Synthesis of novel telechelic polymeric photoinitiators by ultrafast/fast raft polymerization using a highly active photofunctional raft agent and preparation of aba-type block copolymers from them by photopolymerization

This thesis consists of three main stages: i) design and synthesis of a RAFT agent with multiple functionalities and high activity, ii) preparation of block copolymers from monomers polymerized by different mechanisms using this agent, iii) investigation of parameters such as RAFT polymerization rate, efficiency and dynamics. In the first stage of the study, a special photofunctional RAFT agent that can both control RAFT polymerization and initiate photopolymerization was designed and synthesized. This high activity agent, which allows RAFT polymerization at very high speeds, was obtained by introducing photoactive benzoin molecules to the carboxyl groups at both ends of the trithiocarbonate-based bis(dimethylacetic acid) precursor compound. In the second stage, the newly developed RAFT agent was successfully used as a chain transfer agent (CTA) in the RAFT polymerization of acrylonitrile (AN), acrylamide (AM), styrene (St) and methyl methacrylate (MMA) monomers, and four different telechelic polymeric photoinitiators were synthesized. During these polymerizations, above-average rates were observed for St and MMA monomers, while AN and AM polymerizations were completed at an extraordinary speed (ultrafast) (<5 min). These polymeric photoinitiators were used as prepolymers, and eight ABA type block copolymers were obtained by photoinitiated free radical-promoted cationic polymerization (FRPCP) of cyclohexene oxide (CHO) and butyl vinyl ether (BVE) monomers. In the third stage, polymerization rate, efficiency and dynamics of the RAFT polymerization of styrene, which occurs relatively slower, were investigated by time-dependent 1H NMR analysis. The findings showed that CTA initially initiated a polymerization at an ultrafast rate, but the dormant species formed slowed down the process significantly. All molecules and the resulting polymers were extensively characterized using techniques such as FT-IR, 1H-NMR, 13C-NMR, GPC, UV-vis, fluorescence and elemental analysis.