Organic/inorganic hybrid nanostructured composites of liquid nitrile rubber-based quaternary ammonium salt-modified montmorillonite and epoxy resin: preparation and tribological behaviors

A new type of polymer derivative, carboxyl-terminated butadiene nitrile rubber-based quaternary ammonium salt (CTBN-QAS), has been synthesized and used for the functionalization of sodium montmorillonite (MMT-Na) via a cationic exchange process. The resulting CTBN-QAS-modified MMT (CTBN-QAS-MMT) exhibits exfoliated and/or intercalated structures as indicated by X-ray diffraction (XRD) analysis. Further CTBN-QAS-MMT was incorporated into diglycidyl ether of bisphenol A (DGEBA) with different loadings to produce organic/inorganic hybrid epoxy nanocomposites. Studies were conducted on tribological behavior and dynamic mechanical properties by ring-on-block wear tester and dynamic mechanical analysis, respectively. The results show that as-prepared nanostructured epoxy has better wear resistance and lower friction coefficient than pure epoxy polymer (EP), and the best wear resistance is obtained at 6 phr (parts per hundred) CTBN-QAS-MMT-modified EP. Wear surface morphology analysis shows that the friction mechanism is abrasive wear. Additionally, the good friction resistance and decreased wear loss are correlated with higher glassy storage modulus and lower tan delta. The improved tribological behavior is due to the formation of hybrid organic/inorganic nanostructured epoxy material.