Interdiffusion at Homopolymer/Random Copolymer Interfaces Investigated by Energy-Filtering Transmission Electron Microscopy

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• 作者：Yonggui Liao ; Ayumi Nakagawa ; Shin Horiuchi ; Toshiaki Ougizawa
• 刊名：Macromolecules
• 出版年：2007
• 出版时间：October 30, 2007
• 年：2007
• 卷：40
• 期：22
• 页码：7966 - 7972
• 全文大小：585K
• 年卷期：v.40,no.22(October 30, 2007)
• ISSN：1520-5835

文摘

Interdiffusion and welding behaviors of a miscible pair of poly(methyl methacrylate)/poly(styrene-ran-acrylonitrile) (PMMA/SAN) laminates were investigated by energy-filtering transmission electron microscopy(EFTEM) and asymmetric double beam cantilever (ADBC) test. The composition variations across the interfaceswere investigated using oxygen and nitrogen elemental maps and by electron energy loss spectroscopy. Thecomposition profiles exhibited two-step gradients with a minimum gradient at the midpoint of the interfacialregion. Welding experiments by ADBC test also showed an unusual toughness-thickness relationship where thetoughness continued to increase even in the interfacial regions that are significantly thicker than the size ofentanglement spacing. Both EFTEM analysis and ADBC test indicated that during the interdiffusion process theinterfacial layer develops into entanglement structures that are mechanically more stable. The combination ofEFTEM and ADBC tests provided us with a better understanding of the interfacial structures includingentanglements.