Meaning
Chemical assays quantify the concentration of reactive oxygen species within an organic peroxide solution or masterbatch. This measurement determines the potency of the catalyst used to initiate crosslinking or degradation in polymer processing. The peroxide active oxygen titration process provides a percentage value that represents the weight of active oxygen available in the sample.
Assay Value
Laboratory technicians use a redox titration method where a sample is dissolved and reacted with an indicator. The amount of titrant required to reach the end point reveals the chemical strength of the peroxide. Monitoring the peroxide active oxygen titration result ensures that the moulder adds enough initiator to achieve the desired melt flow or cure rate.
This process typically involves iodine liberation where the peroxide reacts with potassium iodide in an acidic medium before the resulting iodine is titrated with sodium thiosulfate.
Crosslinking Control
Polymers like polyethylene require a precise amount of active species to form strong molecular bonds. If the oxygen content is too low, the plastic will remain soft and lack the necessary structural integrity. Regular peroxide active oxygen titration checks prevent failures in the field by verifying the chemical activity of every incoming batch.
Shelf Stability
Organic peroxides are thermally sensitive and lose their effectiveness over time when stored in warm conditions. A decrease in the titration value indicates that the material has partially decomposed and may no longer perform as expected. Because high temperatures accelerate this loss, peroxide active oxygen titration is a reliable method for verifying the quality of older inventory.
