1. A.V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, 29, Leninsky Pr., 119991, Moscow, Russia; N.N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, 4, Kosygina Ul., 117977, Moscow, Russia; Chemical Engineering Department, North Carolina State University, Raleigh, North Carolina 27695-7905; and Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, 606-01 Kyoto, Japan