The effect of gamma irradiation on thermoplastic copolyesters.

Gamma irradiation affects colour, most notably b, and total transmittance of all of the copolyesters used in this study. The changes in colour and total transmittance increase with increasing dose level and CHDM content of the copolyester. These changes are only temporary and decay with time after sterilisation. At the highest dose level, all of the resins showed a slight decrease in molecular weight. Small changes in mechanical properties can be attributed to physical ageing that occurs at the slightly elevated temperatures associated with gamma irradiation. The mechanical properties are, however, stable after irradiation indicating no continued effects of the sterilisation process.