拉伸工艺对聚偏氟乙烯薄膜结晶特性的影响

Effect of stretching technology on crystalline characteristic of PVDF thin films

采用挤出法制备了PVDF片材;利用单轴拉伸工艺制备了β相含量相对较高的聚偏氟乙烯(PVDF)薄膜;采用偏光显微镜、差示扫描测试仪、X射线衍射仪等仪器,分析了拉伸过程中PVDF薄膜的形貌、结晶度以及结构变化,讨论了不同拉伸温度、不同拉伸比以及不同拉伸速率对薄膜微观结构及β相相对含量的影响。结果表明:PVDF薄膜拉伸过程中α相受外力作用转变成β相。PVDF挤出片材在拉伸温度80℃、拉伸比5倍,拉伸速率50mm/min条件下进行拉伸时,薄膜中β相的相对含量可高达57%。

PVDF thick films were prepared by extruding.PVDF films with high β phase relative content were prepared by uniaxial stretching.Polarizing microscope,DSC and XRD were used to analyse the changes of morphology,crystallinity and structure of PVDF films during the stretching process.Effects of different stretching temperature,stretching ratio R and stretching rate on the microstructure of films and the relative content of the β phase were discussed.Result showed that α phase in PVDF films was converted to β phase under external force during the stretching process.The relative content of β phase in film can be up to 57% when the films were stretched 5 times at the stretching rate of 50 mm/min and at 80℃.