Percolation threshold of aligned SWNT polymer composites prepared by mechanical stretching
(0) The single-walled carbon nanotubes (SWNTs) filled nanocomposites SWNT/epoxy resin and SWNT/polyimide (PI) with good uniformity, dispersion and alignment of SWNTs and with different SWNTs concentrations were produced by solution casting and melt-mixing techniques, respectively. Subsequently, all the semidried mixture was stretched along one direction at a large draw-ratio of 50 and then folded it along the same direction and stretched repeatedly for 100 times at ambient atmosphere manually to achieve a good alignment and to prompt the dispersion of SWNTs in the composite matrix. The DC electrical volume conductivities of the composites rise with the increase of SWNT concentration, composites showed higher electrical conductivities along the stretched direction than perpendicular to it. With respect to pristine E-51, the electrical conductivity of 3 wt. ％ SWNT composite increases by 10 orders of magnitude, up to 10-6 S/cm. For SWNT/E51 composite with the same SWNTs loading of 1 wt. ％, the conductivity along the stretching direction was 3 orders of magnitude higher than perpendicular to it. The percolation threshold value for both SWNT/epoxy resin and SWNT/ PI composites along the stretching direction is lower than the value perpendicular to the SWNTs orientation. For SWNT/epoxy composite, the percolation threshold value along the stretching direction is 0.05 wt.％, which is lower than the value of 1 wt.％ perpendicular to the SWNTs orientation. The well aligned and dispersed SWNT modified SWNT/polymer composites follow percolation theory in a large SWNT loading rang from a small percolation threshold value to 10 wt. ％.
nanocomposite epoxy resin polyimide (PI) electrical conductivity percolation threshold
王青 戴剑锋 李维学 魏智强 姚东
兰州理工大学应用物理系,甘肃兰州730050;兰州理工大学甘肃省有色金属新材料省部共建国家重点实验室,甘肃兰州 730050 兰州理工大学应用物理系,甘肃兰州 730050
国际会议
成都
英文
2007-11-19（万方平台首次上网日期，不代表论文的发表时间）