Ageing of polymer and composite material is an irreversible process, which occurs when the material is exposed to particular environmental conditions. Ageing is dependent on temperature, exposure to seawater, exposure to air (ozone degradation where applicable) and ultraviolet (UV) radiation. The ageing process is characterized by a change in properties, such as reduction in strength or ductility, and embrittlement or softening. In addition, the physical properties of the polymer or composite can be significantly altered by migration of plasticizers.
Source: API RP 17L2, Recommended Practice for Flexible Pipe Ancillary Equipment, First Edition, March 2013. Global Standards