通过溶液混合法制得聚氧化乙烯/炭黑(PEO/CB)复合材料,考察基体摩尔质量对复合材料网络构建的影响.随着基体摩尔质量的增加,复合体系中CB的团聚体数量增加,需要在更高的粒子含量下才能形成网络结构.通过对PEO/CB复合材料动态流变行为的研究,发现当PEO摩尔质量为104g/mol时,CB体积分数为0.67%时就检测到难松弛的网络结构.当基体摩尔质量为105 g/mol(或106g/mol)时,需要在更高的CB体积分数4.1%(或>8.3%)下才检测到网络的形成,说明高摩尔质量体系中CB粒子网络对流变响应不敏感.通过引入一个放大因子B,采用Guth-Gold方程描述CB粒子对复合体系的增强作用.结果表明,在摩尔质量较高的体系中CB团聚拓扑结构对复合材料黏弹性的贡献会减弱.同时得到低摩尔质量复合体系中网络的分形维数是2.0±0.1.
A series of poly (ethylene oxide ) /carbon black (PEO/CB) composites were prepared by solution compounding, and the influence of the matrix's molecular weight on the fabrication of the filler network was studied. With the increase of the molecular weight, the agglomeration of CB particles became more obvious, thus a higher content of CB was needed to form the network structure. According to the rheology test, when the molar mass of PEO was 104 g/mol, tanδ peak could be observed in the composites with the CB volume fraction of 0. 67%, revealing the formation of a filler network. With the matrix molar mass of 10^5 g/mol (or 106 g/mol) , only when the CB volume fraction reached 4. 1% (or over 8.3% ) , the filler network could be detected, which demonstrated that the viscoelastic behavior of the composites became less sensitive to the filler network with increasing the molar mass of the matrix. By introducing an amplification factor of B, the Guth-Gold equation could be used to describe the enhancement effect of the CB particles. The result showed that with the increase of matrix molecular weight, the viscoelasticity of the composites was less sensitive to the CB topology. And the fractal dimension of the CB network in the composites with the low-molar-mass PEO was 2.0±0. 1.