Oxygen and air have been interchangeably used as the purge gas in the
determination of carbon black content in polyethylene. This study show
s that accuracy of the carbon black filler content is significantly af
fected by the choice of oxygen as the purge gas used to oxidise the ca
rbon filler. It is believed that the difference in the density of the
oxygen give rise to the buoyancy effect. Air, having closer density to
the initial nitrogen purge gas in the analysis, is the better choice
for purge gas for accuracy of analysis and reproducibility of results.
(C) 1997 Elsevier Science B.V.