Abstract: A series of poly(phenylene oxide) (PPO) resins with different low molecular weights were prepared by using the high-molecular-weight PPO, and their molecular weights were monitored by GPC during the synthetic process. Furthermore, the chain-growth mechanisms in the polymerization process were studied systematically. The investigation results indicated that the redistribution and rearrangement mechanisms did not always exist simultaneously in the process of chain growth. The process could be divided into the following three stages: redistribution chain growth, rearrangement and redistribution chain growths and dynamic equilibrium of redistribution. The molecular-weight control of the synthesized PPO could be reasonably explained by a combination of productivity and GPC characterization for the chain growth. This work opens up a new insight into the study of chain-growth mechanisms.

Key words: poly(phenylene oxide);chaingrowth mechanism, yield, molecular-weight control