Radiation can create atomic-scale defect states in polymers, leading to changes in their optical, electrical and mechanical properties. Recent studies of polymers have shown that these defect states are sensitive to oxygen or water exposure. It is believed that oxygen cause the number of defect states to decrease and the polymers to revert to their original states. However, the time scale of this regression is not known. This experiment quantified the time that it takes five polymers to recover and the extent of said recovery; polypropylene (PP), low density polyethylene (LDPE), fluorinated ethylene propylene (FEP), polymide (PI), and poly ether ether ketone (PEEK). In order to study the regression optical transmission data were taken using a StellarNet UV/VIS Spectrometer. Optical data were collected at different intervals of time and then compared in order to quantify the time frame of the regression. Failure to account for this time-dependent recovery in radiation studies may result in inaccurate results and has called into question previous studies involving radiation effects in polymers where exposure times were not recorded.
Nelson, Alexandra Hughlett, "Relaxation of Radiation Effects in Polymers" (2019). Physics Capstone Projects. Paper 99.