Micellar polymerization behavior of alpha,omega-divinylbenzyl poly (ethylene oxide) macromonomers

The properties of aggregates formed by associating polymers in aqueous solu tion have attracted widespread interest. Such polymers are used as rheology control agents in water-based surface coatings. Telechelic poly(ethylene o xide) (PEO) associating polymers, which have hydrophobic groups at both end s, form the "flower type" aggregates at low concentration. When the concent ration exceeds the critical overlapping concentration of the "flowers", the connectivity through the PEO chains takes place progressively to form the micelles connected by "superbridges" or associated with "superloops" or "da ngling ends". In the present study, amphiphilic telechelic macromonomers (V B-PEO-VB-n, n=21, 41, 67) with vinylbenzyl groups (VB) in both ends of a PE O chain were synthesized, and their micellar homopolymerization behavior wa s studied. It was found that in water VB-PEO-VB-n polymerizes very rapidly as a results of micelle organization to afford the flower-type branched pol ymers with high degrees of polymerization. However, the polymerization syst em produced the phase separation and gelation when increasing macromonomer concentration and temperature. The aggregation behavior of the telechelic m acromonomers was investigated and is discussed along with the polymerizatio n behavior.