Thoury-Monbrun Valentin, Angellier-Coussy Hélène, Guillard Valérie, Legland David, Gaucel Sébastien
JRU IATE 1208-CIRAD/INRA/Montpellier Supagro/University of Montpellier, 2 Place Pierre Viala, Bat 31, F-34060 Montpellier, France.
INRA, Biopolymères Interactions Assemblages (BIA), Rue de la Geraudière, F-44000 Nantes, France.
Materials (Basel). 2018 Sep 13;11(9):1712. doi: 10.3390/ma11091712.
This work aims at assessing the impact of two-dimensional particle size distribution (2D-PSD) on the identification of water vapor diffusivity in micrometric size cellulose particles displaying a size aspect ratio lower than 2 and a cylindrical shape. First, different methodologies to obtain the two-dimensional (2D) particle size distribution (diameter versus length) were compared, based on image analysis. Then, experimental sorption kinetics were obtained by using a quartz crystal microbalance (QCM) coupled with a water vapor adsorption system. Diffusivity values were estimated when considering either the 2D-PSD or global descriptors, such as the mean or median diameter and length of particles. Results revealed that the use of an analytical approach when considering the 2D mean-PSD or the median-PSD was the most accurate way to get diffusivity values at the scale of particles in a polydisperse sample of cellulose particles. Following this approach, a water vapor apparent diffusivity of 3.1 × 10 ± 2.3 × 10 m²·s was found for the considered cellulose sample. Neglecting PSD in diffusivity estimation led to an underestimation of a factor of 2. This procedure could be extended for all the polydisperse samples in order to have an accurate estimation of water vapor diffusivity at the scale of single particles.
这项工作旨在评估二维粒度分布（2D-PSD）对识别尺寸长宽比小于2且呈圆柱形的微米级纤维素颗粒中水蒸气扩散率的影响。首先，基于图像分析，比较了获得二维（2D）粒度分布（直径与长度）的不同方法。然后，通过使用与水蒸气吸附系统耦合的石英晶体微天平（QCM）获得实验吸附动力学。在考虑2D-PSD或全局描述符（例如颗粒的平均或中值直径和长度）时估计扩散率值。结果表明，在考虑2D平均PSD或中值PSD时使用分析方法是在多分散纤维素颗粒样品中获得颗粒尺度扩散率值的最准确方法。按照这种方法，对于所考虑的纤维素样品，发现水蒸气表观扩散率为3.1×10±2.3×10 m²·s。在扩散率估计中忽略PSD会导致低估2倍。该程序可以扩展到所有多分散样品，以便在单个颗粒尺度上准确估计水蒸气扩散率。
