Volatile evolution induced by energetic He++ ions in a poly(ester)based polyurethane

Irradiation of polymer samples using an accelerated beam of He++ ions passed through a 10 μm thick window of havar foil has been performed. Such an irradiation simulates the effects of large α radiation doses. The experimental set up was designed so that the irradiated material was contained within a small sample chamber, which was isolated from the main vacuum chamber of the ion beam by means of the foil window. A mass spectrometer linked directly to the sample chamber facilitated analysis of gaseous products evolved from the materials as a consequence of irradiation. Samples of a poly(ester) based poly(urethane) polymer evolved mainly CO2 along with a number of higher mass volatile species. Assignment of chemical structures to the main molecular ions has allowed deductions about the chemical processes underlying radiation induced change to be made. Furthermore, identification of trends in volatile production affords information about radiation induced crosslinking reactions, which do not directly result in the production of volatile species to be deduced.