JRU IATE 1208 - CIRAD, INRA, Montpellier Supagro, University of Montpellier, 2 Place Pierre Viala, Bat 31, F-34060 Montpellier 01, France.
IEM ENSCM, UM, CNRS UMR 5635, Université de Montpellier, 2 Place Eugène Bataillon, 34095 Montpellier cedex 05, France.
Carbohydr Polym. 2018 Jun 15;190:307-314. doi: 10.1016/j.carbpol.2018.02.068. Epub 2018 Feb 26.
This study aims at assessing the use of a quartz crystal microbalance (QCM) coupled with an adsorption system to measure water vapor transfer properties in micrometric size cellulose particles. This apparatus allows measuring successfully water vapor sorption kinetics at successive relative humidity (RH) steps on a dispersion of individual micrometric size cellulose particles (1 μg) with a total acquisition duration of the order of one hour. Apparent diffusivity and water uptake at equilibrium were estimated at each step of RH by considering two different particle geometries in mass transfer modeling, i.e. sphere or finite cylinder, based on the results obtained from image analysis. Water vapor diffusivity values varied from 2.4 × 10 m s to 4.2 × 10 m s over the tested RH range (0-80%) whatever the model used. A finite cylinder or spherical geometry could be used equally for diffusivity identification for a particle size aspect ratio lower than 2.
本研究旨在评估使用石英晶体微天平（QCM）与吸附系统测量微尺度纤维素颗粒中的水蒸气传递性质。该仪器可成功测量在单个微尺度纤维素颗粒（1μg）分散体上的水蒸气吸附动力学，在每个相对湿度（RH）步骤下，总采集时间约为一个小时。通过在质量传递建模中考虑两种不同的颗粒几何形状（球体或有限圆柱），基于图像分析结果，在每个 RH 步骤估算表观扩散系数和平衡吸水率。水蒸气扩散系数值在测试的 RH 范围（0-80%）内变化，从 2.4×10-9 m2 s-1 到 4.2×10-9 m2 s-1，无论使用哪种模型。对于粒径纵横比低于 2 的颗粒，有限圆柱或球形几何形状都可以同样用于扩散系数的识别。
