Tabernero Antonio, Baldino Lucia, Cardea Stefano, Martín Del Valle Eva, Reverchon Ernesto
Department of Chemical Engineering, University of Salamanca, Plaza los Caídos s/n, 37008 Salamanca (SA), Spain.
Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano (SA), Italy.
Polymers (Basel). 2019 Mar 13;11(3):485. doi: 10.3390/polym11030485.
This work proposes a modeling of the mechanical properties of porous polymers processed by scCO₂, using a phenomenological approach. Tensile and compression tests of alginate/gelatin and cellulose acetate/graphene oxide were modeled using three hyperelastic equations, derived from strain energy functions. The proposed hyperelastic equations provide a fair good fit for mechanical behavior of the nanofibrous system alginate/gelatin (deviations lower than 10%); whereas, due to the presence of the solid in the polymer network, a four-parameter model must be used to fit the composite cellulose acetate/graphene oxide behavior. Larger deviations from the experimental data were observed for the system cellulose acetate/graphene oxide because of its microporous structure. A finite element method was, then, proposed to model both systems; it allowed a realistic description of observable displacements and effective stresses. The results indicate that materials processed using scCO₂, when submitted to large stresses, do not obey Hooke´s law and must be considered as hyperelastic.
本研究采用唯象学方法，对超临界二氧化碳（scCO₂）处理的多孔聚合物的力学性能进行建模。利用从应变能函数导出的三个超弹性方程，对藻酸盐/明胶和醋酸纤维素/氧化石墨烯进行拉伸和压缩试验建模。所提出的超弹性方程能较好地拟合纳米纤维体系藻酸盐/明胶的力学行为（偏差低于10%）；然而，由于聚合物网络中存在固体，必须使用四参数模型来拟合复合醋酸纤维素/氧化石墨烯的行为。由于醋酸纤维素/氧化石墨烯体系的微孔结构，观察到其与实验数据的偏差较大。然后，提出了一种有限元方法对这两个体系进行建模；它能够真实地描述可观察到的位移和有效应力。结果表明，使用scCO₂处理的材料在承受大应力时，不服从胡克定律，必须视为超弹性材料。
