Meaning
Oxidation byproducts of tris(2,4-di-tert-butylphenyl) phosphite form when secondary antioxidant additives consume hydroperoxides during high-temperature melt processing of polyolefins. Detecting irgafos 168 oxidized during analytical screening indicates that the active phosphite stabilizer performed its protective role against thermal degradation. Polymer analytical laboratories quantify the ratio of active phosphite to oxidized phosphate to assess remaining stabilizer life.
Excessive oxide concentrations reveal high thermal stress during compounding or moulding operations.
Oxidative Degradation
Hydroperoxide scavenging converts tris(2,4-di-tert-butylphenyl) phosphite into its corresponding phosphate structure through oxygen transfer. High levels of irgafos 168 oxidized confirm that melt temperatures or screw shear rates exceeded baseline compounding parameters. Monitoring degradation protects resin from thermal crosslinking and gel formation.
Phosphite Conversion
Liquid chromatography separates the residual active phosphite from its oxidized transformation product in polyolefin extracts. Calculating the ratio of active compound to irgafos 168 oxidized measures residual antioxidant protection capacity. Low active content warns that secondary processing will degrade polymer molecular weight.
Thermal History
Multiple extrusion cycles consume active antioxidants and accumulate oxidized chemical species within the polymer matrix. High irgafos 168 oxidized content signals extensive heat exposure, alerting compounders that virgin stabilizer re-addition is required for regrind reuse. Stabilizer tracking optimizes recycled resin blending ratios.
