Structural configuration-radiation stability relationship in the degradation of dumbbelled POSSs

The stability of the inorganic filler, polyhedral oligomeric sisesquioxane (POSS) powders modified as dumbbelled structures is analyzed. This study was conducted by γ-irradiation at four γ-doses, when the degradation of compounds was accomplished. The radiochemical stability was investigated by nonisothermal chemiluminescence. This procedure allowed to establish the sequence of radiation resistance as a characteristic feature in their applications as hybrid filler. The activation energies required for the delaying oxidation in the minor component were calculated. The consequences of defined molecular structure are discussed in the relation of the initiation of the material ageing in the formulation they would be included. The shown stabilization property is closely related to the activation energies that is required for the oxidation. The radiochemical modification occurred in dumbbell POSSs is characterized by the resistance of internal bridges rather than the degradation strength of spatial polyhedral configuration. The degradation profiles resulting from nonisothermal CL measurements are conditioned by the structural reasons and the diffusion of fed oxygen which maintains the spontaneous ageing of polymers, where these fillers would be added. The present results are appropriate proofs for the utilization of dumbbelled POSSs as suitable stabilizers for polymer materials subjected to radiation sterilization.