Synthesis and Characterization of a Novel Macromonomer Initiator for Reversible Addition Fragmentation Chain Transfer (RAFT). Evaluation of the Polymerization Kinetics and Gelation Behaviors

Abstract

Reversible addition fragmentation chain transfer, RAFT, self condensing a novel macromonomer initiator polymerization and copolymerization with methyl methacrylate, MMA, in the presence of 2,2′ -azobisisobutyronitrile, AIBN, has been reported. RAFT-MIM was obtained from potassium salt of the ethyl xanthegonate and the terminally brominated poly (ethylene glycol) methacrylate (v-PEG-Br) which was synthesized by the reaction of poly (ethylene glycol) methacrylate, v-PEG-OH with M_n = 526 Dalton and 3-bromopropionyl chloride. Self condensing RAFT-MIM polymerization and copolymerization with MMA gave highly branched and cross-linked amphiphilic copolymers. The kinetic parameters were evaluated by changing some polymerization conditions such as monomer, initiator and solvent concentration, polymerization time and polymerization temperature. The plots of ln (M₀/M) versus reaction time are linear, corresponding to first-order kinetics. The overall polymerization rate constant, k, was calculated as 7.9 × 10⁻⁵ s⁻¹. The products were characterized by ¹H-NMR and TGA. Swelling ratio values of the crosslinked products in CHCl₃ were also determined.

Keywords:

• Reversible addition fragmentation chain transfer
• macromonomeric initiator
• self condensing polymerization
• swelling ratio

Acknowledgements

This work was supported by the Scientific Research Projects Commission (ZKU-BAP) of Zonguldak Karaelmas University (Grants#2008-13-02-03 and 2008-70-01-01) and TUBITAK (Grant#108T423 and 108T981). The authors are also thankful to Kafkas University (Kars, Turkey) for supporting one of us (T.Ö.).