Radiation induced degradation of polymers - An approach by using liquid paraffins as a model system

Paraffins, n-hexadecane and squalane, were employed as a model of polymers and radiation induced reactions in the polymers have been simulated. After vacuum irradiation, products were identified and their yields were determined by a variety of techniques. Ln the presence of the aromatic additives, the reduction of the degradation, so called protection effect: was clearly observed. Both energy and charge transfer play important roles in the protection effect. The same system was adapted to the irradiation under aerated condition in order to clarify the radiation induced oxidation. Furthermore, corresponding experiments using polypropylene were also performed and validity of the model system and phase effect were discussed. On the basis of the above results, it was revealed that the model experiment is valuable to understand the radiation induced reactions in polymers, especially amorphous phase of the polymers. Recently, the same model system has been extended to the thermal degradation at the temperature ranges of 300 - 400 degrees C. When radiation was introduced, both a significant acceleration of the degradation and an enhancement of H-2 evolution were clearly observed. This is suggesting a potential application of radiations to the degradation of polymers at elevated temperatures.