A heat-resistant and impact-resistant polylactic acid composite material and its preparation method and application

Abstract

The invention discloses a heat-resistant and impact-resistant polylactic acid composite material as well as a preparation method and application thereof. The heat-resistant and impact-resistant polylactic acid composite material includes the following components calculated in parts by weight: 60-90 parts of polylactic acid, 5-25 parts of polybutylene terephthalic acid / adipate, 1-25 parts of compatibilizer 5 parts, 1-9 parts of active nano-calcium carbonate and 0.1-1 part of antioxidant; the active nano-calcium carbonate is prepared by modifying nano-calcium carbonate. The preparation method provided by the present invention adopts the technology of first banburying and then blending, so that the prepared heat-resistant and shock-resistant polylactic acid composite material is more uniformly dispersed, and has excellent mechanical properties, impact resistance, heat resistance and complete biological properties. Degradability, it has a good application prospect in the field of heat-resistant packaging such as hot meal containers.

Description

technical field [0001] The invention belongs to the technical field of polymer material modification, and specifically relates to a heat-resistant and shock-resistant polylactic acid composite material and its preparation method and application, in particular to a heat-resistant and shock-resistant PLA / PBAT / nanometer calcium carbonate composite material and its preparation Methods and applications. Background technique [0002] Polylactic acid (PLA) is a completely biodegradable material that uses corn and other plant resources as raw materials, obtains lactic acid through fermentation, and cyclizes lactic acid to form lactide, which is then synthesized under a ring-opening catalyst. Polylactic acid (PLA) has good biocompatibility, water resistance, thermal stability, transparency, hand feeling and comprehensive mechanical properties; it is widely used in packaging, catering, textiles, medical polymers, 3D printing and other fields. However, PLA also has some significant di...

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Problems solved by technology

However, PLA also has some significant disadvantages: low heat distortion temperature, the product can only be used in normal temperature or medium temperature environment, and its use in the field of electronic devices and hot meal containers is limited; it is brittle, poor in flexibility, and not resistant to impact. Application of the value field is restricted

At present, there are the following difficulties and shortcomings in the method of improving the heat resistance and impact resistance of polylactic acid (PLA) by blending PBAT, nanomaterials and PLA: (1) Due to the difference in molecular structure, the polarity of PLA and PBAT is large, and the two have a common Mixed almost incompatible, poor mechanical properties

However, the compatibilizers currently available in the market are not targeted, and the improvement of the fracture strain rate and impact strength of the blend is limited, and the compatibility efficiency is low.

Compatibilizers for PLA / PBAT blends mostly use reactive polymerization methods, which are difficult to prepare and require many processes

(2) The current research on PLA / PBAT composite materials focuses on single functions such as toughening, heat resistance, controllable degradation, and high tensile strength, and the research on dual functions is lacking

(3) Nanomaterials such as nano-calcium carbonate have small particle size, large surface energy, strong interaction between particles, easy agglomeration, and are difficult to evenly disperse in the resin matrix

Patent CN109721977A discloses a high-impact PLA / PBAT composite material and its preparation method. In this patent, PBAT is first chemically grafted, and the grafted PBAT content is more than 20%, and then blended with PLA to obtain an alloy. Composite material requires more than 20% grafting rate of grafted PBAT, which is not easy to obtain; patent CN110079065A discloses a high-toughness PLA / PBAT blend alloy and its preparation method. This patent first synthesizes and prepares compatibilizer PDLA-PBAT -PDLA three-block polymer, and then PLA, PBAT, PDLA-PBAT-PDLA three-block polymer are added to the internal mixer to melt to obtain an alloy, and the synthesis process of the compatibilizer PDLA-PBAT-PDLA three-block polymer is relatively Many, and need to use chloroform, chloroform is highly toxic and not environmentally friendly

Overcome the disadvantages of low thermal deformation temperature and high brittleness of PLA materials, and play a major role in expanding the application of PLA in high value-added fields

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