Polystyrene Glasses under Compression: Ductile and Brittle Responses

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• 作者：Jianning Liu ; Panpan Lin ; Shiwang Cheng ; Weiyu Wang ; Jimmy W. Mays ; Shi-Qing Wang
• 刊名：ACS Macro Letters
• 出版年：2015
• 出版时间：October 20, 2015
• 年：2015
• 卷：4
• 期：10
• 页码：1072-1076
• 全文大小：331K
• ISSN：2161-1653

文摘

Polystyrene of different molecular weights and their binary mixtures are studied in terms of their various mechanical responses to uniaxial compression at different temperatures. PS of M_w = 25 kg/mol is completely brittle until it is above its glass transition temperature T_g. In contrast, upon incorporation of a high molecular weight component, PS mixtures turn from barely ductile a few degrees below its T_g to ductile over 40掳 below T_g. In the upper limit, a PS of M_w = 319 kg/mol yields and undergoes plastic flow, even at T = 鈭?0 掳C. The observed dependence of mechanical responses on molecular weight and molecular weight distribution can be adequately rationalized by the idea that yielding and plastic compression are caused by chain networking.