Drying process paths of ternary polymer solution coating
Drying process paths of ternary polymer solution coating
复制标题
三元聚合物溶液涂料的干燥工艺路线
DOI：
10.1002/aic.690480105
复制
发表时间：
2002
期刊：
影响因子：
3.7
通讯作者：
L. Scriven
中科院分区：
文献类型：
--
作者：
Mahendra Dabral;L. Francis;L. Scriven
分析了由溶解在溶剂和非溶剂的共混物中的聚合物组成的三元溶液的干燥过程路径。应用于三元溶液的1-D干燥模型提供了随时间变化的涂层中不同深度处的组合物轨迹，统称为工艺路径。气相传质系数，相对扩散系数和相对挥发度，以及部分饱和的气相溶剂对这些过程路径的影响。当溶液涂层进入两相区时，可能发生相分离，如由醋酸纤维素在酮和甲醇中的三元溶液制备的涂层所示。当丙酮是溶剂时，涂层相分离。用甲乙酮代替丙酮得到均匀的涂层。溶液相分离或“脸红”的干燥过程的路径和它们的关系，两相不混溶区域的条款解释。
Drying process paths of a ternary solution consisting of a polymer dissolved in a blend of a solvent and a nonsolvent are analyzed. A 1-D drying model applied to a ternary solution provides composition trajectories followed at different depths in the coating as a function of time, collectively called process paths. The effects of gas-phase mass-transfer coefficient, relative diffusivity and relative volatility, and partial saturation of the gas phase with solvents on these process paths are presented. When the solution coating enters the two-phase region, phase separation may take place, as illustrated by coatings prepared from ternary solutions of cellulose acetate in ketone and methanol. When acetone is the solvent, the coating phase separates. Replacing acetone with methyl ethyl ketone gives homogeneous coatings. Solution phase separation or “blush” is explained in terms of the drying-process paths and their relationship to the two-phase immiscible region.