(542e) Chemical Surface Modification of Cellulose Nanofibrils and Their Reinforcement Effect in Polystyrene Matrix

Cellulose nanofibrils (CNFs) have been of a great interest as reinforcing fillers due to their low weight, high aspect ratio, and excellent mechanical strength properties. The advantages of CNFs, however, are often limited by their aggregation tendency and interfacial compatibility with hydrophobic polymer matrices. Chemical surface modification of CNFs by polymer grafting is introduced to limit the intermolecular hydrogen bonding between nanofibrils by functionalizing surface hydroxyl groups of cellulose and to improve wettability with hydrophobic material while maintain its biodegradability and reinforcing capability. In this study, maleated styrene block copolymers were successfully grafted on the surface of CNFs through esterification. The evidences of grafting were identified through changes in chemical functional groups of CNFs. The influences of polymer grafting on the morphological, surface wetting, thermal stability, crystallinity, and solvent redispersion characteristics were evaluated and compared with those of neat CNFs. The reinforcing capability of modified CNFs as reinforcing fillers in polystyrene matrix was assessed. The study also explored the mechanical performance of different nanocomposite processing methods utilizing neat CNFs. The results of this study would provide indication on the effects of CNFs surface modification as reinforcing fillers in hydrophobic polymers.