[1] Laboratory of Plastics and Rubber Technology, Department of Materials Science, Budapest University of Technology and Economics, P.O. Box 91, H-1521 Budapest, Hungary
[2] Institute of Materials and Environmental Chemistry, Chemical Research Center, Hungarian Academy of Sciences, P.O. Box 17, H-1525 Budapest, Hungary
[3] Institute of Structural Chemistry, Chemical Research Center, Hungarian Academy of Sciences, P.O. Box 17, H-1525 Budapest, Hungary