Electrical and dielectric properties in carbon fiber‐filled LMWPE/UHMWPE composites with different blend ratios
Electrical and dielectric properties in carbon fiber‐filled LMWPE/UHMWPE composites with different blend ratios
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DOI：
10.1002/polb.21371
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发表时间：
2008-02
期刊：
影响因子：
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通讯作者：
Qingyun Chen;Ying Xi;Y. Bin;M. Matsuo
中科院分区：
文献类型：
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作者：
Qingyun Chen;Ying Xi;Y. Bin;M. Matsuo
采用溶液凝胶法和熔融捏合法制备了碳纤维（CF）填充低分子量聚乙烯（LMWPE）和超高分子量聚乙烯（UHMWPE）复合材料。碳纤维的含量固定为23.5体积%。复合材料的电阻率，正温度系数（PTC），和介电行为变得更加明显的LMWPE与高得多的热膨胀比UHMWPE的含量增加。当LMWPE/UHMWPE共混比为9/1时，PTC效应最显著。超过9/1，PTC效应不太明显。扫描电子显微镜（SEM）和差示扫描量热法（DSC）显示，UHMWPE和LMWPE链内的复合材料结晶独立的凝胶化从溶液中，几乎不受碳纤维的存在。因此，证实了对于复合材料（3/1和6/1），碳纤维选择性地定位在LMWPE和UHMWPE的混合区域中，并且对于9/1、12/1和15/1复合材料，主要定位在LMWPE区域中。这表明，对于9/1复合材料，LMWPE区域内的碳纤维含量最高，并且9/1复合材料提供最显著的PTC效应。
Carbon fiber (CF) filled low-molecular-weight polyethylene (LMWPE) and ultra-high molecular weight polyethylene (UHMWPE) composites were prepared by the gelation from solution and the kneading in the melting state. The content of carbon fibers was fixed to be 23.5 vol %. The resistivity, positive temperature coefficient (PTC), and dielectric behaviors of the composites became more pronounced with increasing content of LMWPE with much higher thermal expansion than that of UHMWPE. The PTC effect became most significant, when the blend ratio of LMWPE to UHMWPE was 9/1. Beyond 9/1, the PTC effect was less pronounced. Scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) revealed that the UHMWPE and LMWPE chains within the composite crystallized independently by gelation from solution and were virtually unaffected by the presence of carbon fibers. Consequently, it was confirmed that carbon fibers selectively were localized in the mixed region of LMWPE and UHMWPE for the composite (3/1 and 6/1) and mainly in the region of LMWPE for the 9/1, 12/1, and 15/1 composites. This indicated that the content of carbon fibers within LMWPE region was the highest for the 9/1 composite and the 9/1 composite provides the most significant PTC effect.