W. Burger et al., RADIATION DEGRADATION OF FLUOROPOLYMERS - CARBOXYLATED FLUOROPOLYMERSFROM RADIATION DEGRADATION IN PRESENCE OF AIR, Journal of applied polymer science, 48(11), 1993, pp. 1973-1985
Irradiation of PTFE by accelerated electrons in the presence of air gi
ves rise to a carboxylated structures at doses above 50 kGy. The surfa
ce of the irradiated suspension polymerizate TF 1750 is more carboxyla
ted than is the bulk. The influence of oxygen content and radicals is
much higher than it is with the emulsion polymerizate TF 2025. The mel
ting point of irradiated PTFE increases at low doses. Electron-beam ir
radiation of the fluorinated copolymers perfluoroalkoxy (PFA) and tetr
afluoroethylene-hexafluoropropylene (FEP) leads to loss of fluorine. I
n all cases, the oxygen uptake was higher near the surface than in the
bulk. PFA was better carboxylated than was FEP. The fact that cross-l
inking was not found to a measurable extent up to 800 kGy suggested th
at double-bound formation was important. The main effects of electron-
beam irradiation are chain scission, oxidation, and unsaturation depen
ding on dose rate, oxygen content, and particle size.