Synthesis of macroazoinitiator by direct polycondensation for block copolymerization of styrene and butadiene

Macroazoinitiator (MAI) was prepared from hydroxy-terminated polybutadiene (HTPB) and 4,4′-azobis-4-cyanopentanoic acid (ACPA) by direct polycondensation in the presence of 1-methyl-2-chloropyridinium iodide (MCPI) at room temperature. This MAI proved to be an effective initiator for thermal polymerization of styrene at 60°C. The resulting products were characterized by viscosity measurements and both IR and NMR spectral studies. The ratio of styrene and butadiene units was calculated from NMR spectral data and scanning electron micrography. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2922–2933, 2001