Study of crystal structure and properties of poly(vinylidene fluoride)/graphene composite fibers

Poly(vinylidene fluoride) (PVDF) nascent composite fibers were prepared through the melt-spinning method with different graphene (GE) contents, following which post-stretched composite fibers were obtained using a post-stretching process under thermal treatment condition. The effects of GE content and post-stretching ratio on the crystal structure and properties of the fibers were investigated in order to obtain PVDF composite fibers with high beta crystal content and high hydrophobicity and oleophilicity. The results indicated that the addition of GE led to some extent to an improvement in the content of beta crystals and the orientation of crystals. Furthermore, the addition of GE obviously improved the mechanical properties, hydrophobicity and oleophilicity of nascent composite fibers. The post-stretching ratio had a significant influence on the transition of the crystal phase from alpha to beta and the orientation of crystals. In addition, the post-stretching played a positive role in enhancement of mechanical properties and hydrophobicity. When 5 wt% GE was added and the post-stretching ratio was 6, PVDF composite fibers with high beta crystal content, super-oleophilicity and high hydrophobicity could be obtained. The beta crystal content of PVDF composite fibers could reach 62.8%, oil contact angle was 0 degrees and water contact angle was 116.0 degrees. (c) 2021 Society of Industrial Chemistry.