MWCNTs与疏水纳米SiO_2填充PMMA/PS共混物的导电与动态流变行为

以多壁碳纳米管(MWCNTs)为导电填料、疏水纳米二氧化硅(SiO2)为非导电填料,填充不相容聚甲基丙烯酸甲酯(PMMA)/聚苯乙烯(PS)(1/1,V/V)共混物,制备(PMMA/SiO2)/(PS/MWCNTs)四元导电高分子复合材料(CPC),研究其导电逾渗与动态流变行为,并与PMMA/(PS/MWCNTs)三元CPC进行对比.发现三元、四元CPC具有类似的导电逾渗行为,且逾渗阈值显著低于PS/MWCNTs二元CPC.在四元CPC中,SiO2粒子可细化相区尺寸,提高熔体模量,但不影响熔体热处理过程中的依时性动态导电逾渗行为.MWCNTs与SiO2均显著影响熔体热处理中的依时性模量逾渗行为,分别缩短、延长四元CPC相粗化起始时间,但均延长相粗化时间区间.

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

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.