A kind of copolymerization modification method of polylactic acid series polymer

Abstract

The invention relates to a copolymerization modification method of a polylactic acid polymer. With lactic acid oligomers and a polyhydroxy compound as raw materials, copolymerization is carried out, and the polylactic acid polymer is obtained. The copolymerization modification method has the advantages that by adding the polyhydroxy compound, a high-viscosity system can be increased, and even the probability of chemical combination of carboxy functional groups on the lactic acid oligomers and hydroxy on the polyhydroxy compound under the solid phase condition can be increased; meanwhile, the polyhydroxy compound serves as a reactant and can be copolymerized with the multiple lactic acid oligomers, and thus a copolymer with the polylactic acid polymer as the main body is generated; the added copolymer has a large quantity of hydroxy and has hydrophily, polylactic acid has hydrophobicity, and thus the hydrophily of a polylactic acid modified material can be improved through combination of the copolymer and the polylactic acid. Besides, by means of the copolymerization modification method, the molecular weight of the polylactic acid polymer can be rapidly increased, and the performance of the polylactic acid polymer can be effectively controlled.

Description

technical field [0001] The invention relates to a method for copolymerization and modification of polylactic acid polymers. Background technique [0002] With the rapid development of science and technology, people's living standards are gradually improving, dietary conditions and lifestyles have also undergone great changes, and the dependence on polymer materials is becoming stronger and stronger. Almost all plastic materials are non-degradable plastics, which are discarded in large quantities after use, not only forming very serious white pollution, causing serious damage to nature, but also greatly affecting human physical and mental health. Therefore, the development of biodegradable materials is imminent. [0003] Polylactic acid is condensed from lactic acid, which is an environmentally friendly biodegradable material. Under composting conditions, polylactic acid can be completely biodegraded into carbon dioxide and water, and finally absorbed by biomass for photosyn...

AI Technical Summary

Problems solved by technology

[0006] In addition, in the process of direct polycondensation to polylactic acid, as the molecular weight of polylactic acid increases and the viscosity of the system increases, the rate of polymerization reaction will become slower and slower.

Conditions such as high temperature and high vacuum will increase the cost and difficulty of production, and competitive degradation reactions will also cause a bottleneck in the growth of molecular weight in the polymerization process of polylactic acid