X-ray irradiation-induced changes in cellulose triacetate

Samples from sheets of the polymeric material cellulose triacetate (CTA) have been exposed to X-ray radiation in the dose range 50–260 kGy. The modifications induced in the molecular and optical properties of CTA samples due to X-ray irradiation have been studied through different characterization techniques such as intrinsic viscosity, refractive index and color change studies. The results indicated that the cross-linking is the dominant mechanism at the dose range 100–260 kGy. This cross-linking led to an increase in the value of intrinsic viscosity from 1.28 for the non-irradiated sample to 1.41 for the sample irradiated with 260 kGy at 35°C, indicating an increase in the average molecular mass. This was associated with an increase in the refractive index. Additionally, the non-irradiated CTA samples showed significant color sensitivity toward X-ray irradiation. This sensitivity appeared by the change in the blue color component of the non-irradiated CTA film to yellow after exposure to X-ray up to 260 kGy. This is accompanied by a net increase in the darkness of the samples.