| Abstract: | A spectroscopic method is described for the determination of the concentration of propagating species, P*], in the polymerization of tetrahydrofuran catalyzed by a mixture of AlEt3?H2O (1:0.5) and epichlorohydrin. A phenyl ether group was introduced at the polymer chain end by the quantitative reaction of the propagating species with excess sodium phenoxide. From the amount of phenyl ether groups in the polymer and of the remaining sodium phenoxide, P*] was determined by means of ultraviolet spectroscopy. The P*] value so determined was found to be in good agreement with that calculated from the amount and molecular weight of polymer based on a stepwise addition mechanism without chain transfer or termination. The present method of P*] determination was employed to examine the course of polymerization. It has now been found that P*] increases progressively during an induction period and remains unchanged in the subsequent period of polymerization. |
