Photocatalytic fatigue of the polymer nanocomposites

Abstract

We discuss the change in mechanical properties of polymeric nanocomposites with photoactive components caused by solar range lighting. Given degradation photoassisted processes are related with the semiconductor nature of component photoactive particles as photocatalysts. Semiconductor particles can be transferred into electron-exited states due to light quanta absorption. One possible way out from these states is through redox electrochemical reactions with neighbor molecules. The redox reactions can produce transformations of polymer structure and composition, decreasing its mechanical strength. The term “photoca-talytic fatigue” denotes a special case of the photo-degradation of polymers resulted only in a change in the strength value of the material. We review not numerous published data on investigations of changes in mechanical properties of polymeric nanocomposite, and mainly in the strength value, arisen from solar range light irradiation. We compare the degradation processes of polymeric nanocomposites containing photoactive components and of the high-cycle fatigue in metals. Likewise, we propose the use of equations of metal high-cycle fatigue curves as a possible approach to mathematical modeling of the processes of polymeric nanocomposites photodegradation. In this, the number of cycles is substitution with exposure time. Especially, the high-cycle fatigue curve equation for the samples with stress concentrations is considered. The experimental parameters of the “photocatalytic fatigue” equation for polymer nanocomposites containing photoactive components are calculated using the Monte Carlo method.