ELECTRICAL CONDUCTION AND DYNAMIC RHEOLOGY OF MULTI-WALLED CARBON NANOTUBES AND HYDROPHOBIC NANOSILICA-FILLED IMMISCIBLE POLY(METHYLMETHACRYLATE)/POLYSTYRENE BLENDS

Abstract

Multi-walled carbon nanotubes(MWCNTs) and hydrophobic nanosilica(SiO2) were used as conductive and nonconductive fillers to fill immiscible poly(methylmethacrylate)/polystyrene(PMMA/PS)(1/1 in volume) blends to prepare(PMMA/SiO2)/(PS/MWCNTs) quaternary conductive polymer composites(CPCs).Conductive percolation at room temperature and melt dynamic rheology of the quaternary CPCs were investigated and were compared with PMMA/(PS/MWCNTs) ternary CPCs containing 5 vol% SiO2.The ternary and the quaternary CPC exhibited similar percolation behavior with percolation threshold of MWCNTs volume fractions much smaller than that of PS/MWCNTs binary CPC.SiO2 particles could reduce the phase size and improve the melt complex modulus without influence the time-dependent dynamic conductive percolation during melt annealing.MWCNTs and SiO2 have different effects on the time-dependent dynamic modulus percolation during annealing of quaternary CPCs.It is believed that MWCNTs and SiO2 accelerated and decelerated the onset time for phase coarsening,respectively,while both significantly extended the time interval of phase coarsening.Morphological observation revealed that degree of phase coarsening decreased with increasing volume fraction of MWCNTs in ternary CPC during melt annealing.The presence of SiO2 could greatly restrain the coarsening in quaternary CPC.