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The glass transition of amorphous polymers: About a continuous equation of state and its derivatives
Journal of Applied Polymer Science ( IF 2.7 ) Pub Date : 2021-03-22 , DOI: 10.1002/app.50662
Claudio Corbisieri 1 , Pierre Jousset 1 , Markus Roos 2
Affiliation  

Describing the pressure‐volume‐temperature (PVT) behavior of polymers is often hindered due to limitations of models and theories. In this work, we propose the logistic function to derive a phenomenological equation of state (EOS) that overcomes these limitations. Without dividing the temperature domain into several intervals, this continuous EOS describes the PVT behavior of amorphous polymers in the equilibrium state, the vitreous state and at glass transition. Discontinuities at glass transition are inherently eliminated. The EOS is continuously differentiable with respect to temperature and pressure. The thermal expansion coefficient and compression modulus thus can be determined at any valid reference state. The EOS linearly depends on temperature both in the equilibrium state and vitreous state. Furthermore, a parameter of the EOS is interpreted as the pressure‐dependent glass transition temperature. Using PVT data of polyethersulfone (PES), measured in the temperature range of 20 − 360 °C and pressure range of 10 − 200 MPa in both the isobaric and standard isothermal mode, the validity of the EOS is discussed. Polymer processing simulation and solid mechanics benefit from the EOS and its derivatives, respectively. In addition, the EOS can be used to determine the glass transition temperature from PVT data.

中文翻译:

非晶态聚合物的玻璃化转变:关于状态及其衍生物的连续方程

由于模型和理论的局限,通常难以描述聚合物的压力-体积-温度(PVT)行为。在这项工作中,我们提出了逻辑函数,以导出克服这些局限性的现象学状态方程(EOS)。在不将温度域划分为几个区间的情况下,这种连续的EOS描述了处于平衡态,玻璃态和玻璃化转变状态的非晶态聚合物的PVT行为。本质上消除了玻璃化转变时的不连续性。EOS在温度和压力方面可以连续区分。因此,可以在任何有效的参考状态下确定热膨胀系数和压缩模量。EOS在平衡状态和玻璃状态下都线性依赖于温度。此外,EOS的参数被解释为取决于压力的玻璃化转变温度。使用聚醚砜(PES)的PVT数据,在温度范围内测得在等压模式和标准等温模式下,温度为20 − 360°C,压力范围为10 − 200 MPa,讨论了EOS的有效性。聚合物加工模拟和固体力学分别受益于EOS及其衍生物。此外,EOS可用于根据PVT数据确定玻璃化转变温度。
更新日期:2021-04-11
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