A REVERSED-PHASE HIGH-PRESSURE LIQUID-CHROMATOGRAPHIC METHOD FOR ANALYSIS OF ADDITIVES IN POLYOLEFINS

The key elements of the technique are the use of a mobile phase of constant composition (83% acetonitrile, 15% tetrahydrofuran, 2% acetic acid) and simultaneous UV and refractive index (RI) detection. The ratio of UV to RI response provides an additional identification which, together with the retention times, results in an excellent qualitative method. The quantitative aspects of the method were evaluated by analyzing three polypropylene reference samples containing typical additive packages. Most of the additives were quantitatively recovered from the polymer. Those that did not appear to be degraded into other products could be observed in the liquid chromatograms.