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 below T-g. In the upper limit, a PS of M-w = 319 kg/mol yields and undergoes plastic flow, even at T = -70 degrees 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.
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机译：研究了不同分子量的聚苯乙烯及其二元混合物在不同温度下对单轴压缩的各种机械响应。 M-w = 25 kg / mol的PS完全脆，直到其高于其玻璃化转变温度T-g。相反，当掺入高分子量组分时，PS混合物从低于其T-g几度的几乎延展性转变为低于T-g 40倍的延性。在上限时，即使在T = -70摄氏度下，Mw = 319 kg / mol的PS仍会产生塑性流动。所观察到的机械响应对分子量和分子量分布的依赖性可以通过以下思想得到充分合理化：屈服和塑性压缩是由链状网络引起的。
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