DSC法测定PS玻璃化温度的再研究  

GLASS TRANSITION TEMPERATURE OF POLYSTYRENE DETERMINED BY DSC REVISITED

作　　者：刘国栋[1] 张福强[1] 张丽娇[1] 王艳丽[1] 范留彬[1] 

机构地区：[1]河北工业大学高分子科学与工程系,天津300130

出　　处：《高分子学报》2010年第9期1065-1069,共5页Acta Polymerica Sinica

基　　金：国家自然科学基金(基金号20804013);河北省自然科学基金(基金号B2007000019)资助项目

摘　　要：对Fevotte提出的由DSC曲线构建玻璃化温度谱图的方法进行了改进,将橡胶态含量为0.5时的温度定义为聚合物的Tghr.采用改进Fevotte方法重新研究了PS的玻璃-橡胶态转变,PS的Tghr值比半比热外推法结果Tghc高约4K,当考察热处理时间和降温速率对聚合物玻璃-橡胶态转变的影响规律时,改进方法得到的结果与理论分析更为一致.聚合物的Tghr受热历史影响,随热处理条件改变,通过对不同降温速率冷却后样品滞后焓数据的拟合,推测PS样品的Tghr在377.5～390.9K范围内变化.The method of reconstruction histograms of glass transition temperature from differential scanning calorimetry（DSC） thermograms proposed by Fevotte was improved,and the temperature related with half rubbery content Tghr was defined as an new parameter for glass transition.The rubbery fraction was obtained by deduction of the heat flow caused by retardant enthalpy recovery from the recorded DSC heat flow.The revisit of the glass transition behavior of polystyrene（PS） by using the modified Fevotte method was described in this paper.It was found that Tghr of PS is about 4 K higher than that obtained by using the widely used half specific heat capacity（Cp） extrapolated method.The reproducibility of Tg acquired by the modified Fevotte method was improved compared with that using the methods provided by the general commercial software.When the effect of annealing time and cooling rate on glass-rubber transition behavior of PS was investigated,the modified Fevotte method shows its superiority.It was found that Tghr of PS increases monotonously with increasing annealing time and decreasing cooling rate.Polymer with different thermal history usually shows different Tg.Tghr of PS was predicted to be in the range of 377.5 K to 390.9 K depending on physical aging extent.Also it is indicated that the physical aging mode has little effect on polymer Tg.

关 键 词：玻璃化温度 DSC 物理老化 聚苯乙烯 

分 类 号：O631.22[理学—高分子化学]