Block copolymerization of tert-butyl methacrylate with alpha,omega-difunctionalized polystyrene macroiniferter and hydrolysis to amphiphilic block copolymer

The block copolymerization of tert-butyl methacrylate (tBMA) with a difunct ionalized polystyrene (PS) macroinitiator it as investigated. The polymeriz ations were performed under UV light irradiation using PS bearing alpha- an d omega -functionalized end groups containing diethyldithiocarbamyl groups as a macroiniferter. Kinetic studies indicate the molecular weights of trib lock copolymers increased linearly with the conversion. Block copolymers wi th different lengths of PtBMA segments were easily prepared by varying the ratio of tBMA and PS macroiniferter or by controlling the monomer conversio n. The formations of block copolymers were characterized by gel permeation chromatographic, H-1 NMR, and DSC analyses. PtBMA segments of the triblock copolymer were subsequently hydrolyzed quantitatively to poly(methacrylic a cid) segments using concentrated HCl as a catalyst in a refluxing solution of dioxane, and then an amphiphilic ABA triblock copolymer was produced. (C ) 2001 John Wiley & Sons, Inc.