Microstructure and mechanical properties of semicrystalline-rubbery-semicrystalline triblock copolymers
Microstructure and mechanical properties of semicrystalline-rubbery-semicrystalline triblock copolymers
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DOI：
10.1021/ma0501794
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发表时间：
2005-07-12
期刊：
影响因子：
5.5
通讯作者：
Bates, FS
中科院分区：
文献类型：
--
作者：
Koo, CM;Wu, LF;Bates, FS
研究了一系列 M-n = 27-372 kg/mol 的对称 EPE（E = 聚（乙烯-1-丁烯）和 P = 聚（乙烯-丙烯））三嵌段共聚物的固态微观结构和机械性能。 EPE 三嵌段共聚物的微相分离源自 (i) 在高总分子量结晶之前熔体中化学不相容性诱导的微相分离，或 (ii) 在低总分子量下从均匀熔体中结晶诱导的微相分离。小角 X 射线散射表明，这些 EPE（f(E) 近似于 f(p) 近似于 0.5）在研究的分子量范围内采用层状形态。观察到的层间域间距 (d) 与分子量成比例，d 类似于 N-0(β)，其中 No 是聚合度，对于结晶诱导的偏析，β = 0.22，对于微相分离熔体，β = 0.63。微相分离模式强烈影响层状结构内聚乙烯微晶的链折叠微观结构。讨论了这些观察结果对这些材料的极限拉伸强度的影响。
Microstructure of and mechanical proper-ties of a series of symmetric EPE (E = poly(ethylene-co-1-butene) and P = poly(ethylene-alt-propylene)) triblock copolymers with M-n = 27-372 kg/mol have been investigated in the solid state. Microphase separation of EPE triblock copolymers originates from either (i) chemical incompatibility-induced microphase separation in the melt before crystallization at high overall molecular weights or (ii) crystallization-induced microphase separation from a homogeneous melt at low overall molecular weights. Small-angle X-ray scattering demonstrates that these EPEs (f(E) approximate to f(p) approximate to 0.5) adopt a lamellar morphology over the range of molecular weights studied. The observed interlamellar domain spacing (d) scales with the molecular weight as d similar to N-0(beta), where No is the degree of polymerization and beta = 0.22 for crystallization-induced segregation and beta = 0.63 for microphase-separated melts. The mode of microphase separation strongly affects the chain folding microstructure of the polyethylene crystallites within the lamellar structure. The consequences of these observations on the ultimate tensile strengths of these materials are discussed.