?-OH polystyrene and ?-OH poly(n-butyl acrylate) as reactive stabilizers for the preparation of uniform polyurethane particles in a dispersed medium
Résumé
ω‐OH polystyrene (PS‐OH) and ω‐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 µm to 5 µm could be prepared by step‐growth polymerization of ethylene glycol (EG) and tolylene‐2,4‐diisocyanate (TDI) at 60 °C 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 ω‐OH PnBA was allowed to increase from 6000 to 15 000 g mol−1, the particle size was found to decrease from 2 µm to 200 nm.