Polymerization of 1,3-Dienes with Functional Groups. 5. RAFT Polymerization of N,N-diethyl-2-methylene-3-butenamide

Reversible addition-fragmentation chain transfer (RAFT) polymerization of N,N-diethyl-2-methylene-3-butenamide (DEA), which is a 1,3-butadiene derivative containing a diethylamide function, was carried out in chlorobenzene with using benzyl dithiobenzoate (BDB) as a chain transfer agent. When DEA was polymerized at 70°C using azobisisobutyronitrile (AIBN) as an initiator in the presence of BDB, polymers of narrow molecular weight distribution (Mw/Mn<1.2) were obtained. The molecular weight increased proportionally with conversion, and the observed values were close to the calculated ones based on the molar ratio of monomer to BDB. This indicates that the molecular weight of the polymer can be controlled by the molar ratio of monomer to chain transfer agent. PolyDEA thus obtained contained BDB fragment which was confirmed by MALDI-TOF-MS analysis. Block copolymerization with styrene was carried out using polyDEA having BDB fragment as macro chain transfer agent. Microstructure of polyDEA was predominantly 1,4-sructure. Thus simultaneous control of the molecular weight and microstructure was achieved in the RAFT polymerization of DEA.