Structural modifications of polymers under the impact of fast neutrons

Fast neutron irradiations were performed at room temperature on a series of 13 polymer matrixes having great practical and academic interest. Polymers were irradiated with very low doses of 14 MeV neutrons deposited at reduced dose rate. The modifications of chemical structure of the polymeric matrixes resulting from irradiation were analyzed at the molecular scale by infrared and UV-visible spectroscopy. Particular attention was given to the oxidation occurring in irradiated matrixes during storage in the absence of light at room temperature. In addition the effects of irradiation on the chain arrangements in the polymers were analyzed by Differential Scanning Calorimetry.The most significant result obtained in this preliminary work was evidence that neutron irradiation with very low doses in the range ≈130-320 cGy could provoke structural changes. Indeed, depending on the matrixes, the formation of oxidation products along the macromolecular chains or the evolution of the polymer architecture, evidenced by changes of the T_g or of the crystallinity, was observed. The perspectives of this preliminary work are discussed.