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。
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/a-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, AT; fractionation temperature region） on the fractionation results and efficiency, were thoroughly studied. The results showed that, for iPP samples, the optimal thermal parameters are T51 --167℃, ts = 15min, AT= 4℃, cooling/heating rate= 20℃/min, fractionation temperature region = 167- 139＂C. 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.
出处
《高分子通报》
CAS
CSCD
北大核心
2013年第9期168-176,共9页
Polymer Bulletin
