Bio-based green composites with high performance from poly(lactic acid) and surface-modified microcrystalline cellulose

Abstract

Bio-based green composites with high performance were prepared from poly(lactic acid) (PLA) and microcrystalline cellulose (MC) fibers grafted with L-lactic acid oligomers (g-MC). The chemical structure of g-MC was characterized by fourier transform infrared (FTIR) and NMR methods, which indicate that L-lactic acid oligomers were successfully grafted onto MC. The grafting percentage of L-lactic acid oligomers is ca. 3.4%, and the average degree of polymerization of grafted L-lactic acid oligomers is ca. 10%. The improved compatibility between g-MC and PLA, caused by the grafting, results in an excellent dispersion of g-MC in the composites, and consequently a considerably improved transparence of the g-MC/PLA composites compared with that of the MC/PLA composites. In addition, due to the improved compatibility between g-MC and PLA, the g-MC/PLA composites exhibit better mechanical properties than pure PLA, with a high tensile strength of 70 MPa and a higher elongation at breakage. The enhanced properties, coupled with the excellent biocompatibility and degradability, offer the bio-based composites potential applications in biomedical fields and the packaging industry.