Hydrophobic cellulose nanocrystals modified with quaternary ammonium salts and its reinforcement of polystyrene

摘要

Cellulose nanocrystals(CNCs)were fabricated from cotton using sulfuric hydrolysis,followed with TEMPO/NaBr/NaClO oxidization and quaternary ammonium salts adsorption,namely stearyltrimethylammunium chloride(STAC),diallyldimethylammunium chloride(DTAC)and benzyltrimethylammuniun chloride(BTAC).Polystyrene-CNC composite films were prepared with solution casting method.The compatibility between CNCs and polymeric matrix were characterized with contact angle's measurement.The mechanical properties of composites were analyzed.The results revealed that the thermostability of CNCs and the compatibility of CNCs with polystyrene have been improved.The contact angle of the modified CNCs was increased than pure CNCs.In addition,the breaking strength and elongation at break of PS-CNC composites were increased,which indicated that the modified CNCs were dispersed evenly in the composites.The study shows that the combination of TEMPO-mediated oxidization and quaternary ammonium's adsorption is an effective method for improving the thermostability and compatibility of CNC in organic matrix.