Preparation and molecular simulation of hyper-dispersant modified BN filled natural rubber thermally conductive composite

Abstract

Non-covalent modification of fillers with hyperdispersants in composite processing avoids destroying the regular structure of the filler and is simpler and easier to operate than ordinary surface modification methods. A novel hyperdispersant, GI-g-PHA, was synthesized by esterification of poly12-hydroxystearic acid (PHA) and glycerol (GI) to improve the thermal conductivity (TC) and tensile properties of natural rubber (NR)/boron nitride (BN) composites. After the addition of 5 wt% hyperdispersant, the thermal conductivity of 20 vol% and 25 vol% BN composites was 0.965 W/mK and 1.364 W/mK, respectively, which was 9.6 and 13.6 times higher than that of NR matrix (0.1 W/mK). Molecular dynamics simulations showed an increase in molecular binding energy and a decrease in free volume fraction after the addition of dispersant, which provided a microscopic explanation for the change in compatibility. This study provides a way to prepare polymer matrix composites with high thermal conductivity and high strength.