Rheology and Structure of Molten, Olefin Multiblock Copolymers
Rheology and Structure of Molten, Olefin Multiblock Copolymers
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DOI：
10.1021/ma1012122
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发表时间：
2010-07
期刊：
影响因子：
5.5
通讯作者：
Heon E. Park;J. Dealy;G. Marchand;Jian Wang;Sheng Li;R. Register
中科院分区：
文献类型：
--
作者：
Heon E. Park;J. Dealy;G. Marchand;Jian Wang;Sheng Li;R. Register
用流变学、差示扫描量热法（DSC）和小角X射线散射法（SAXS）研究了一种新开发的烯烃多嵌段共聚物的几个样品。该合成涉及链穿梭剂（CSA），其在两种催化剂之间切换生长的链，一种催化剂有利于α-烯烃共聚单体的掺入，另一种催化剂抑制掺入。这些数据用于确定辛烯共聚单体含量和CSA水平对熔体中的流变行为和中间相分离转变（MST）的发生的影响。为了区分结晶和MST，我们进行了量热扫描，并在一定温度范围内测量了密度和流变性能。小角X射线散射分析的样品，经历了平面拉伸流显示强烈的排列层状介晶畴，保持其对齐退火后。这一结果证实了基于流变学证据的假设，即层状中间相是在熔体中形成的。
Several samples of a recently developed olefin multiblock copolymer were studied by means of rheology, differential scanning calorimetry (DSC) and small-angle X-ray scattering (SAXS). The synthesis involves a chain shuttling agent (CSA) that switches the growing chain between two catalysts, one that favors the incorporation of an α-olefin comonomer and one that suppresses incorporation. The data were used to determine the effect of octene comonomer content and CSA level on rheological behavior and the occurrence of mesophase separation transition (MST) in the melt. To distinguish between crystallization and MST, we made calorimetry scans and measured the density and rheological properties over a range of temperatures. Small angle X-ray scattering analysis of a sample that had undergone planar extensional flow revealed strong alignment of lamellar mesodomains, which maintained their alignment after annealing. This result confirmed the hypothesis based on rheological evidence that a lamellar mesophase is pr...