A Water Dispersible Nanocomposite of Polyacrylonitrile with Silica via Aqueous Polymerization of Acrylonitrile by K2CrO4–NaAsO2 Redox System

Abstract

The aqueous polymerization of acrylonitrile initiated by the redox pair, potassium chromate-sodium arsenite produced polyacrylonitrile which was recovered as a coagulum in the medium. A simple procedure was developed for obtaining a stable suspension of polyacrylonitrile-SiO2 nanocomposite by conducting the polymerization in presence of SiO2 as a particulate dispersant. SEM analyses revealed distinct morphological features of the polyacrylonitrile-SiO2 nanocomposite. TEM analyses indicated the particle sizes of the polyacrylonitrile-SiO2 composite to be in the 28–100 nm range. TG analyses revealed the enhanced thermal stability of the polyacrylonitrile-SiO2 nanocomposite relative to that of the base polymer polyacrylonitrile. The d.c. conductivities of the polyacrylonitrile-SiO2 and polyacrylonitrile-SiO2 (FeCl3 doped) composites were in the order of 10-6 S cm-1 and 10-5 S cm-1 respectively.