Crystallization mechanism and performance of polylactic acid regulated by the synergistic action of nanocrystalline cellulose and polyethylene glycol

Polylactic acid (PLA) is one of the most widely used biodegradable materials at present due to its excellent reproducibility and degradability. However, PLA still suffers from poor crystallinity, which seriously affects its development and application. Therefore, PLA/cellulose nanocrystalline (CNC)-polyethylene glycol (PEG) composite (PLA/CNC-PEG) was prepared by melt blending using CNC as nucleating agent and PEG as compatibilizer. The effect of PEG with different molecular weights (MW) on the properties of PLA/CNC-PEG composite was investigated. The experimental results shown that the crystallization properties of PLA were greatly improved under the synthetic action of CNC and PEG. With the increasing MW from 400 to 20,000 of PEG, the crystallinity of PLA/CNC-PEG composite decreased from 32.1% to 13.3%. In addition, the crystallization model of PLA/CNC-PEG was constructed to explore the mechanism of crystallization growth of PLA, effectively guiding the reduction of crystallization activation energy of PLA. Furthermore, it was found that PLA/CNC-PEG exhibited good thermal stability, mechanical properties, and hydrophilicity with the addition of CNC and PEG400. Therefore, the synthetic action of CNC and PEG well regulated the performance of PLA. The proposed work is of hopeful to expand the application of PLA in production and life.