Raman and FT-IR investigation of neutron and fission-fragment irradiated DAP polymer

Abstract

The polymer Diallyl Phthalate (DAP), commonly used as solid-state nuclear track detector (SSNTD), has been characterized via optical microscopy and Raman and FT-IR spectroscopies in three distinct processes: i) without irradiation; ii) irradiated by neutrons and induced fission fragments and iii) as a function of the chemical etching time. The detectors were exposed to fission fragments from the induced fission of 235U and to the neutrons themselves. The optical microscopy provides information about the morphological changes, while the spectroscopic techniques provide physical and chemical information over the detector molecular structure. The irradiation and chemical etching induces molecular degradation and cross-linking of the detector chemical structure as observed in the Raman and FT-IR analyses. According to the spectral profile analyses, the strength of the functional groups OCOO, CH, CHCH, CCH, COC, CCH3, C(CH3)2, CCH3, CO, CH2 decrease and additional CO2 gases and OH groups are produced. Therefore, the characterization process performed in this work is essential to better comprehend the behavior of the DAP molecular structure under irradiation and chemical etching and also to better understand the track formation process which is related to the etching kinetics.