The radiation crosslinking and scission of some polyphosphazenes

The radiation behaviour of four aryloxy and one arylamino polyphosphazenes has been studied. In particular the gel formation has been measured as a function of the absorbed dose. The data have been interpreted in the form of Charlesby-Pinner plots, modified using the Dole-Inokuti relationship for an initial Schulz-Zimm molecular weight distribution. All the samples fitted the model well with no concurrent scission. The G(X) values were determined from the corresponding Dsub(gel) values. The latter were obtained by extrapolation to S + Ssup(1/2)=2.0. A wide range of G(X) values was found depending on the molecular structure of the polyphosphazenes. Possible reasons for the results are discussed. (author)