Synthesis and characterization of PBMA-b-PDMS-PBMA copolymers by atom transfer radical polymerization

Poly(butyl methylacrylate)-b-poly(dimethylsiloxane)-b-poly(butyl methylacrylate) (PBMA-b-PDMS-b-PBMA) triblock copolymers were synthesized by atom transfer radical polymerization (ATRP). The reaction of ,-dichloride PDMS with 2-hydroxyethyl-2-bromo-2-methylpropanoate gave suitable macroinitiators for the ATRP of BMA. The latter procedure was carried out at 110°C in a phenyl ether solution with CuCl and 4,4-di (5-nonyl)-2,2-bipyridine (dNbpy) as the catalyzing system. The polymerization was controllable, with the increase of the monomer conversion, there was a nearly linear increase of molecular weight and a decrease of polydispersity in the process of the polymerization, and the rate of the polymerization was first-order with respect to monomer conversion. The block copolymers were characterized with IR and 1H-NMR and differential scanning calorimetry. The effects of macroinitiator concentration, catalyst concentration, and temperature on the polymerization were also investigated. Thermodynamic data and activation parameters for the ATRP were reported