摘要
选用HDPE和LLDPE为原料进行熔融共混,通过差示扫描量热(DSC)测试、连续自成核退火(SSA)热分级法探究线型与支化聚乙烯分子的共结晶行为,尤其是采用SSA热分级法剖析了形成共晶的分子链的结构特征,并在此基础上研究共结晶对共混物力学性能的影响。DSC结果表明,HDPE与LLDPE具有较好的相容性且HDPE在共混物结晶过程中具有成核作用。SSA测试显示,HDPE/LLDPE共混物的结晶行为依赖于LLDPE组分的支链分布,只有当LLDPE的亚甲基序列长度与HDPE的链段相互匹配时才会形成共晶。共混物的屈服强度与共混体系的结晶度以及晶片厚度有关。屈服强度与自然拉伸比均随LLDPE质量分数的增加而减小。
Cocrystallization behaviors of HDPE and LLDPE blends were studied via DSC test, and successive selfnucleation and annealing （SSA） thermal fractionation. Specifically i SSA technique was used to analyze the structural characteristics of the cocrystallized molecular chains. The influences of cocrystallization on the mechanical properties of the blends were also discussed. DSC results prove the good compatibility between HDPE and LLDPE in the blend system, and show that HDPE has a nucleation effect on the crystallization of the blends. SSA reveals that the crystallization behavior of HDPE/LLDPE blends depends on the branch distribution of LLDPE. HDPE and LI.I）PE form co-crystal only when their methylene sequence lengths are match. It is found that the yield stress of the blends is related to crystallinity and lamellae thickness. Yield stress decreases linearly with LLDPE content. The natural draw ratio drops with increase of LLDPE content.
出处
《高分子材料科学与工程》
EI
CAS
CSCD
北大核心
2013年第3期115-119,共5页
Polymer Materials Science & Engineering
基金
教育部新世纪优秀人才支持计划(NCET-10-0562)
