降温速率对偏氟乙烯-三氟乙烯共聚物相转变的影响Effect of Cooling Rate on the Phase Transition of P(VDF-TrFE) Copolymer
葛锋;王雪梅;冉祥海;
摘要(Abstract)：
系统研究了降温速率对偏氟乙烯-三氟乙烯共聚物(P(VDF-Tr FE))相转变行为的影响。结果表明,P(VDFTr FE)的DSC降温曲线上存在结晶峰及居里相转变峰。居里相转变过程为一阶相变,包含两个过程:(1)高温居里相转变,具有较少旁氏构象缺陷结构的极性低温相(LT)向非极性高温相(HT)转变;(2)低温居里相转变,长程全反式构象被无规旁氏构象打乱的冷却相(CL)向HT转变。随着降温速率的提高,HT-to-CL和HT-to-LT的转变温度降低,但转变焓值及HT-to-CL与HT-to-LT转变焓的比值均增大,说明降温速率越快越有利于极性相,尤其是CL相的形成。在随后的升温过程中,CL-to-HT的转变温度随着降温速率的提高而升高,而LT-toHT的相转变温度几乎不变,说明在降温过程中形成CL相的规整度随降温速率的提高而增大。而HT相的熔融温度及熔融焓随降温速率的提高而减小,说明样品在降温过程中没有足够的时间完成结晶,且结晶尺寸减小。由此可以得出,快速降温不利于非极性相HT的形成,但有利于极性相(CL、LT),尤其是CL相的形成。
关键词(KeyWords)： 偏氟乙烯-三氟乙烯共聚物;相转变;晶态结构;降温速率
基金项目(Foundation): 国家自然科学基金项目(21504091)
作者(Authors): 葛锋;王雪梅;冉祥海;
DOI: 10.15925/j.cnki.issn1005-3360.2018.11.009
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