Effects of microtoming on oxidation of ultra high molecular weight polyethylene (UHMWPE)

摘要

It has been found that the rate of oxidation, as measured by the growth of the carbonyl band of oven aged microtomed UHMWhE films, is dependent on the velocity at which the films are microtomed. The same observation was made when real time chemilumines- cence measurements were performed in air at 120℃. The lower the cutting velocity, the faster the oxidation. By using NO derivatisation of unaged films, it was discovered that the hydroperoxide contents were also higher the lower the cutting velocity was. The knife used was quite blunt and left scratch marks on the films. When a sharper knife was used, no clear correlation could be found between the cutting conditions and the rate of oxidation. The films cut with the sharp knife did, however, also contain hydroperoxides. The most probable explanation of the observation that additional hydroperoxides were formed during cutting with the blunt knife is oxidation induced by the cobalt present in the tungsten carbide knife. It was found that the oxidation of the films was accelerated by just placing the knife on top of them during oven ageing.