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Vibrational heat capacity of the linear 6,4-polyurethane
Thermochimica Acta ( IF 3.5 ) Pub Date : 2020-01-01 , DOI: 10.1016/j.tca.2019.178433
A. Czerniecka-Kubicka , W. Zielecki , W. Frącz , M. Janus-Kubiak , L. Kubisz , M. Pyda

Abstract The calculated vibrational heat capacity of the linear 6,4-polyurethane (6,4-PU) in the solid state was estimated using its vibrational motions. The experimental low-temperature heat capacity of 6,4-PU collected from literature was related to approximate vibrational spectra based on the group and skeletal vibration contributions of 6,4-PU using the Advanced Thermal Analysis System (ATHAS) Data Bank. The group vibrational heat capacity was calculated based on ninety molecular vibrational motions derived from Raman and infrared spectroscopy. The skeletal vibrational heat capacity was described by a general Tarasov equation with Debye temperatures of Θ1 = 452 K, and Θ2 = Θ3 = 96 K and thirty skeletal vibrations. The liquid heat capacity of semicrystalline polyurethane (6,4-PU) was approximated from experimental data using a linear regression of the data above the melting region and the heat capacity of the fully amorphous material above the glass transition temperature. The equilibrium liquid heat capacity was expressed as Cp(liquid) = 1.0041T+233.24 in. J·K-1· mol-1. The solid and liquid heat capacities of linear polyurethane (6,4-PU) were applied as equilibrium baselines for advanced thermal analysis of the experimental, apparent heat capacity data.

中文翻译:

线性 6,4-聚氨酯的振动热容

摘要 固态线性 6,4-聚氨酯 (6,4-PU) 的振动热容是通过振动运动来估计的。从文献中收集的 6,4-PU 的实验低温热容量与基于 6,4-PU 的组和骨架振动贡献的近似振动谱相关,使用高级热分析系统 (ATHAS) 数据库。基于来自拉曼和红外光谱的九十分子振动运动计算群振动热容量。骨架振动热容由一般的塔拉索夫方程描述,其中德拜温度为 Θ1 = 452 K,Θ2 = Θ3 = 96 K 和 30 次骨架振动。半结晶聚氨酯的液体热容 (6, 4-PU) 是使用高于熔化区的数据和高于玻璃化转变温度的完全无定形材料的热容量的线性回归从实验数据近似得出的。平衡液体热容量表示为 Cp(liquid) = 1.0041T+233.24 in. J·K-1·mol-1。线性聚氨酯 (6,4-PU) 的固体和液体热容被用作平衡基线,用于对实验表观热容数据进行高级热分析。
更新日期:2020-01-01
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