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

Abstract

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 from α- to β-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%.

Keywords

• cnf
• pvdf
• stretching
• crystallization
• ac conductivity