热处理对聚偏氟乙烯-酰胺类溶剂所制薄膜结晶行为的影响

THE EFFECT OF ANNEALING TEMPERATURE ON CRYSTALLIZATION OF POLY(VINYLIDENE FLUORIDE)FILMS PREPARED FROM POLY(VINYLIDENE FLUORIDE)/AMIDE SOLUTION

使用红外光谱和偏光显微镜对PVDF（聚偏氟乙烯）-DMF（N，N-二甲基甲酰胺）和PVDF-DMAc（N，N-二甲基乙酰胺）体系结晶行为的研究表明，PVDF薄膜的结晶受制备溶剂，后期热处理温度和膜厚度等因素的影响；升高温度，β相含量减小；当温度低于90℃时，PVDF—DMF体系的F（β）值较DMAc体系大，在90～160℃之间则相反，且两种体系的F（β）值分别在约90℃和80℃发生“突变”；同时，结晶还明显受到薄膜厚度的影响，厚度大，结晶较完善．

The crystallization of poly（vinylidene fluoride） （PVDF） films prepared from dimethylformamide （DMF） and dimethylacetamide （DMAc） solution and subsequently annealed at various temperature was studied by FT-IR and optical microscope. The results indicate that the crystallization of PVDF film depends on solvent, annealing temperature and film thickness. For all samples the content of β phase, F （β）, decreases with elevating annealing temperature. When the annealing temperature is less than 90℃ , the F （β） of PVDF-DMF system is higher than that of PVDF-DMAc system; however, at 90 - 160℃, a reversed observation is obtained. For the two systems, interestingly, the F （β） decreases drastically at the region of ca 90℃ and 80℃, respectively. In addition, the crvstallization of PVDF is also affected by film thickness, higher film thickness will make the spherulite more resolved.