玻璃纤维对碳纳米管填充聚合物/热塑性聚氨酯共混体系导电性能的影响

研究了表面带有环氧基团的玻璃纤维(GF)对聚丙烯(PP)/热塑性聚氨酯(TPU)/多壁碳纳米管(MWCNT)、 聚甲基丙烯酸甲酯(PMMA)/TPU/MWCNT和聚乳酸(PLA)/TPU/MWCNT体系导电性能的影响. 研究结果表明, 未添加GF时, 由于MWCNTs选择性地分布在TPU分散相中, PP/TPU/MWCNT, PMMA/TPU/MWCNT和PLA/TPU/MWCNT材料的导电性能很差; 加入20%的GF使3个体系的电阻率均大幅度下降, 最高下降约13个数量级, 表明填充GF是一种具有普适性的改善以TPU为分散相的共混体系导电性能的有效方法. GF使体系电阻率降低的机理主要是形成了TPU包覆GF结构, 该结构可以看作长径比较高的导电棒, 可以有效协助导电通路的构建; 同时GF还起到了体积占位的作用, 提高了体系中导电组分在基体中的有效浓度.

Effects of Glass Fiber on Electrical Conductivities of Multiwalled Carbon Nanotube-filled Polymer/Thermoplastic Polyurethane Blends

The effects of epoxy-functionalized glass fiber( GF) on the electrical conductivities of polypropylene ( PP)/thermoplastic polyurethane ( TPU )/multiwalled carbon nanotube ( MWCNT ) , poly ( methyl methacry-late)(PMMA)/TPU/MWCNT and poly(lactic acid) (PLA)/TPU/MWCNT composites were investigated. The electrical resistivities of polymer/MWCNT composites increase with the addition of TPU due to the selective location of MWCNTs in the TPU phase. After the addition of GF, the electrical resistivities of polymer/TPU/MWCNTs composites are significantly reduced by up to 13 orders of magnitude, indicating that the addition of GF is a universal and effective method to improve the electrical conductivities of MWCNTs-filled polymer blends with TPU as the dispersed phase. The mechanism for resistivity reduction of GF-filled system is mainly the formation of TPU coated GF structure which serves as long conductive rod with high aspect ratio, facilitating the construction of conductive paths, although the effective concentration of the conductive species increases because of the volume-exclusion effect of GF. It is found that the contents of GF and MWCNTs are important factors affecting the electrical conductivities of the composites.