Molecular Chain Movements and Transitions of SEBS above Room Temperature Studied by Moving-Window Two-Dimensional Correlation Infrared Spectroscopy

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• 作者：Tao Zhou ; Aiming Zhang ; Changsheng Zhao ; Hongwen Liang ; Zhiyong Wu ; Jingkui Xia
• 刊名：Macromolecules
• 出版年：2007
• 出版时间：December 11, 2007
• 年：2007
• 卷：40
• 期：25
• 页码：9009 - 9017
• 全文大小：651K
• 年卷期：v.40,no.25(December 11, 2007)
• ISSN：1520-5835

文摘

The temperature-dependent molecular chain movements and transitions of polystyrene-block-poly(ethylene-co-1-butene)-block-polystyrene block copolymer (SEBS) above room temperature were studied by in-site infrared spectroscopy combined with moving-window two-dimensional (MW2D) correlation spectroscopy.Some complex molecular chain movements and transitions of SEBS were revealed with the linear incrementaltemperature increasing (30-166 C). The melting point of the extraordinary weak crystal of -(CH₂-CH₂)-_n inthe poly(ethylene-co-1-butene) block (EB) is determined at 48 C. The heat enthalpy relaxation of polystyreneblock (S) of SEBS, which is induced by the framework movement of the side benzene ring and the melting ofthe weak crystal in the polystyrene block, is observed around 72-80 C from the MW2D correlation spectrum.The glass transition temperature of the polystyrene block is determined around 120 C. From the MW2D correlationspectrum, we discover that, around 120 C, the chain segment movement of polystyrene block occurs before thatof poly(ethylene-co-1-butene) block in phase interface. At 142 C, the fundamental chains of the disperse phase(S block) center initiate to entirely move and this type of movement drives a fraction of the disperse phase (Sblock) to deform from an incomplete shape to a sphere. This corresponds to the entirely viscous flow temperatureof the fundamental chains of the disperse phase.