Baldanza Antonio, Loianno Valerio, Mensitieri Giuseppe, Scherillo Giuseppe
Department of Chemical, Materials and Production Engineering, University of Naples Federico II, P.le Tecchio 80, Naples 80125, Italy.
Philos Trans A Math Phys Eng Sci. 2023 Jan 9;381(2240):20210216. doi: 10.1098/rsta.2021.0216. Epub 2022 Nov 21.
Polymer matrices, when placed in contact with a fluid phase made of low molecular weight compounds, undergo a depression of their glass transition temperature () determined by the absorption of these compounds and the associated plasticization phenomena. Frequently, this effect is coupled with the mechanical action of the compressive stress exerted by the pressure of the fluid phase that, in contrast, promotes an increase in the . This issue is relevant for technological and structural applications of composites with high-performance glassy polymer matrices, due to their significant impact on mechanical properties. We propose an approach to model and predict rubbery-glassy states maps of polymer-penetrant mixtures as a function of pressure and temperature based on the Gibbs-Di Marzio criterion. This criterion establishes that a 'thermodynamic' glass transition does occur when the configurational entropy of the system vanishes. Although questioned and criticized, this criterion constitutes a good practical approach to analyse changes of and, in some way, reflects the idea of an 'entropy catastrophe' occurring at the glass transition. Several polymer-penetrant systems have been analysed modelling configurational entropy by means of the Non-Random Hydrogen Bond lattice fluid theory, able to cope with possible non-random mixing and occurrence of strong interactions. This article is part of the theme issue 'Ageing and durability of composite materials'.
当聚合物基体与由低分子量化合物构成的流体相接触时，其玻璃化转变温度（）会因这些化合物的吸收及相关增塑现象而降低。通常，这种效应会与流体相压力施加的压缩应力的机械作用相结合，而压缩应力相反会促使升高。由于其对机械性能有重大影响，这个问题对于具有高性能玻璃态聚合物基体的复合材料的技术和结构应用而言至关重要。我们基于吉布斯 - 迪马尔齐奥准则提出一种方法，用于模拟和预测聚合物 - 渗透剂混合物的橡胶态 - 玻璃态状态图随压力和温度的变化。该准则表明，当系统的构型熵消失时，确实会发生“热力学”玻璃化转变。尽管受到质疑和批评，但该准则构成了分析变化的良好实用方法，并且在某种程度上反映了玻璃化转变时发生“熵灾变”的观点。借助非随机氢键晶格流体理论对构型熵进行建模，已经分析了几种聚合物 - 渗透剂体系，该理论能够应对可能的非随机混合以及强相互作用的出现。本文是主题为“复合材料的老化与耐久性”的一部分内容。
