Linear Stress Relaxation and Probe Reorientation: Comparison of the Segmental Dynamics of Two Glassy Polymers during Physical Aging
Linear Stress Relaxation and Probe Reorientation: Comparison of the Segmental Dynamics of Two Glassy Polymers during Physical Aging
复制标题
DOI：
10.1021/acs.macromol.9b01625
复制
发表时间：
2019-10
期刊：
影响因子：
5.5
通讯作者：
J. Ricci;Trevor Bennin;Enran Xing;Mark Ediger
中科院分区：
文献类型：
--
作者：
J. Ricci;Trevor Bennin;Enran Xing;Mark Ediger
玻璃态聚（甲基丙烯酸甲酯）（PMMA）和聚（乳酸）（PLA）的分段动力学已被测量超过8小时的老化通过光学探针重取向和机械应力松弛实验中进行的线性响应制度，在6和30 K之间的温度范围内低于玻璃化转变温度（Tg）。在所有实验中观察到弛豫时间和老化时间之间的明显幂律关系。对于PLA和PMMA玻璃，探针的重取向时间与应力松弛时间在观察到的范围内的老化时间和老化温度，与两个松弛时间相关的幂律与指数为1.01的强烈相关。这些数据集与以前发表的工作的比较表明，两个弛豫时间之间的关系是不受二次弛豫过程，低水平的交联，或增塑剂的存在下。这些结果支持了探针重定向技术是一种很好的修复方法的观点。
Segmental dynamics of glassy poly(methyl methacrylate) (PMMA) and poly(lactic acid) (PLA) have been measured over 8 h of aging via both optical probe reorientation and mechanical stress relaxation experiments performed in the linear response regime, in a temperature range between 6 and 30 K below the glass transition temperature (Tg). A clear power law relationship between relaxation times and aging times is observed in all experiments. For both PLA and PMMA glasses, the probe reorientation times are strongly correlated with stress relaxation times over the observed range of aging times and aging temperatures, with the two relaxation times related by a power law with an exponent of ∼1. Comparisons of these data sets with previously published work indicate that the relationship between the two relaxation times is not influenced by secondary relaxation processes, low levels of crosslinking, or the presence of a plasticizer. These results support the view that the probe reorientation technique is a good repo...