PHYSICAL MODIFICATION OF ELASTOMERS TO IMPROVE THEIR TRIBOLOGICAL PROPERTIES

An attempt is made to obtain an elastomeric material for shaft seals which does not demand permanent lubrication. Composites based on oil-resistant elastomers (nitrile rubber (NBR), chlorosulphonated polyethylene (CSM) or fluorine rubber (FPM)) were physically modified to improve the tribological properties of their vulcanizates. Different substances and methods of application were tested. The influence of the modification on the coefficient of friction and the wear of the samples was measured in dynamic conditions by means of a ring-on-disc apparatus. The best results were obtained form surface modification by molybdenum disulphide (MoS2) which until now has mainly been used for rigid, stiff materials. The results obtained have been interpreted taking into consideration both the adhesional and hysteretical properties of the system. The preparation methods of the special suspensions or pastes for covering the rubber surface and an explanation how they work was the main aim of the study.