Tribological Properties of Hydroxyl-Terminated Liquid Nitrile Rubber-Modified Polyurethane/Epoxy Interpenetrating Polymer Network Composites

A series of castor oil-based polyurethane (PU)/epoxy resin (EP) graft interpenetrating polymer network (IPN) composites modified by two kinds of hydroxy-terminated liquid nitrile rubber (HTLN) was prepared. A systematic investigation of the tribological properties of the two kinds of HTLN-modified PU/EP IPN composites was carried out through a pin-on-disk arrangement under dry sliding conditions. Experimental results revealed that the incorporation of HTLN can improve the friction and wear properties of PU/EP IPN significantly. Both the friction coefficient and wear loss decreased with increasing content of HTLN. The worn surfaces of the samples were analyzed using scanning electron microscope and a three-dimensional (3D) noncontact surface-mapping profiler; the results showed that the worn surfaces of the PU/EP IPN composites became smooth when the HTLN was added. The mechanisms for the improvement of tribological properties are discussed.