Chemical Ageing

Polymers in permanent offshore applications are required to function for their design life (20-50 years). Hence relevant material properties must remain within specification throughout this period. Short term laboratory tests designed to predict long term material performance rely on physical/chemical changes occurring in a predictable manner as an external variable is systematically altered. The acceleration is often achieved by raising temperature above the upper service limit. In this way, chemical reaction rates are quickened and long term performance may be inferred by applying an appropriate mathematical model (e.g., Arrhenius). Other accelerating factors include stress, frequency and concentration, with the choice depending on the application requirements.