Method for preparing transparent heat-resistance polylactic acid modification material

Abstract

The invention discloses a method for preparing a transparent heat-resistance polylactic acid modification material, in which three methods for improving the heat resistance of polylactic acid, namely a method for changing a polylactic acid crystal state by using a nucleating agent, a method for changing a polylactic acid molecular structure by the crosslinking of a chain extender and a method formixing the polylactic acid and high glass transition temperature (Tg) polymer materials, are adopted. The method comprises the following steps of: drying all raw material mixed complexes at 80 DEG C for 5 hours; and granulating or directly processing to form a transparent heat-resistance polylactic acid product. The polylactic acid modification material comprises the following raw materials in parts by weight: 100 parts of polylactic acid, 5-10 parts of chitin whisker polymethyl methacrylate coating, 0.5-2.0 parts of chain extender, 3-5 parts of oligomer polylactic acid, and 0.1-0.5 part of 3-(nonyl-phenyl) phosphite ester. By using the method, the thermal deformation temperature of the polylactic acid composite material is over 100 DEG C, and the biodegradability and the high transparency of the composite material are effectively maintained.

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.