Crack healing in poly(methyl methacrylate) induced by co-solvent of methanol and ethanol
Crack healing in poly(methyl methacrylate) induced by co-solvent of methanol and ethanol
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DOI：
10.1016/s0032-3861(00)00407-9
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发表时间：
2001-02-01
期刊：
影响因子：
4.6
通讯作者：
Lee, S
中科院分区：
文献类型：
--
作者：
Hsieh, HC;Yang, TJ;Lee, S
研究了聚甲基丙烯酸甲酯（PMMA）经甲醇和乙醇混合溶剂处理后的裂纹愈合。在PMMA中的溶剂混合物的质量传输是异常的，它是混合情况I和情况II传输。质量输运的数据可以用哈蒙模型进行分析。结果发现，混合物的情况I和情况II传输的活化能等于甲醇和乙醇的相应量的总和，每个权重因子基于各自的体积分数。混合物的溶解度等于甲醇和乙醇的溶解度之和，其加权因子基于它们的分子量。基于形貌和机械强度分析了包括润湿和扩散阶段的溶剂愈合。裂纹闭合速率在润湿阶段是恒定的。比较质量输运和裂纹闭合速率的激活能，裂纹尖端的后退是由第二类输运控制。从侧面和顶视图观察到裂纹尖端凹陷。随着乙醇体积分数的降低，试样的机械强度增加。提供断口分析作为机械强度恢复的证据。(C)2000爱思唯尔科技有限公司版权所有。
The crack healing of poly(methyl methacrylate)(PMMA) treated with a solvent mixture of methanol and ethanol was studied. The mass transport of the solvent mixture in PMMA is anomalous; it is mixed Case I and Case II transport. The data of mass transport can be analyzed by Harmon's model. It was found that the activation energies of Case I and Case II transport of mixture are equal to the summation of the corresponding quantities for methanol and ethanol with each weight factor based on the respective volume fraction. The solubility of the mixture is equal to the summation of solubilities of methanol and ethanol with weighting factor based on their molecular weight. The solvent healing including wetting and diffusion stages was analyzed based on the morphology and mechanical strength. The crack closure rate is constant during the wetting stage. Comparing the activation energies of both mass transport and crack closure rate, the crack tip recession is controlled by Case II transport. Crack tip recession was observed from both lateral and top views. The mechanical strength of the healed specimen increases with decreasing volume fraction of ethanol. Fractography was provided as evidence of recovery of mechanical strength. (C) 2000 Elsevier Science Ltd. All rights reserved.