Mechanical behaviour of poly(methyl methacrylate)
Mechanical behaviour of poly(methyl methacrylate)
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DOI：
10.1007/bf01045745
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发表时间：
1990-04
影响因子：
4.5
通讯作者：
W. Cheng;G. Miller;J. Manson;R. Hertzberg;L. Sperling
中科院分区：
文献类型：
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作者：
W. Cheng;G. Miller;J. Manson;R. Hertzberg;L. Sperling
使用商品聚甲基丙烯酸甲酯(PMMA)在不同温度和加载速率下进行了一系列拉伸和三点弯曲研究。获得了不同条件下的拉伸性能和断裂韧性数据。一般情况下，拉伸强度和断裂韧性都随着加载速率的增加和温度的降低而增加，但当温度达到玻璃化转变区时，断裂韧性与加载速率和温度之间的关系变得非常复杂。这种行为是粘弹性和局部塑性变形同时作用的结果。在玻璃化转变区，断裂机制由脆性破坏转变为延性破坏。由拉伸试验建立的破坏包络表明，玻璃PMMA在没有破坏的情况下可以承受的最大延伸率约为130%。计算的表观活化能表明，热塑性聚合物(至少是聚甲基丙烯酸甲酯)的破坏过程遵循粘弹性过程，无论是玻璃化转变还是β转变。前者是需要裂纹萌生的情况。
A series of tensile and three-point bending studies was conducted at various temperatures and loading rates using a commercial poly(methyl methacrylate) (PMMA). Tensile properties and fracture toughness data were obtained for the various conditions. In general, both tensile strength and fracture toughness increase with increasing loading rate and decreasing temperatur E. However, when the temperature reaches the glass transition region, the relationships between fracture toughness, loading rate, and temperature become very complex. This behaviour is due to the simultaneous interaction of viscoelasticity and localized plastic deformation. In the glass transition region, the fracture mechanism changes from a brittle to a ductile mode of failure. A failure envelope constructed from tensile tests suggests that the maximum elongation that the glassy PMMA can withstand without failure is about 130%. The calculated apparent activation energies suggest that the failure process of thermoplastic polymers (at least PMMA) follows a viscoelastic process, either glass orβtransition. The former is the case if crack initiation is required.