In situ preparation of polyaniline coated fumed and precipitated silica fillers and their composites with nitrile rubber (Investigation on structure-property relationship)

In situ synthesis of polyaniline (PAni) coated pyrogenic or fumed silica (PCFS) and precipitated silica (PCPS) were carried out by the oxidative polymerization of aniline in presence of fumed silica (FS) and precipitated silica (PS). Both uncoated and PAni coated silica fillers were characterized through scanning electron microscope (SEM), infrared spectroscopy and thermo-gravimetric analysis (TGA) to evaluate particle morphology and physico-chemical character of coated and uncoated silica particles. Semi-conducting composites made from two different types of PAni coated silica fillers with NBR exhibit different trend in the variation of electrical properties under different temperature and pressure. These differences in electrical properties of two types of composites are mainly due to physico-chemical characteristics of filler particles as well as their distribution in the polymer matrix. This type of composites may be used as semi-conducting and ESD (electrostatic discharge) material.