INVESTIGATION OF THE MECHANISM OF CROSSOVER REACTION OF P-DICUMYL CHLORIDE BCL3/ISOBUTYLENE SYSTEM BY GLASS-FIBER OPTIC PHOTOMETRY/

A thorough kinetic investigation was done by measuring the optical den sity of reaction mixtures of the pDCC/BCl3 initiating system in the pr esence and in the absence of monomer and added salt at 500 nm and at - 80 degrees C. The absolute rate constants of elementary steps of the i on generation and cationation were evaluated by computer using a fitti ng method for determination of the parameters occurring in the kinetic model. The key activated species of the mechanism are identified to b e colorless donor-acceptor complexes. The color of reaction mixtures i s caused by ionized species. On the basis of the calculations and othe r evidences, a well-established mechanism is proposed. Both -C-t-Cl an d -C-t-OH endgroups were found by MS/EI. GPC analysis of the reaction products indicates that the major product is dimer under the reaction conditions applied.