Kabbej Marouane, Guillard Valérie, Angellier-Coussy Hélène, Wolf Caroline, Gontard Nathalie, Gaucel Sébastien
IATE, Univ Montpellier, CIRAD, INRAE, Institut Agro, 34060 Montpellier, France.
Polymers (Basel). 2021 Jul 9;13(14):2257. doi: 10.3390/polym13142257.
A three-dimensional model structure that allows considering interphase layer around permeable inclusions is developed to predict water vapor permeability in composite materials made of a matrix Poly(3-HydroxyButyrate--3-HydroxyValerate) (PHBV) including Wheat Straw Fiber (WSF) particles. About 500 two-phase structures corresponding to composites of different particles volume fractions (5.14-11.4-19.52 % v/v) generated using experimental particles' size distribution have permitted to capture all the variability of the experimental material. These structures have served as a basis to create three-phase structures including interphase zone of altered polymer property surrounding each particle. Finite Element Method (FEM) applied on these structures has permitted to calculate the relative permeability (ratio between composite and neat matrix permeability P/Pm). The numerical results of the two-phase model are consistent with the experimental data for volume fraction lower than 11.4 %v/v but the large upturn of the experimental relative permeability for highest volume fraction is not well represented by the two-phase model. Among hypothesis made to explain model's deviation, the presence of an interphase with its own transfer properties is numerically tested: numerical exploration made with the three-phase model proves that an interphase of 5 µm thick, with diffusivity of Di≥1×10-10 m2·s-1, would explain the large upturn of permeability at high volume fraction.
为预测由基质聚（3-羟基丁酸酯-3-羟基戊酸酯）（PHBV）制成并包含麦秸纤维（WSF）颗粒的复合材料中的水蒸气渗透率，开发了一种允许考虑围绕可渗透夹杂物的界面层的三维模型结构。利用实验颗粒尺寸分布生成的约500种对应于不同颗粒体积分数（5.14 - 11.4 - 19.52% v/v）复合材料的两相结构，能够捕捉实验材料的所有变异性。这些结构作为创建三相结构的基础，三相结构包括围绕每个颗粒的聚合物性质改变的界面区。应用于这些结构的有限元方法（FEM）已能够计算相对渗透率（复合材料与纯基质渗透率之比P/Pm）。两相模型的数值结果与体积分数低于11.4% v/v的实验数据一致，但两相模型不能很好地表示最高体积分数下实验相对渗透率的大幅上升。在为解释模型偏差所做的假设中，对具有自身传输特性的界面的存在进行了数值测试：用三相模型进行的数值探索证明，厚度为5 µm、扩散率Di≥1×10 - 10 m2·s - 1的界面可以解释高体积分数下渗透率的大幅上升。
