GRAFT-COPOLYMERIZATION OF METHYL-METHACRYLATE BY LITHIUM DIISOPROPYLAMIDE-TREATED POLY(VINYL PROPIONATE)

The anionic grafting of methyl methacrylate (MMA) onto poly(vinyl propionate) (PVPr) was achieved after treatment of the latter with lithium diisopropylamide (LDA). The percentage of grafting of the polymer was between 120 and 730%, no homopolymers being obtained. The degree of lithiation was determined to be 26 mol-% with respect to monomer units by means of deuterolysis. The hydrolysis of the graft copolymers results in the side-chain polymers (PMMA) and poly(vinyl alcohol) (PVA). The average number of branches in the graft copolymer increases from 1 to 7 with increasing percentage of grafting. M(W)BAR/M(n)BAR of the side chain poymer is between 2,0 and 6,7. The low reactivity of the lithium sites may be caused by aggregation of enolates, leading to the broadening of the molecular weight distribution.