The importance of solvent polar character on the synthesis of PMMA-b-PBA block copolymers by atom transfer radical polymerization

The synthesis of diblock copolymers using atom transfer radical polymerizat ion (ATRP), of methyl methacrylate (MMA), and butyl acrylate (BA), is repor ted. These copolymers were prepared from bromo-terminated macroinitiators o f poly(MMA) and poly(BA), using copper chloride, CuCl,/N,N,N ' ,N " ,N " -p entamethyldiethylenetriamine (PMDETA), as catalyst system, at 100 degreesC in bulk and in benzonitrile solution. The block copolymers were characteriz ed by means of size exclusion chromatography (SEC), and H-1-NMR spectroscop y. The SEC analysis of the synthesized diblock copolymers confirmed the imp ortance of solvent on the molecular weight control. In addition, differenti al scanning calorimetry (DSC), measurements were performed, showing for all the copolymers a phase separation. (C) 2001 Elsevier Science Ltd. All righ ts reserved.