Determination of the α, β, and γ crystalline phases of poly(vinylidene fluoride) films prepared at different conditions
Determination of the α, β, and γ crystalline phases of poly(vinylidene fluoride) films prepared at different conditions
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DOI：
10.1002/app.23137
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发表时间：
2006-05-15
影响因子：
3
通讯作者：
Gregorio, R
中科院分区：
文献类型：
--
作者：
Gregorio, R
在不同的结晶条件下，得到了含有聚偏氟乙烯α、β和伽马三种晶相的样品。通过从二甲基甲酰胺(DMF)溶液中在60℃下结晶获得了完全含有无取向β相的样品，通过在80℃下对原来的a相样品进行单轴拉伸获得了取向β相。在室温下，通过熔化和后冷却获得了只含α相的样品。在164℃下熔融结晶16和36h，得到了同时含有α相和伽马相的样品，用傅立叶变换红外光谱(FTIR)、差示扫描量热仪(DSC)、广角X射线散射(WAXD)、偏光显微镜(PLOM)和扫描电子显微镜(SEM)证实了样品中晶相的存在。红外吸收带明确地识别了样品中贝塔和伽马相的存在。结果表明，无论使用哪种溶剂，T<；70℃的溶液结晶都会产生β相。还测定了各相的熔融温度。(C)2006年威利期刊公司。
Samples containing the three crystalline phases of poly(vinylidene fluoride), alpha, beta, and gamma, have been obtained under distinct crystallization conditions. Samples containing exclusively unoriented beta phase have been obtained by crystallization from dimethylformamide (DMF) solution at 60 degrees C. Oriented beta phase has been obtained by uniaxial drawing, at 80 degrees C, of an originally a phase sample. Samples containing exclusively alpha phase have been obtained by melting and posterior cooling at room temperature. Samples containing both alpha and gamma phases have been obtained by melt crystallization at 164 degrees C for 16 and 36 h. Presence of the crystalline phases in each sample were confirmed by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), wide-angle X-ray scattering (WAXD), polarized light optical microscopy (PLOM), and scanning electron microscopy (SEM). Infrared absorption bands identifying unequivocally the presence of beta and gamma phases in a sample are presented. It is shown that solution crystallization at T < 70 degrees C always results in the beta phase, regardless of the solvent used. Melt temperatures of the respective phases have also been determined. (c) 2006 Wiley Periodicals, Inc.