Synthesis of poly(octadecyl acrylate-b-styrene-b-octadecyl acrylate) triblock copolymer by atom transfer radical polymerization

The synthesis of triblock copolymer poly(octadecyl acrylate-b-styrene-b-octadecyl acrylate), using atom transfer radical polymerization (ATRP), is reported. The copolymers were prepared in two steps. First, polystyrene was synthesized by ATRP using alpha,alpha'-dichloro-p-xylene/CuBr/bpy as the initiating system; Second, polystyrene was further used as macroinitiator for the ATRP of octadecyl acrylate to prepare ABA triblock copolymers in the presence of FeCl(2)(.)4H(2)O/PPh3 in toluene. Polymers with controlled molecular weight (M-n = 17,000-23,400) and low polydispersity index value (1.33-1.44) were obtained. The relationship between molecular weight versus conversion showed a straight line. The effect of reaction temperature on polymerization was also investigated, showing a faster polymerization rate under higher temperature. The copolymers were characterized by FTIR, H-1-NMR, DSC, and GPC and the crystallization behavior of the copolymers was also studied. (C) 2004 Wiley Periodicals, Inc.