Morphology and properties tuning of PLA/cellulose nanocrystals bio-nanocomposites by means of reactive functionalization and blending with PVAc

A novel method for the preparation of PLA bio-nanocomposites containing cellulose nanocrystals (CNCs) is reported. In order to enhance interfacial adhesion and dispersion of nanocrystals into PLA matrix, functionalization of PLA and CNCs by radical grafting of glycidyl methacrylate (GMA) and pre-dispersion of CNCs in poly (vinyl acetate) (PVAc) emulsion were applied. Morphologies, thermal and mechanical properties of nanocomposites for CNCs content of 1–6 wt.% were examined. Addition of functionalized components (PLA-GMA, CNC-GMA) and/or PVAc dispersed CNCs both improved the phase distribution of nanofiller and tensile properties, compared to the binary PLA/CNC nanocomposites. Thermal analyses demonstrated that glass transition, melting temperature and crystallinity of PLA were affected by the PVAc amount. Nanocomposites with PVAc dispersed CNCs exhibited higher thermal resistance than other composites. The filler effectiveness (CFE) was evaluated for all samples on the basis of storage modulus values: CNC-GMA and PVAc dispersed CNCs (3 wt. %) resulted the most effective fillers.