ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 22, Number 3
JKCSEZ 22(3)
June 20, 1978 

Bulk polymerization of propylene sulfide with o-sulfobenzoic anhydride as initiator was carried out and the polymerization proceeded by a zwitterionic mechanism. Chemical and spectroscopic investigation of the purified polymer revealed that the polymer contained two end groups-thiolester of benzoic acid o-sulfonate anions and acyclic tert-sulfonium ions which were formed by termination of episulfonium ions with sulfide groups in the polymer chains. The concentration of sulfonate anions was nearly the same as the concentration of acyclic tert-sulfonium ions, as expected for macrozwitterions. The cocatalysis mechanism by a trace of water was excluded and the other possible mechanisms were discussed on the basis of end group analysis.