GEL DOSE CURVES FOR POLYMERS UNDERGOING SIMULTANEOUS CROSS-LINKING AND SCISSION

This paper analyses the effect of molecular weight distribution on the relation between sol fraction s and absorbed dose D of ionising radiation. The usual Charlesby-Pinner relation with random cross-linking and scission was derived for the most probable initial molecular weight distribution (MBAR(w): MBAR(n) = 2), but is frequently used for very different distribution, to which it is not applicable. A modified version of this relation is presented for such other distribution, involving a virtual additional dose D-upsilon. Its success is assessed by comparing it with published experimental data for a number of polymers. The paper also compares these data with the empirical Zhang-Wanxi equation.