| The effects of combined neutron and gamma radiation on the viscoelastic behaviour of two industrial semi-crystalline PEEK grades (VICTREX 150P and 450P) were investigated. Tensile test samples were processed on an ENGEL55 injection moulder, then irradiated in a reactor pool environment, against the reactor vessel wall of the SLOWPOKE-2 facility at RMC, for exposures resulting in dosages ranging from 10 kGy to 320 kGy. First, the morphology of the irradiated resins was characterized by diffferential scanning calorimetry (DSC), X-ray diffraction and density measurements. Secondly, the viscoelastic behaviour of the material was studied at three thermodynamic states, in order to define the nature of the structural damage suffered by PEEK, by comparing its degree of molecular motion with the dose received. Therefore, standard mechanical testing was performed at room temperature, stress relaxation near the glass transition temperature (T... |
