STUDIES ON CONTROLLED OXIDATION OF LOW-MOLECULAR-WEIGHT POLYETHYLENES

The low molecular weight by-product of a high-density polyethylene pla nt (slurry process in hexane, Ti-based highly-active catalysts) was su bjected to controlled oxidation by air bubbling into the polymer melt maintained under stirring at constant temperature (130-170-degrees-C). Oxidized polyethylene waxes having various oxidation degree, i.e. aci d number up to 60 mg.KOH/g and saponification number up to 120 mg.KOH/ g have been obtained under different reaction conditions. Oxidation te mperature and polymer/air ratio proved to be the main parameters that control the process. Inhibition and catalytic effects have been also s tudied as well as the dependence of the oxidation Process on the like of the starting low molecular weight polyethylene. The results have be en used to develop an industrial process for producing oxidized polyet hylene waxes with useful properties and applications.