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首页> 外文期刊>Journal of Applied Polymer Science >Origin of stress and birefringence generation at hot-stretching of poly(methyl methacrylate) containing low-molecular-weight compound
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Origin of stress and birefringence generation at hot-stretching of poly(methyl methacrylate) containing low-molecular-weight compound

机译：含有低分子量化合物的聚（甲基丙烯酸甲酯）热拉伸的应力和双折射产生的起源

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摘要

The simultaneous measurements of stress and birefringence during hot-stretching, and after the cessation of stretching, were performed using a miscible blend of poly(methyl methacrylate) (PMMA) and 10 wt% of 4-cyano-4 '-pentylbiphenyl (which is commonly known as 5CB). The birefringence of the blend exhibited anomalous behavior during stretching, that is, it initially decreased, then rapidly increased to a positive value. A concave curve with a minimum birefringence was prominent at low temperatures, during which PMMA determined birefringence. After passing the yield point, which corresponded to the minimum birefringence, the birefringence increased in proportion to the applied stress. That is to say, the stress-optical coefficient remained constant. In this region, the 5CB molecules oriented themselves with the PMMA chains, that is, there was nematic interaction. After stretching ceased, the stress initially decreased rapidly; during this period, the stress-optical coefficient was determined mainly by the deformation of PMMA, that is, glassy component. Subsequently, the orientation relaxation of 5CB, which occurred with the orientation relaxation of PMMA chains in the stage with a long time region, determined the birefringence. These results demonstrated that nematic interaction does not occur when inelastic deformation is governed.
机译：使用聚甲基丙烯酸甲酯（PMMA）和10 wt%的4-氰基-4'-戊基联苯（通常称为5CB）的可混溶混合物，同时测量热拉伸期间和停止拉伸后的应力和双折射。共混物的双折射在拉伸过程中表现出异常行为，即先降低，然后迅速增加到正值。在低温下，具有最小双折射的凹曲线是显著的，在此期间，PMMA决定了双折射。通过屈服点（对应于最小双折射）后，双折射随外加应力成比例增加。也就是说，应力光学系数保持不变。在这个区域，5CB分子与PMMA链定向，即存在向列相互作用。拉伸停止后，应力最初迅速降低；在此期间，应力光学系数主要由PMMA的变形决定，即玻璃态成分。随后，5CB的取向弛豫，即PMMA链在长时间区域的取向弛豫，决定了双折射。这些结果表明，当非弹性变形受到控制时，不会发生向列相相互作用。

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