Study of the long term effect of high gamma doses in the crystalline phase of P(VdF-TrFE) copolymers

Differential Scanning Calorimetry (DSC) and X-ray diffraction (XRD) of gamma irradiated poly(vinylidene fluoride-trifluoroethylene) copolymer [P(VdF-TrFE)] have been studied in connection with the use of material in industrial high gamma dose measurement. Interaction between radiation and P(VdF-TrFE) results in a decrease of its crystallinity together with the simultaneous formation of C=C conjugated bonds It has been found that the melting latent heat (L-Melt) of the crystallites is unambiguously related to the value of absorbed dose The DSC technique can be used to evaluate high gamma doses ranging from 1.0 kGy to 1 0 MGy. The relation between L-Melt and gamma doses can be fitted by an exponential function for measurements taken until 3 months after irradiation After this time, the relation can be fitted by a linear function for periods at least of one year X-ray diffraction revealed an expansion of the beta-phase unit cell of 5% in the b direction for gamma doses between 250 and 500 kGy. The results presented highly increases the possibility of using the melting latent heat of P(VdF-TrFE) copolymer in high dose dosimetry (C) 2010 Elsevier BV All rights reserved