GRAFTING REACTIONS OF VINYL-ACETATE ONTO POLY[(VINYL ALCOHOL)-CO-(VINYL ACETATE)]

The grafting preference of vinyl acetate onto the methine carbon of po ly(vinyl alcohol) (PVOH) versus the acetate group of poly(vinyl acetat e) (PVAc) was determined as part of an attempt to prepare novel branch ed PVOH from partially hydrolyzed PVAc. The results showed long chain grafting on the acetate groups of the PVAc units rather than the methi ne carbons of the PVOH or PVAc units. Decreasing the monomer or initia tor concentration decreased the molecular weight of the graft copolyme r formed. Of the initiators studied, ammonium persulfate gave the larg est increase in copolymer molecular weight. Both hydrolysis and reacet ylation combined with gel permeation chromatography (GPC) and C-13-NMR of the fully hydrolyzed material were used to estimate the number and location of grafts. (C) 1996 John Wiley & Sons, Inc.