A study of the cationic copolymerization of ethyl and isopropyl vinyl ethers induced by radiation

The radiation -induced cationic copolymerization of ethyl and isopropyl vinyl ethers has been studied in bulk with varying compositions of the monomer feed. The copolymer compositions have been determined. The results show that incorporation rates of IPVE and EVE differ only by about 5 times, leading us to conclude that the large difference previously observed in the bulk homopolymerization rates comes mainly from the relative reactivity of the growing ends. The overall rate of consumption of the comonomers varies drastically with the composition of the feed and a deactivating effect of EVE on the homoaddition rate of IPVE has been observed. This was attributed to an intrasolvation of the growing IPVE+ ends by the last EVE units incorporated in the copolymer chain. (author)