ω-OH polystyrene and ω-OH poly(n-butyl acrylate) as reactive stabilizers for the preparation of uniform polyurethane particles in a dispersed medium

omega-OH polystyrene (PS-OH) and omega-OH poly(n-butyl acrylate) (PnBA-OH) have been designed to act as both stabilizers and reactants in the synthesis of polyurethanes (PURs) in a dispersed medium. Uniform PUR particles with a size ranging from 0.2 mum to 5 mum could be prepared by stepgrowth polymerization of ethylene glycol (EG) and tolylene-2,4-diisocyanate (TDI) at 60degreesC in cyclohexane, in the presence of dibutyl tin dilaurate (DBTDL) as the catalyst and either hydroxy-terminated polystyrene (PS-OH) or hydroxy-terminated poly(n-butyl acrylate) (PnBA-OH) as the reactive stabilizer. Parameters such as the manner of addition of the reactants, the concentration and length of the stabilizer, were varied to tune the polyurethane particle size. While the molar mass of omega-OH PnBA was allowed to increase from 6000 to 15 000 g mol(-1), the particle size was found to decrease from 2 mum to 200 nm. (C) 2002 Society of Chemical Industry.