材料科学
甲基丙烯酸甲酯
高分子化学
量子纠缠
马来酸酐
苯乙烯
放松(心理学)
聚甲基丙烯酸甲酯
玻璃化转变
分子动力学
动力学
旋节分解
相(物质)
化学工程
聚合物
共聚物
复合材料
化学
有机化学
计算化学
物理
工程类
量子
社会心理学
量子力学
心理学
作者
Yu Lin,Yonggang Shangguan,Min Zuo,Eileen Harkin‐Jones,Qiang Zheng
出处
期刊:Polymer
[Elsevier]
日期:2012-03-01
卷期号:53 (6): 1418-1427
被引量:29
标识
DOI:10.1016/j.polymer.2012.01.039
摘要
Poly(methyl methacrylate)/poly(styrene-co-maleic anhydride) (PMMA/SMA) blends with various compositions were prepared through solution casting and melt blending. Two preparation routes, solution casting and melt blending, were used to achieve different degrees of molecular entanglement in the samples with solution casting giving rise to a lower degree of entanglement. Therefore, the effect of molecular entanglement on molecular dynamics and phase-separation kinetics of PMMA/SMA blends was investigated by using broadband dielectric spectroscopy and small-angle laser light scattering (SALLS). Molecular entanglement is found to have a pronounced effect on the α-relaxation process. The glass transition temperature (Tg) is related to the degree of entanglement and a higher degree of entanglement can result in a higher Tg which shifts to a higher temperature after annealing. The relaxation time (τ) of the α-relaxation process is lower for lower degrees of entanglement. Neither the dynamics nor the distribution width of the β-relaxation process is affected by degree of entanglement, regardless of the blend composition. The kinetics of phase-separation by spinodal decomposition (SD) in PMMA/SMA blends are however significantly influenced by the degrees of entanglement with decomposition rate being higher at lower degrees of entanglement.
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