聚偏氟乙烯取向膜在拉伸过程中的晶相变化

PHASE TRANSITION OF ORIENTED POLY(VINYLIDENE FLUORIDE)FILMS UPON STRETCHING

<正> 聚偏氟乙烯(PVF_2)的多晶型、压电和热电性引起人们关注。一般认为PVF_2有α、β、γ、δ4种晶相,另有报道存在一ε相。其中具有压电和热电性的β相最为重要。通常从PVF_2熔体只能获得α相。为了获得β相结晶,人们尝试过很多方法。本文研究拉伸过程中PVF_2结构和晶相的变化。PVF_2为Polysciences产品,MW 1.4×10~5。经熔体拉伸制成厚50nm的取向膜。仪器为H-600型透射电镜,工作电压100kV。以及Alpha Cenfauri付利叶变换红外光谱仪。

Deformation process and phase transition of the oriented films of poly(vinylidene fluoride) (PVF_2) have been investigated by electron microscopy,electron diffraction and FTIR. The films prepared by a melt drawn technique contain highly oriented larnellae, which predominantly consist of a phase. During the course of stretching the fibrillar crystals are formed,accompanied by a α→β phase transition. Increasing deformation temperature is of no advantage to the α→β phase transition.