Mossbauer studies of iron doped poly(methyl methacrylate) before and after ion beam modification

High-energy MeV ions from accelerators are known to produce drastic modifications in polymers. The typical effects include chain scissions, crosslinks, molecular emission and double bond formation. Poly(methyl methacrylate) was doped with Fe(III) and irradiated with 95 MeV O7+ ions. Fe-57-Mossbauer studies were done on the doped samples before and after irradiation. Before irradiation, no Mossbauer absorption was observed. The irradiated samples showed a good Mossbauer absorption, which seems to indicate that there is a significant interaction between the metal ion and the polymer matrix. Two possibilities exist at these doses (similar to 22 x 10(12) ions/cm): Fe(III) ions may be bridging the various polymer segments through crosslinking or amorphization of the sample leading to Fe-C bonding. Studies of FTIR, conductivity and glass transition temperatures on these samples support these observations.