Effect of X irradiation on optical properties of Teflon-AF
Radiation effects in optical-grade amorphous fluoropolymer, Teflon-AF, is investigated by UV-visible absorption and electron spin resonance (ESR) measurements. When irradiated with low-energy (40 kVp) X-rays at room temperature in air, Teflon-AF is found to develop a broad, structureless UV-absorption band in the wavelength interval 200-350 nm. While the UV absorption increases as a function of X-ray dose, with relative rates of approx 2 × 10-5 Gy-1 (1 × 10-5 Gy-1) in Teflon-AF 1600 (Teflon-AF 2400), its optical transparency for a given dose of 67.5 kGy, however, remains unaffected. Additional measurements conducted using electron spin resonance (ESR) technique reveal that the observed UV absorption is caused by the X-ray induced peroxy radical (POO . ̇). The results also suggest that the inclusion of dioxole monomer in the PTFE chain not only improves the optical clarity of Teflon-AF, as reported, but also increases its radiation tolerance. During a post-irradiation storage in air at RT for about 30 days the peroxy radical is observed to decay, with a concomitant decrease in UV absorption. A tentative model is proposed to explain the radiation damage and recovery mechanisms. © 1993.
Radiation Physics and Chemistry
Jahan, M., Ermer, D., & Cooke, D. (1993). Effect of X irradiation on optical properties of Teflon-AF. Radiation Physics and Chemistry, 41 (3), 481-486. https://doi.org/10.1016/0969-806X(93)90008-I