Reaction behavior and network development in RAFT radical polymerization of dimethacrylates

The reaction behavior and development of network microstructure in the RAFT polymerization of OEGDMA were investigated. The polymerization rate of the RAFT system was much lower than in conventional FRP, largely due to the low propagating-radical concentration determined by the addition-fragmentation equilibrium. A mild auto acceleration occurred as the addition reaction became diffusion-controlled. The slow chain growth in the RAFT allowed sufficient chain relaxation and a uniform distribution of reacting species. The RAFT polymerization of OEGDMA with longer spacers yielded more homogeneous networks with a lower crosslinking density and lower Mass transition temperature than the FRP.