【摘要】 连续自成核退火热分级法(SSA)具有制样简单、无需溶剂、测试耗时较短、设备较廉价等优点,在乙烯/α-烯烃共聚物等领域取得了广泛的应用,是表征其分子结构规整性分散情况的有力研究方法,但它在等规聚丙烯(iPP)方面的应用较少。本文深入研究了iPP的自成核结晶熔融行为,得到了iPP自成核行为的温度范围,并在此基础上深入研究了SSA热分级法的各个条件(首个自成核温度Ts1、在自成核温度(Ts)的停留时间、相邻Ts温度间隔ΔT、SSA分级温度范围等)对最终SSA热分级能力、分级时间的影响,建立了SSA热分级的实验条件与分级效率、分级能力之间的联系。结果表明,对于多数iPP来说,理想的SSA热分级条件为:Ts1=167℃,ts=15min,ΔT=4℃,升降温速率=20℃/min,热分级温度范围167～139℃。其中,扫描温度范围对分级效率的影响最大。对于具有不同规整度的PP来说,须有针对性选择上述关键参数,才能达到分级效率与分级能力的平衡。更多还原

【Abstract】 Owning to the advantages such as easy-sampling,free of solvent,high efficiency and relative low cost of the required instruments,Successive Self-nucleation and Annealing(SSA) fractionation has been widely applied in the analysis of ethylene/α-olefin copolymers.However,it has rarely been successfully applied in the analysis of PP.In this study,the self-nucleation behavior of PP had been studied.Based on the results,obtained,a SSA thermal protocol for iPP was designed,and the influence of important parameters(the first thermal treatment temperature Ts1;holding time ts;temperature gap between adjacent Ts,ΔT;fractionation temperature region) on the fractionation results and efficiency,were thoroughly studied.The results showed that,for iPP samples,the optimal thermal parameters are Ts1=167℃,ts=15min,ΔT=4℃,cooling/heating rate=20℃/min,fractionation temperature region=167-139℃.The variation of fractionation temperature region plays a most important role in determining the efficiency of SSA.For iPP with different tacticity,one must flexibly modify the parameters above,to achieve a balance between efficiency and fractionation results.更多还原