Rheological, thermal, and mechanical characterizations of polystyrene/single-walled carbon nanotube composites

For preparation of polystyrene (PS) composites, a polymeric dispersant, pyrene-capped polystyrene (PyPS), was applied for noncovalent functionalization of single-walled carbon nanotubes (SWNTs) to improve both dispersion quality and PS-SWNT interfacial interactions. To demonstrate the critical role of PyPS, the composites with the absence of PyPS (PS/SWNT) were also prepared for comparison. Rheological studies suggest that addition of SWNTs, particularly of PyPS-functionalized SWNTs, suppresses significantly large-scale relaxation of PS chains but has little effect on their short-range dynamics. Relative to PS, moderately improved thermal and mechanical properties took place on the composites with either pristine or PyPS-functionalized SWNTs. The PS/PyPS/SWNT composite usually presents better performance than the PS/SWNT one at a fixed SWNT content.