Multicomponent Drying of Semicrystalline Polymer Films

摘要CTS-0107168S。爱荷华州立大学K·马拉普拉加德这项提案是艾奥瓦州立大学(美国)的首席研究员Surya Mallapradada博士、伊兹密尔理工学院的Sacide Alsoy博士(土耳其)和Technion的Joseph Miltz博士(以色列)三国合作的成果，致力于研究半结晶聚合物包装材料的多组分干燥机理。这一合作努力是在1999年3月在以色列海法举行的由美国国家科学基金会赞助的美国-以色列-土耳其三方研讨会期间发起的。在包装材料、胶带、照相胶片和各种功能涂料等大量产品的生产中，溶剂去除是一个关键的加工步骤，其中许多产品是由半结晶聚合物制成的。该合作项目的目的是研究多组分溶剂的去除机理以及半结晶聚合物在干燥过程中结晶度和微观结构的变化。这反过来又对聚合物用于各种应用(如包装)的最终性能有很大影响。其中使用的重要包装材料之一是醋酸纤维素(CA)，它将成为模型体系。在食品包装应用中，我们将采用实验研究和数学建模双管齐下的方法来处理半结晶聚合物的多组分干燥问题，以优化干燥条件和干燥机设计。具体的研究目标是：1.建立半结晶聚合物膜中溶剂去除的多组分模型。实验研究了CA膜的溶剂诱导结晶动力学及其对干燥动力学的影响。研究了CA膜的干燥机理，验证了模型的正确性。考察了干燥条件对CA膜包装材料特性的影响。评估薄膜对气体的透过性及其机械性能作为干燥条件的函数。这项工作也是第一个用来预测半结晶聚合物非等温多组分干燥动力学的模型。通过选取合适的参数值，该模型可适用于任何聚合物-溶剂体系。这项工作中提出的分子理解和基于应用的实验之间的协同作用将使工业干燥过程的准确预测成为可能。

AbstractCTS-0107168S. K. Mallapragada, Iowa State UniversityThis proposal represents a tri-national collaborative effort between the principalinvestigator Dr. Surya Mallapragada at Iowa State University (USA), Dr. Sacide Alsoy atIzmir Institute of Technology (Turkey) and Dr. Joseph Miltz at Technion (Israel), devoted toinvestigating the multicomponent drying mechanism of semicrystalline polymer packagingmaterials. This collaborative effort was initiated during the US-Israel-Turkey tripartite workshopsponsored by the National Science Foundation and held in Haifa, Israel in March 1999. Solvent removal is a key processing step in the production of a plethora of products such as packaging materials, adhesive tapes, photographic films and various functional coatings, many of which are made from semicrystalline polymers. The aim of this collaborative project is to investigate the mechanism of multicomponent solvent removal and the changes in the degree of crystallinity and the microstructure of semicrystalline polymers during drying. This, in turn, has a strong effect on the final properties of the polymer for various applications such as packaging. One of the important packaging materials used is cellulose acetate (CA) which will be the model system. A two pronged approach involving experimental investigations and mathematical modeling will be used to deal with the problem of multicomponent drying of semicrystalline polymers in the context of food packaging applications to enable optimization of drying conditions and dryer designs. The specific research objectives are to: 1. Develop a multicomponent model for solvent removal from semicrystalline polymer films.2. Experimentally investigate the solvent induced crystallization kinetics of CA films andtheir effect on the drying kinetics. Use these to investigate the drying mechanism of CA filmsand validate the model.3. Investigate the influence of drying conditions of CA films on their characteristics aspackaging materials. Evaluate the permeability of the films to gases and their mechanicalproperties as a function of drying conditions. This work also represents the first model developed to predict non-isothermal multi-component drying kinetics of semicrystalline polymers. The model will be applicable to any polymer-solvent system by using suitable parameter values. The synergy between molecular understanding and application-based experimentation proposed in this work will enable accurate predictions of industrial drying processes.