Ageing is one among the causes of thermoplastic, elastomer or thermoset parts damage. In this field, LRCCP provides assistance to manufacturers by allowing them to have better control over the functional decay of the parts, and predict the service life of the operating parts.

The study of ageing requires multidisciplinary skills and covers:

• Simulation of ageing under different environments: oxidant, thermal, photochemical, radiochemical, hydrolytic, under ozone, under mechanical stress.
• Heterogeneity: degree of oxidation and migration.
• Prediction of the long-term behaviour on the basis of accelerated ageing tests.

Prediction of the long-term behaviour may be processed by accelerated tests on the part or by calculation.

Analytical and predictive methodology	Investigation methods
Simulation of the long-term behaviour with accelerated ageing + Ageing characterization => structure/properties relationship	• chambers (temperature, radiations, oxygen, fluid, humidity…) • Functional test benches (ageing under mechanical stress) • climatic stations
	• global characterization (physical, mechanical) • local characterization (chemical, mechanical) • heterogeneity of ageing
Modelling of the ageing kinetics Service life prediction	• Arrhenius model (physico-chemical process) • WLF model (viscoelastic phenomena)

EXAMPLES

• Increase in the lifetime of gas hoses by 5 to 10 years,
• Gaskets of auto-blocking device of power plant,
• Assessment of hydro-swelling joint sealants for underwater tunnels
• Ageing of polymer based roofing membranes