拉伸工艺对聚偏二氟乙烯结构性能的影响

The Influence of Various Drawing Conditions on the Structure and Properties of Polyvinylidene Fluoride

用熔融热压法和溶液浇铸法制备聚偏二氟乙烯初始膜，在２５ ～１１０ ℃下进行不同形变量的拉伸．结果表明，拉伸促使初始膜中的球晶α相向片晶β相转变．降低拉伸温度，增大拉伸比，可增大相变量．高温高拉伸比还可促使非晶相向β相转变，增大β相含量，从而提高压电性能．拉伸及退火均使薄膜电击穿强度明显提高．

Polyvinylidene fluoride original films are produced by solvent and melt cast methods, and are drawn with various drawing rations in 25-110?℃. The results show that drawing can make α spherulitic crystallites transform into β lamella crystallites. Low temperature and high drawing ratio increase the content of the transition. After α crystallites are wholly transformed, higher temperature and higher drawing ratio can induce some non crystallites to transform into β crystallites, then the content of β phase is increased and so its piezoelectricty is improved. After drawing, the electrical breakdown strength of PVDF film increases at a large scale and also after annealing.