Cationic Polymerization by Perchloric Acid and Related Initiators

摘要

The report gives general descriptions and quantitative results of polymerization of styrene and of two related monomers, initiated by perchloric acid, and by carbonium salt initiators. The styrene-perchloric acid polymerization, studied between 25 and -97C, proved particularly informative, and can now be given a very detailed interpretation in terms of a true cationic (not pseudo cationic) propagating species which can undergo alternating terminations and revivals. The molecular weights, which superficially show great complexity of behaviour can be fully accounted for. They are controlled by the termination process and by a process of 'spontaneous' transfer (rejection of the initiator molecule). Above -30 transfer to monomer is of growing importance. Studies with different carbonium-ion salts indicate that higher molecular weights may be obtained by diminution of the spontaneous transfer process when the catalyst anion is less basic. (Author)