拉伸处理对碳纳米纤维/聚偏氟乙烯复合材料结晶行为和AC导电性能的影响

Effect of stretching process on crystalline structures and alternating current conductivity of CNF/PVDF composites

采用溶液浇铸法制备1%(质量分数,下同)~5%的碳纳米纤维/聚偏氟乙烯(CNF/PVDF)复合材料,并对CNF/PVDF复合材料进行拉伸处理.研究拉伸处理对复合材料的结晶行为以及AC导电率的影响.结果表明:拉伸处理对PVDF的结晶结构有显著影响,使PVDF的α晶型有效地转变为β晶型,同时也会降低PVDF的结晶度.另一方面,拉伸处理会改变CNF在PVDF基体中的分布状态,降低复合材料的AC导电率,使其逾渗阈值由1%提高至3%~5%之间.

Carbon nanofiber(CNF)/poly(vinylidene fluoride)(PVDF)composites with different CNF concentrations from 1%(mass fraction,the same as below)to 5%were prepared into thin films via solution casting method firstly,followed by the stretching process.The effect of stretching process on the crystallization and alternating current(AC)conductivity of CNF/PVDF composites was discussed.The results reveal that the phase transformation fromα-toβ-crystal PVDF can be effectively induced by stretching process.Simultaneously,the crystallinity is decreased.On the other hand,CNFs in PVDF are re-oriented and the AC conductivity of CNF/PVDF composites is decreased,the percolation threshold of which is raised from 1%to a value between 3%and 5%.