Li Xiaoxiao, Wang Shi-Qing
Morton Institutes of Polymer Science and Engineering, University of Akron, Akron, Ohio 44325, United States.
ACS Macro Lett. 2015 Oct 20;4(10):1110-1113. doi: 10.1021/acsmacrolett.5b00554. Epub 2015 Sep 16.
We have carried out a series of tensile extension tests on the two most common polymer glasses to describe their generic mechanical responses as a function of deformation rate at different temperatures. The essentially defect-free polystyrene and poly(methyl methacrylate) both show remarkable re-entrant failure: being ductile at intermediate rates and showing diminishing toughness at both higher and lower rates. We draw phase diagrams to map out the relationship between brittle-like and yield-like states in terms of temperature, rate, and stress. A coherent understanding of the rich phenomenology requires us to describe in more detail the interplay between the chain network and the primary structure bonded by intersegmental van der Waals forces.
我们对两种最常见的聚合物玻璃进行了一系列拉伸试验，以描述它们在不同温度下作为变形速率函数的一般力学响应。基本无缺陷的聚苯乙烯和聚甲基丙烯酸甲酯都表现出显著的重入式失效：在中等速率下具有延展性，而在较高和较低速率下韧性都会降低。我们绘制相图以描绘类脆性状态和类屈服状态之间在温度、速率和应力方面的关系。要对这种丰富的现象学有连贯的理解，就需要我们更详细地描述链网络与由链段间范德华力键合的一级结构之间的相互作用。
