Influence of ultraviolet radiation on polystyrene

The mechanical, structural, and morphological properties of polystyrene under fatigue combined with accelerated aging were investigated. Modifications produced by irradiation were evaluated by physical and mechanical tests. The results revealed that under fatigue condition (tension–tension) combined with exposure to the most intense sun ultraviolet (UV–B) radiation interval of wavelength from 280 to 320 nm, in the period of 336 and 575 h, the mechanical resistance was found lower when compared to polystyrene not irradiated. Changes in the properties of the degraded materials, such as reduced molecular mass due to chain scission and increased crystallinity were evidenced. The predominant failure mechanism in mechanically fractured specimens was also influenced by irradiation and the hardening of the surface layer was characterized by microhardness Vickers.