Synthesizing polystyrene/carbon nanotube composites by emulsion polymerization with non-covalent and covalent functionalization

Polymer/carbon nanotube (CNT) composites were synthesized by first attaching functional groups onto CNT to make them reactive. For this purpose, we developed a combined approach of non-covalent and covalent functionalization process. Covalent functionalization was accomplished through refluxing of CNT with mineral acid (HNO3) and with oleic acid. The FTIR spectra and zeta-potential data confirmed the effectiveness of functionalization and the improved dispersibility of the functionalized CNT. Styrene was used to synthesize polystyrene (PS)/CNT composites in conjunction with emulsion polymerization, a versatile and industrially important method that is seldom reported for composite synthesis. Our PS/CNT composites had high monomer conversion and the measured thermal and mechanical properties showed significant improvements over pure PS even with modest CNT content. (C) 2010 Elsevier Ltd. All rights reserved.