Effects of carboxymethyl chitosan-assisted dispersion of silica on interface and mechanical properties of rubber composites

Abstract

Uniform distribution of fillers and strong adhesion at the rubber-filler interface are two pivotal factors to fully utilize the special properties of nanofillers to strengthen rubber. Unfortunately, there are generous hydrogen-bond interactions between SiO2 nanoparticles because of the abundant active hydroxyl groups on their surfaces, contributing to the existence of a large number of SiO2 agglomerates in rubber matrix and the difficulty in forming strong interfacial interactions between SiO2 and rubber. In this study, carboxymethyl chitosan (CMCS) was used to assist the dispersion of SiO2 in carboxylic styrene butadiene rubber (XSBR) to prepare high-performance rubber composites via latex film-formation. Latex blending film-formation is a unique processing method that could maintain the original self-assembly structure of filler particles during film-formation to the greatest extent. The results revealed that the hydrogen bond formed between CMCS and SiO2 strikingly promoted a better dispersion and distribution of SiO2 in the XSBR matrix and enhanced the rubber-filler interfacial interactions. The tensile strength of XSBR/20 wt% SiO2 composite with CMCS was about 122 % higher than that of the composites without CMCS. Furthermore, based on the non-covalent interactions between the active groups of XSBR/CMCS/SiO2 composites and inorganic substrates, the composites could form strong adhesion to inorganic substrates.