POLYMERIZATION INSIDE THE MOLECULAR-SIEVES

Attempts have been made to use the molecular sieves as a matrix for intracrystalline polymerization. Although the polycondensation of resols is significantly affected by the presence of certain molecular sieves, the latter do not facilitate the polymerization of styrene. Styrene, however, reacts with zeolites H-ZSM-5, H-mordenite and also with silicalite-l and AlPO4-11 modified with fluorine to form the colored species that cannot be removed from the molecular sieves. ESR measurement indicates a radical nature of these species. The protonic acid sites and specific geometry of the channels (0.5 - 0.7nm) seem to be indispensable for their generation. Strong chemical interaction between styrene and the molecular sieves decreases the rate of styrene polymerization.