High permittivity ceramics-filled acrylonitrile butadiene rubber composites: influence of acrylonitrile content and ceramic type

Abstract

Influence of acrylonitrile content and ceramic type on cure characteristics, mechanical, morphological, and dielectric properties of acrylonitrile butadiene rubber (NBR) vulcanizates was examined. Two types of ceramic filler, namely barium titanate (BT) and calcium copper titanate (CCTO), were synthesized by solid-state reactions. The ceramic powders were then characterized by X-ray diffraction, particle size analyzer, and scanning electron microscopy (SEM). Ceramic/rubber composites were then mixed in an internal mixer at 60 °C and a rotor speed of 60 rpm. Two acrylonitrile contents of NBR, namely 33 wt% and 42 wt%, were tested. Incorporation of ceramic fillers in NBR matrix and increasing acrylonitrile content shortened scorch and cure times, but increased minimum, maximum, and delta torque. Furthermore, SEM results revealed that the BT-filled NBR composites showed better filler–matrix interactions than the CCTO-filled NBR composites. This matches the better mechanical and dielectric properties of the BT-filled NBR composites.