Block copolymers derived from azobiscyanopentanoic acid. X. Synthesis of silicone–vinyl block copolymers via polysiloxane(azobiscyanopentanamide)s

The synthesis of silicone–vinyl block copolymers has been studied by the use of poly(azo‐containing siloxaneamide)s (abbreviated as PASAs), i.e., polysiloxane (azobiscyanopentanamide)s as macroazoinitiators. PASAs with number‐average molecular weight of 12000–31000 and with siloxane chain lengths of 250–9800 were prepared by the condensation of azobiscyanopentanoyl chloride and α,ω‐bis(3‐aminopropyldimethyl)polysiloxanes in equimolar feeds. Several kinds of silicone–vinyl block copolymers were synthesized by radical polymerization of vinyl monomers such as methyl methacrylate, styrene, and vinyl acetate, in the presence of PASA in homogeneous media. The block copolymers with siloxane contents up to 30 mol % were then characterized on the basis of infrared absorption, proton NMR spectra, and gel permeation chromatography.