Elastomers for Tracked Vehicles - Development of Rubber Compounds for Bushings

摘要

After development of HNBR12, a patented formulation that doubled the service life of track pads, it has become necessary to improve the service life of bushings and roadwheels. The purpose of the work during FY 98 was to increase the service life of bushings and close the gap in service life between pads and bushings, while work during FY 99 will address the service life of roadwheels. A group of natural rubber compounds for bushings was developed to improve the reversion resistance of the conventional cure systems typically used in this application. In order to optimize performance and properties, a factorial experimental design of six factors at two levels for the curing and the antioxidant system was used. Properties deemed important for performance were selected and desirability functions defined for each one, after which a regression analysis was performed on the matrix to optimize the best features. The model was used to develop a set of formulations with enhanced properties. The optimization matrix produced a series of optimized formulations with improved performance properties, of which six were selected for fabrication and testing at the Keweenaw Research Center (KRC).