1. Faculty of Chemistry, Department of Fuels Chemistry and Technology, Wroclaw University of Technology, 7/9 Gdanska Street, Wroclaw 50-344, Poland, Rubber Research Institute “Stomil”, 30 Harcerska Street, Piastow 05-820, Poland, and Institute of Environment Protection Engineering, Wroclaw University of Technology, 9 Grunwaldzki Pl., 50-377 Wroclaw, Poland