纳米SiOx/聚乙烯复合材料强场电导特性的研究

用双溶液共混法制备了不同掺杂浓度的纳米SiOx/低密度聚乙烯(LDPE)复合材料,并利用动态机械谱(DMA)对复合材料的机械性能进行了测量.发现纳米SiOx/LDPE复合材料的玻璃化转变温度,储能模量和机械损耗模量随着纳米氧化硅掺杂浓度的增加先减小后增大,但均大于纯聚乙烯.研究了不同掺杂浓度的纳米SiOx/LDPE聚合物复合材料在293～353K的温度范围内的电导特性.结果表明纯聚乙烯和含有纳米SiOx的复合介质的强场电导不符合Schottky效应和Poole-Frenkel效应.进一步的分析表明,纯聚乙烯试样以空间电荷限制电流为主,而含纳米SiOx的复合介质的强场电导则以离子跳跃电导为主,并且通过实验数据计算了不同温度下载流子的跳跃距离.

High Field Conduction of the Composites of Low-Density Polyethylene / Nano-SiOx

High field conduction of the composite of low-density polyethylene (LDPE)/ nano SiOx and pure polyethylene is studied at various temperatures in detail, as well as the effect of the contents of nano SiOx on high field conduction. At the same time, the mechanical property of samples with various contents of nano-SiOx is also studied with Dynamic Mechanical Analysis (DMA). The storage modulus (E'), the glass transition temperature (Tg) and mechanical loss mudulus (E") of the composite are higher than those of pure polyethylene and vary with nano-SiOx contents in U-shapes. Schottky effect, Poole-Frenkel effect, space-charge-limited conduction (SCLC), and ion hopping conduction are likely to fit our results. It is pointed out that both Schottky effect and Poole-Frenkel effect do not fit well for all of the samples. However, it is found that space-charge-limited conduction fits well for pure LDPE, and ion hopping conduction fits for the composite of LDPE/nano-SiOx. In addition, the hopping distances of the composite at various temperatures are calculated at last.