1. 1Department of Natural and Synthetic Polymers, Faculty of Chemical Engineering, “Gh. Asachi” Technical University of Iasi, D. Mangeron St., 71A, 700050, Iasi, Romania; tel/fax: +40-232-271311
2. 2Ecole des Mines de Douai, Polymers and Composites Technology & Mechanical Engineering Department, 941 Rue Charles Bourseul, F-59508 Douai, France