Mechanical, thermal, and morphological properties of PLA biocomposites toughened with silylated bamboo cellulose nanowhiskers

To improve the surface compatibility between hydrophobic poly(lactic acid) (PLA) and hydrophilic bamboo cellulose nanowhiskers (BCNWs), four commercial available silane coupling agents were employed to modify their interfaces with different concentrations (0, 1, 8, and 16 wt%). PLA/BCNW biocomposite films were fabricated by solution casting. The effects of silylated BCNW on the thermal, mechanical, and morphological properties of PLA biocomposites were investigated. The coupled reaction between coupling agents and cellulose via Si-O-C bonding and hydrogen bonding was confirmed. Both, tensile strength and tensile modulus, decreased with the four silane treatments. The maximum elongation at break values increased to 213.8, 111.3, 255.3, and 209.8% after 16 wt% A-151, 8 wt% A-1100, 8 wt% A-174, and 8 wt% A-189 silane treatments, respectively, with respect to 12.4% of the untreated composite. A wire-drawing phenomenon was observed on the tensile fractural surface. Glass transition temperature and crystallinity decreased after the surface modifications. POLYM. COMPOS., 40:3012-3019, 2019. (c) 2018 Society of Plastics Engineers