Meaning
Analytical parameter measuring the time before the onset of exothermic oxidation in a polymer at a constant temperature. This measurement determines the thermal stability and degradation resistance of the material during its lifecycle.
Stabiliser Performance
Oxidative stability is a function of the antioxidant concentration within the polymer matrix. In the evaluation of polyolefins, oit determines the effectiveness of the stabiliser package under thermal stress. The test helps to identify if the material has been over-processed during compounding.
Thermal Trigger
Specific test conditions involve heating the sample in an inert nitrogen atmosphere before switching to a constant flow of oxygen. The instrument records the time elapsed between the oxygen introduction and the beginning of the degradation reaction. This point is identified by a sudden increase in heat flow as the polymer chains begin to break and react with the gas.
Durability Assessment
Long term performance of geomembranes and cable insulation depends on maintaining a minimum induction time throughout the service life of the part. Moulders use this value to verify that regrind material has not been excessively degraded by previous heat cycles. Short induction times indicate that a material has already undergone thermal stress or contains insufficient antioxidant protection.
