Tandem isomerization and cationic polymerization of allyl ethers and novel hybrid monomers bearing cycloaliphatic epoxy and 1-propenyl ether functionalities

Two investigations in cationic polymerization were conducted. The first investigation was focused towards the development of novel catalyst systems for the tandem isomerization and cationic polymerization of allyl ethers and other analogous compounds. The second investigation was aimed towards the synthesis, photoinitiated cationic polymerization and structure-reactivity relationships of novel hybrid monomers.; Allyl ethers are a easily prepared and inexpensive class of compounds, which heretofore have efficient resisted polymerization by any known means. In the presence of catalytic amounts of dicobalt octacarbonyl. (Co2(CO) 8) and a hydrido silane (R3SiH), efficient rapid and exothermic polymerization of allyl ethers ensued resulting in well-characterized, high polymers. Detailed mechanistic studies conducted support a stepwise process, involving first, the reaction of dicobalt octacarbonyl with an organosilane to form HCo(CO)4 and R3SiCo(CO)4. In subsequent steps, HCo(CO)4 isomerizes the allyl ether to a 1-propenyl ether and then this compound is polymerized by the formal transfer of a silyl cation from R3SiCo(CO)4. This new polymerization reaction is fairly general in nature and the polymerization occurs in allyl ethers with a variety of structures and functional groups. Other Group VIII transition metal carbonyl compounds were also found to be active catalysts, while metal carbonyl complexes of other transition metals were inactive. Copolymerization studies have indicated statistical nature and showed that the isomerization of individual monomers and their subsequent copolymerization proceeded at very nearly identical rates.; The synthesis of a series of novel hybrid monomers that contain both a cycloaliphatic epoxide and 1-propenyl ether on the same molecule was achieved using a simple three step methodology. The rate of polymerization was monitored by real-time infrared spectroscopy under photoinitiated cationic polymerization conditions. These new "hybrid" monomers exhibited unprecedented reactivity for the epoxide ring-opening under cationic photopolymerization conditions. Mechanistic and model compound studies showed that a radical-assisted decomposition of the iodonium salt photoinitiator was responsible for the acceleration of the rate of cationic polymerization.