Active Species in Radiation-irradiated Poly(vinyl alcohol) for Initiation of Graft Polymerization

Abstract

The amount of trapped radical in radiation-irradiated poly(vinyl alcohol) (PVA) has already been measured quantitatively in terms of ESR by other workers. However, when vinyl monomer was graft polymerized onto irradiated PVA, some part of trapped radical seemed to become partially effective for the initiation of graft polymerization as the other part of trapped radical was inactivated by the side-reaction, e.g., a recombination of radical and an attack of residual oxygen in this system.
This paper deals with an elucidation of the above-mentioned fact. A DPPH radical was allowed to react with irradiated PVA under the condition similar to graft polymerization. The amount of trapped PVA radical which seemed to initiate effectively graft polymerization was estimated from the amount of consumed DPPH radical. This value was about a tenth of that obtained in terms of ESR.