Further studies on the thermal decomposition of AIBN-implications concerning the mechanism of termination in methacrylonitrile polymerization

Abstract

The products formed during thermal decomposition of AIBN-α-13C at 60° in benzene and dimethyl sulphoxide have been identified and quantified by 13C-NMR. Analysis of the oligomeric products demonstrates that there is selectivity in the reaction of oligo(methacrylonitrile) radicals (5) with cyanoisopropyl radicals (1). There is a marked preference for C-N coupling over C-C coupling and the major product observed results from combination of the nitrogen of 5 with the carbon of 1. The reaction kinetics of AIBN decomposition and product formation have been analysed to yield absolute rate constants (60°, benzene) for ketenimine decomposition and for the addition of 1 to methacrylonitrile. The impl..