WELL-DEFINED GRAFT-COPOLYMERS VIA COUPLED LIVING ANIONIC AND LIVING RING-OPENING METATHESIS POLYMERIZATION

The synthesis of macromonomers via the reaction of living polystyrene capped with propylene oxide with bicyclo[2.2.1]hept-5-ene-2,3-trans-di carbonyl chloride and living ROMP of the macromonomers using well-defi ned Schrock molybdenum initiator to produce well-characterised graft c opolymers is described. The scaling up of the ROMP of the macromonomer s of different molecular weights revealed the presence of an experimen tal limit to the length of polynorbornene backbone chain and to the le ngth of the polystyrene graft. It is found that as the length of polys tyrene graft in the macromonomer is increased the length of polynorbor nene backbone chain in the graft copolymer is decreased an observation ascribed due to steric hindrance. The ROMP of macromonomers of differ ent molecular weight has been shown to be living allowing the synthesi s of tapered and block copolymers.