Dielectric relaxation and calorimetric measurements of glass transition in the glass-forming dyhydroxyl alcohols
Dielectric relaxation and calorimetric measurements of glass transition in the glass-forming dyhydroxyl alcohols
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玻璃形成二元醇中玻璃化转变的介电弛豫和量热测量
DOI：
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
S. Kojima
中科院分区：
文献类型：
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作者：
I. Park;K. Saruta;S. Kojima
为了研究中间玻璃形成材料的α-弛豫和玻璃化转变的分子量依赖性，对液态和过冷液态下的介电和热性能进行了研究。通过10 mHz调制DSC和10 mHz至10 GHz频率范围内的宽带介电谱，研究了化学结构相似但分子量不同（76-4000 g/mol）的丙二醇（PG）及其五种低聚物（聚丙二醇，PPG），关注它们的脆性和协同性。使用分子间协同模型和 Adam-Gibbs 模型对介电和热测量中的 PG 和 PPG 的脆性进行了分析和比较。使用比较方法评估了 PG 和 PPG 的 Vogel-Fulcher 能量和最小构型熵。它们的值与-OH端基的密度及其分子间氢键有关。强度参数下降...
In order to study the molecular weight dependence of the α-relaxation and glass transitions of intermediate glass-forming materials, the dielectric and thermal properties have been investigated in both liquid and supercooled liquid states. By means of modulated DSC at 10 mHz and broadband dielectric spectroscopy in the frequency range from 10 mHz to 10 GHz, propylene glycol (PG) and its five oligomers (poly propylene glycol, PPG), which have the similar chemical structure but different molecular weights 76–4000 g/mol, were studied paying attention to their fragility and cooperativity. The fragility of PG and PPGs from the dielectric and thermal measurements was analyzed and compared using both the intermolecular cooperativity model and the Adam-Gibbs model. The Vogel-Fulcher energy and minimum configurational entropy were evaluated for PG and PPGs using the comparison method. Their values were related to the density of -OH end group and its intermolecular hydrogen bonding. The strength parameter decreased...