Revisiting the glass transition and dynamics of supercooled benzene by calorimetric studies.
Revisiting the glass transition and dynamics of supercooled benzene by calorimetric studies.
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DOI：
10.1063/1.4933425
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发表时间：
2015-10
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影响因子：
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通讯作者：
Wenkang Tu;Zeming Chen;Xiangqian Li;Yanqin Gao;Riping Liu;Li-Min Wang
中科院分区：
文献类型：
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作者：
Wenkang Tu;Zeming Chen;Xiangqian Li;Yanqin Gao;Riping Liu;Li-Min Wang
本文研究了苯与五种玻璃形成液体的二元混合物中苯的玻璃化转变和动力学，这五种玻璃形成液体可分为三组：（a）邻三联苯和间二甲苯，（B）甲基丙烯酸正丁酯，（c）N，N-二甲基丙酰胺和N，N-二乙基甲酰胺，分别代表与苯的弱、中等和强相互作用。测量了苯混合物的混合指数ΔH（mix），用它检验了玻璃化转变温度T（g）外推到富苯区的有效性。外推的T（g）的数据在混合物中被发现收敛在142 K附近的点，产生纯苯的T（g）。苯的脆性m也通过外推混合物的结果来评估，并且得到脆性m为80。得到的T（g）和m值苯允许在深度过冷区域的激活图的建设。苯的玻璃化成形性差是由于苯的熔点高，这反过来又导致过冷液体的粘度低。
The glass transition and dynamics of benzene are studied in binary mixtures of benzene with five glass forming liquids, which can be divided into three groups: (a) o-terphenyl and m-xylene, (b) N-butyl methacrylate, and (c) N,N-dimethylpropionamide and N,N-diethylformamide to represent the weak, moderate, and strong interactions with benzene. The enthalpies of mixing, ΔH(mix), for the benzene mixtures are measured to show positive or negative signs, with which the validity of the extrapolations of the glass transition temperature T(g) to the benzene-rich regions is examined. The extrapolations for the T(g) data in the mixtures are found to converge around the point of 142 K, producing T(g) of pure benzene. The fragility m of benzene is also evaluated by extrapolating the results of the mixtures, and a fragility m ∼ 80 is yielded. The obtained T(g) and m values for benzene allow for the construction of the activation plot in the deeply supercooled region. The poor glass formability of benzene is found to result from the high melting point, which in turn leads to low viscosity in the supercooled liquid.