Mechanism and kinetics of grafting of macrodiisocyanate on to carboxyl-containing acrylonitrile copolymers

• Published in: Journal of applied polymer science 1979-07, Vol.24 (1), p.19-28
• Main Authors: Shalabi, S. E., Yan, G. A. Gabriel, Rogovin, Z. A.
• Format: Article
• Language: English
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.1979.070240103

The reaction of a carboxyl‐containing acrylonitrile copolymer with a macrodiisocyanate based on polypropylene oxide (Mn = 2000) in dimethylformamide (DMFA) and dimethylsulfoxide (DMSO) solutions was studied. The mechanism and main kinetic regularities of the grafting reaction were investigated. The reaction proceeds through formation of a mixed anhydride with its subsequent decomposition leading to liberation of CO2 and formation of graft copolymers. Carboxyl and nitrile groups of the copolymer take part in the reaction. A side reaction involving interaction of isocyanate groups of macrodiisocyanate with DMFA proceeds during synthesis of graft copolymers in DMFA solutions. The dependence of graft polymer yield on temperature, macrodiisocyanate concentration and on the catalyst/NCO ratio was determined. The activation energy of the grafting reaction is 22.9 kcal/mole. The specific viscosity of graft copolymers in DMFA solutions increases with the number of grafted chains.