Self-nucleation and enhanced nucleation of polyvinylidene fluoride (alpha-phase)

The nucleation phenomena of poly(vinylidene fluoride) in its alpha -phase ( alpha -PVDF) are investigated. Self-seeding first investigated helps establ ish a so-called 'efficiency scale', which in turn helps rate the nucleation induced by crystalline additives, and notably PTFE. The thermal and nuclea tion behavior of alpha -PVDF is significantly dependent on its microstructu re. Samples with higher head-to-head inversions display a significant 'memo ry effect': their initial spherulitic morphology is maintained in successiv e recrystallizations. The nucleation density can be increased by addition o f nucleating agents: PTFE or flavanthrone. The nuclei densities reached are , however, nearly two orders of magnitude lower than for isotactic polyprop ylene. These results serve as a basis for a companion investigation of the nucleation of blends of PVDF and polyacrylic polymers, the structural chara cteristics and properties of which can be significantly modified by enhanci ng nucleation. (C) 2001 Elsevier Science Ltd. All rights reserved.