 5 g·mol -1 and 1.0×10 5 g·mol -1 PLLA, PDLA, and a molecular weight of 1000 g·mol -1 PEG was dissolved in dichloromethane at a concentration of 1 g dl -1 . After complete dissolution, mix under vigorous stirring and solution cast at room temperature. PLLA:PDLA=1:1wt in PLLA / PDLA / PEG blend, PEG content is 5wt%. The solution-cast samples were vacuum-dried and heated rapidly by DSC at a rate of 100 °C / min under nitrogen protection, and then cooled slowly to 0 °C at a rate of 10 °C / min after isothermally at 270 °C for 2 minutes to obtain a melt-cooled sample, and The temperature was raised again at a rate of 10 °C / min to detect the crystallization parameters of the melt-cooled sample. And by WAXD to characterize the crystal structure of the solution cast sample and the sample after melt cooling.

Embodiment 3

[0029] The weight average molecular weight was 2.1×10 5 g·mol -1 and 1.0×10 5 g·mol -1 PLLA, PDLA, and a molecular weight of 1000 g·mol -1 PEG was dissolved in dichloromethane at a concentration of 1 g dl -1 . After complete dissolution, mix under vigorous stirring and solution cast at room temperature. PLLA:PDLA=1:1wt in PLLA / PDLA / PEG blend, PEG content is 7wt%. The solution-cast samples were vacuum-dried and heated rapidly by DSC at a rate of 100 °C / min under nitrogen protection, and then cooled slowly to 0 °C at a rate of 10 °C / min after isothermally at 270 °C for 2 minutes to obtain a melt-cooled sample, and The temperature was raised again at a rate of 10 °C / min to detect the crystallization parameters of the melt-cooled sample. And by WAXD to characterize the crystal structure of the solution cast sample and the sample after melt cooling.

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Abstract

The invention discloses a preparation method for a high-molecular weight polylactic acid steric compound with fusion stability. The preparation method comprises the following steps of (1) preparing poly-levolactic acid, poly-dextrolactic acid and plasticizer polyethylene glycol according to a certain weight ratio; (2) respectively dissolving the poly-levolactic acid, the poly-dextrolactic acid and the polyethylene glycol in an organic solvent, performing mixing and solution-casting under the condition of intense agitation after the poly-levolactic acid, the poly-dextrolactic acid and the polyethylene glycol are completely dissolved, and performing vacuum drying on a solution-casting sample; and (3) rapidly heating the solution-casting sample to 230 to 270 DEG C at a speed of 100 DEG C / minute under the condition of nitrogen protection after the vacuum drying, and slowly cooling at a speed of 10 DEG C / minute after 2 minutes of constant temperature. According to the preparation method, a very high possibility is provided for reserving, properties, such as the excellent mechanical property, the heat resistance and the like, of the polylactic acid steric compound in fused products.

Description

technical field [0001] The invention belongs to the technical field of polymer materials, and in particular relates to a preparation method of a high-molecular-weight polylactic acid stereocomplex with melt stability. Background technique [0002] Since the beginning of the 21st century, the problems of plastic pollution and petrochemical resources have become the focus of worldwide attention. The sustainable development of biodegradable polymer materials using biomass and natural resources as raw materials has become a research and application development direction that has attracted worldwide attention. Polylactic acid (PLA) is currently the most widely used variety of synthetic biodegradable polymer materials, and it will gradually partially replace polyolefins and be widely used in the field of general plastics. However, some properties of polylactic acid itself need to be improved. For example, the heat resistance of polylactic acid is poor, and the heat distortion temp...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08L67/04C08L71/08
Inventor 杨伟包睿莹龚涛魏馨丰谢邦互杨鸣波
Owner SICHUAN UNIV
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