A kind of preparation method of polylactic acid compound

Abstract

The invention discloses a preparation method of a polylactic acid compound, comprising: under an inert atmosphere, carrying out a lactide monomer, an unsaturated monomer and a catalyst composition in a solvent at a temperature higher than 180 to 250°C and under airtight conditions reaction to obtain a polylactic acid compound. According to the method provided by the invention, the reaction can be carried out at a relatively high temperature (greater than 180° C.) to obtain a cross-linked polylactic acid compound without discoloration, which overcomes technical prejudice and obtains a high-molecular weight cross-linked polylactic acid compound. According to the method provided by the present invention, the unsaturated monomer is used to modify lactic acid, and the carbon-carbon double bond is opened to undergo a cross-linking reaction to obtain a polylactic acid compound with a cross-network structure, which can effectively improve the mechanical properties of the modified polymer, improve thermal stability of polylactic acid composites.

Description

technical field [0001] The invention belongs to the field of polymer synthesis, and in particular relates to a synthesis method of a polylactic acid modified compound. Background technique [0002] With the development of science and society, environmental and resource issues have become one of the hot spots in the world. Petroleum-based plastic materials are widely used, but they are difficult to recycle after use, resulting in serious white pollution. Petroleum resources are non-renewable, and a large amount of unreasonable use has brought serious resource shortage problems to human beings. Polylactic acid is an ideal environment-friendly material prepared from lactic acid obtained by fermentation (or chemical synthesis) of starch (environmentally renewable resources). It not only has good physical and processing properties, but also has good biological phase Capacitance and degradability, especially renewability and degradability are effective means to solve the current...

AI Technical Summary

Problems solved by technology

Polylactic acid with a single molecular structure and functional group is obviously difficult to achieve this goal

In addition, polylactic acid is a polyester material, and the factors in the culture medium adsorbed on its hydrophobic surface are not easily replaced by the factors secreted by the cells themselves during the growth process. Compared with the hydrophilic surface, it is not conducive to the realization of cell physiological functions. , which has also become a major limitation in the application of tissue engineering, so it is also necessary to change the hydrophilic / hydrophobic state of the material surface

[0004] In the prior art, there have been documents disclosing modified polylactic acid containing double bonds obtained after modification with maleic anhydride or maleic amide, but the mechanical properties of the obtained polymer are not high and the thermal stability is poor; at the same time, the document It is also disclosed that the reaction temperature higher than 180°C will cause discoloration of the obtained modified polymer, so it needs to be reacted for a long time at a temperature lower than 180°C to obtain a modified polymer with a relatively low molecular weight

[0005] The common polymerization method of polylactic acid is bulk polymerization. The production process of bulk polymerization is simple, the process is short, easy to be continuous, and the production cost is low. , mixing and heat transfer are difficult; the molecular weight distribution of the product is wide, the unreacted monomer is difficult to remove, and the mechanical properties of the product are deteriorated, etc.

If solution polymerization is used, because the polymerization temperature is high, there are problems such as solvent selection and low polymerization rate.

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