PBT/PTT合金的非等温结晶行为

采用差示扫描量热法(DSC)研究了聚对苯二甲酸丁二酯(PBT)/聚对苯二甲酸丙二酯(PTT)合金的非等温结晶动力学.随着降温速率的增大,PBT/PTT合金的结晶峰温均降低,结晶峰均加宽.采用Jeziorny法、莫志深法和Flyn-Wall-Ozawa法分析非等温结晶过程,Jeziorny法能够描述PBT/PTT合金的初期结晶过程,对后期结晶存在一定偏差,各PBT/PTT合金的结晶维数变化不大；莫志深和Flyn-Wall-Ozawa法能很好地描述PBT/PTT合金的非等温结晶过程,随PTT含量增加,由Flyn-Wall-Ozawa法求得PBT/PTT合金的活化能呈增加趋势.相对结晶度为0.5,m(PBT)/m(PTT)分别为90∶10,70∶30,50∶50时,PBT/PTT合金的活化能分别为-201.9,-116,0,-66.6 kJ/mol;相对结晶度为0.5时,m(PBT)/m(PTT)为50∶50的合金活化能比PTT(-77.4 kJ/mol)还高.

Non-isothermal crystallization kinetics of PBT/PTT alloys

The non-isothermal crystallization of polybutylene terephthalate(PBT)/polytrimethylene terephthalate(PTT) alloys was studied by differential scanning calorimetry(DSC).The alloys′ crystallization peak temperature decreased and crystallization peak became wider as the cooling rate increased.The non-isothermal crystallization of the alloy was analyzed by Jeziorny method,Mo method and Flyn-Wall-Ozawa(FWO) method.Jeziorny method could describe the initial stage of the crystallization process of the alloys though caused some deviation in analyzing the late stage of the crystallization process;the crystallization dimension n calculated by Jeziorny equation varied barely.Non-isothermal crystallization process of the alloys could be properly described by Mo equation and FWO method as well.The alloys′ activation energy calculated by FWO method assumed an increasing trend as the PTT content rose.When the molar ratio of PBT to PTT was 90 ∶ 10,70 ∶ 30,50 ∶ 50,respectively,and the relative crystallinity was 0.5,the alloys had activation energy of-201.9,-116.0,-66.6 kJ/mol,respectively.The alloy with molar ratio of 50 ∶ 50 even possessed a higher activation energy than pure PTT(-77.4 kJ/mol) in case the relative crystallinity remained to be 0.5.