Vinyl polymerisation of acrylonitrile by the vanadium(V)-glycerol redox system

Abstract

A kinetic study of the thermal polymerisation of acrylonitrile initiated by the redox system V⁵⁺ -glycerol in sulfuric acid and perchloric acid was made in the temperature range 35-45°C. The rates of polymerisation and V⁵⁺ disappearance wee measured with respect to their dependence on time, monomer, metal ion, glycerol, acid, and ionic strength. Experimental evidences provide support to a mechanism involving initiation by a free radical produced by the decomposition of the acyclic complex between V⁵⁺ and glycerol. The kinetics are consistent with a linear termination of polymerisation (1st order in respect of growing radicals) at higher concentration of V⁵⁺. The various rate and activation parameters were evaluated and an appropriate reaction scheme is proposed. The induction period and the polymerisation rate of the V⁵⁺-glycerol system were compared with those involving polyhydroxy alcohol systems such as sorbitol and mannitol.