How Melt-Stretching Affects Mechanical Behavior of Polymer Glasses
How Melt-Stretching Affects Mechanical Behavior of Polymer Glasses
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DOI：
10.1021/ma300955h
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发表时间：
2012-08
期刊：
影响因子：
5.5
通讯作者：
Gregory D. Zartman;Shiwang Cheng;Xin Li;Feiyue Lin;M. Becker;Shi‐Qing Wang
中科院分区：
文献类型：
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作者：
Gregory D. Zartman;Shiwang Cheng;Xin Li;Feiyue Lin;M. Becker;Shi‐Qing Wang
这项工作需要一个简单的现象学方法的问题，何时，如何，以及为什么脆性聚合物玻璃变成韧性，反之亦然。将聚合物玻璃视为杂化物，我们认识到通过货车德瓦尔斯力（网络1）和链网络（即，玻璃化缠结网络）（网络2）必须在机械响应的任何讨论中考虑。为了证明这一观点的好处，我们首先进行了定义明确的熔融拉伸实验在四个常见的聚合物玻璃（PS，PMMA，SAN和PC）在一个系统的方式，无论是在一个固定的Hencky应变速率到给定程度的拉伸在几个温度下，或在一个给定的温度下，以不同的拉伸水平，使用相同的Hencky速率。然后，我们试图通过快速热淬灭来保持熔体拉伸对链网络结构的影响。这些熔融拉伸的无定形聚合物随后的室温拉伸延伸揭示了一些普遍的东西：（a）沿着th.
This work takes a simple phenomenological approach to the questions of when, how, and why a brittle polymer glass turns ductile and vice versa. Perceiving a polymer glass as a hybrid, we recognize that both the primary structure formed by van der Waals forces (network 1) and chain network (i.e., the vitrified entanglement network) (network 2) must be accounted for in any discussion of the mechanical responses. To show the benefit of this viewpoint, we first carried out well-defined melt-stretching experiments on four common polymer glasses (PS, PMMA, SAN, and PC) in a systematic way either at a fixed Hencky strain rate to a given degree of stretching at several temperatures or at a given temperature to different levels of stretching using the same Hencky rate. Then we attempted to preserve the effect of melt-stretching on the chain network structure by rapid thermal quenching. Subsequent room-temperature tensile extension of these melt-stretched amorphous polymers reveals something universal: (a) along th...