POLYMERIZATION OF CYCLIC MONOMERS .3. SYNTHESIS, RADICAL AND CATIONICPOLYMERIZATION OF BICYCLIC 2-METHYLENE-1,3-DIOXEPANES

New bicyclic 2-methylene-1,3-dioxepanes, were synthesized starting fro m 2-bromomethyl-5,6-dihydroxy-1,3-dioxepanes. The structure of the 2-m ethylene-1,3-dioxepanes was confirmed by elemental analysis, IR, H-1 N MR and C-13 NMR spectroscopy. Radical polymerization of 2-methylene-1, 3-dioxepanes in bulk with 2,2'-azoisobutyronitrile (AIBN) and di-tert- butyl peroxide (DtBPO), respectively, gives highly viscous polymers. T he polymerization of liquid monomers is accompanied by negative volume changes. The spectroscopic investigations of the formed polymers show that 2-methylene-1,3-dioxepanes undergo primarily radical ring-openin g polymerization, whereas the cationic photopolymerization is mainly a vinyl polymerization.