CTS-0107168 S. K. Mallapragada, Iowa State University
This proposal represents a tri-national collaborative effort between the principal investigator Dr. Surya Mallapragada at Iowa State University (USA), Dr. Sacide Alsoy at Izmir Institute of Technology (Turkey) and Dr. Joseph Miltz at Technion (Israel), devoted to investigating the multicomponent drying mechanism of semicrystalline polymer packaging materials. This collaborative effort was initiated during the US-Israel-Turkey tripartite workshop sponsored 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 and their effect on the drying kinetics. Use these to investigate the drying mechanism of CA films and validate the model. 3. Investigate the influence of drying conditions of CA films on their characteristics as packaging materials. Evaluate the permeability of the films to gases and their mechanical properties 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.
