WATER LUBRICATION OF POLYURETHANE GRAFTED WITH DIMETHYLACRYLAMIDE FOR MEDICAL USE

The tribological properties of poly(N,N,dimethylacrylamide) (DMAA) grafted onto polyurethane in water were investigated. Scanning electron microscope images show that the entire surface is coated with the DMAA layer and the layer survives after a series of wear tests. The friction of the grafted material against an alumina ceramic was measured with a thrust-collar-type apparatus. For a densely grafted surface, the coefficient of friction in distilled water was about 0.04. Such a low friction was realized not only at low speed but also at the moment of start-up. The water absorbed by the layer plays an important role in lubrication when it exudes slowly from the layer. A medical device covered with a DMAA layer is promising, because it may enable painless insertion, precise operation and the protection of tissue from injuries.