1. Emulsion Polymers Institute, Lehigh University, Bethlehem, PA 18015
2. Current address: Polymer Products Department, E. I. du Pont de Nemours and Company, 4200 Campground Road, Louisville, KY 40216
3. Current address: General Electric Corporate Research and Development Center, Building K-1/CEB 126, P.O. Box 8, Schenectady, NY 12301
4. Department of Chemical Engineering, Lehigh University, Bethlehem, PA 18015