气相纳米碳纤维填充硅橡胶的流变行为与性能研究

Rheological Behavior and Properties of VGCF Filled Silicone Rubber

采用常规双辊共混工艺制备了气相纳米碳纤维（VGCF）填充硅橡胶复合材料，考察了VGCF含量对其导电、力学、线性流变行为的影响．结果表明：这种工业化工艺可实现VGCF在硅橡胶中的良好分散．VGCF的添加显著改善硅橡胶的导电和力学性能，改性效果可与碳管相媲美．低VGCF添加量（φ＝2．5 vol％）即可使电阻率降低到105Ω· cm级别；添加3．5 vol％ VGCF可使体系的拉伸强度和断裂伸长率分别提高300％和103％．在低频区，高含量填充体系（φ≥3 vol％）呈现典型的第二平台现象与弹性为主的流变行为，这与体系内部完善的VGCF网络结构形成密切相关．在高频区，复合体系的粘度与纯基体类似，VGCF的加入不影响硅橡胶的加工性能．

VGCF filled silicone rubber composites were prepared by two roll mills mixing method ,and the effects of VGCF content on their electrical ,thermal properties together with linear rheological behavior were investigated .The results showed that VGCF were well dispersed in rubber matrix using this industrial process method . The addition of VGCF significantly improved electrical and mechanical properties which showed similar modified effect as the addition of CNT in silicone rubber .2 .5 vol% VGCF filled silicone rubber had an electrical resistivity of 105 Ω· cm .Moreover ,the addition of 3 .5 vol% VGCF increased the tensile strength and elongation at break of composites by 300% and 103% respectively .At low frequency regions ,the existence of filler network in the composite with high VGCF content （φ ≥ 3 vol% ） caused“second plate” phenomenon and elasticity controlled rheological behavior .The similar viscosity of composites as matrix at high frequency regions indicated that the addition of VGCF had very limited effect on the processability of silicone rubber .