Method for preparing transparent heat-resistance polylactic acid modification material

Abstract

The invention discloses a preparation method of a transparent heat-resistant polylactic acid modified material. At the same time, a nucleating agent is used to change the crystallization state of polylactic acid, a chain extender is cross-linked to change the molecular structure of polylactic acid, and polylactic acid is combined with a high glass transition temperature ( Tg) Polymer material blending these three methods to improve the heat resistance of polylactic acid, all the raw material mixtures are dried at 80°C for 5 hours, and then granulated or directly processed into transparent heat-resistant polylactic acid products; The raw material formula of the lactic acid modified material is composed of: 100 parts by weight of polylactic acid, 5-10 parts by weight of chitin whisker polymethyl methacrylate coating, 0.5-2.0 parts by weight of chain extender, 3 parts by weight of oligomer polylactic acid ~5 parts by weight, and 0.1~0.5 parts by weight of tris-(nonylphenyl)phosphite. The invention not only makes the thermal deformation temperature of the polylactic acid composite material exceed 100 DEG C, but also effectively maintains the biodegradability and high transparency of the composite material.

Description

technical field [0001] The invention relates to a preparation method of a transparent heat-resistant polylactic acid modified material, belonging to the field of polymer materials and their processing. Background technique [0002] Due to its excellent transparency and biodegradability, polylactic acid is expected to be used to replace non-degradable general-purpose plastics in packaging fields such as containers and films, fiber fields such as clothing, carpets, and automotive decorations, and molding materials such as electronic and electrical housings. widely applied. [0003] However, the glass transition temperature (Tg) of typical polylactic acid is 50-80°C, and the heat distortion temperature of polylactic acid products obtained by conventional processing methods usually does not exceed 60°C, which cannot meet the heat resistance requirements of many products. Therefore, poor heat resistance restricts the use of polylactic acid. [0004] The main technology to impro...

AI Technical Summary

Problems solved by technology

[0018] Chinese patent CN200810174648.5 Polylactic acid with high melting heat resistance discloses a method of modifying polylactic acid with a carboxyl end-capping agent to improve the heat resistance of molten polylactic acid, which has no substantial effect on the heat resistance of polylactic acid products sexual help

This method uses styrene copolymer as a blend, which reduces the biodegradability of the composite material

[0026] Through the disclosure of the above Chinese patents, it is found that in most modification methods for improving the heat resistance of polylactic acid, some non-transparent substances or substances with poor compatibility are introduced into the system, resulting in a decrease in the transparency of the polylactic acid composite material

[0027] Polylactic acid is blended with polycarbonate and polyester polymer materials, although good transparency and heat resistance can be obtained, but the high proportion of non-bio-based materials reduces the biodegradability of polylactic acid composites

Therefore, on the basis of ensuring high biodegradability, it is still difficult to use existing technologies to make polylactic acid have high transparency and high heat resistance.