Carboxyl-terminated butadiene acrylonitrile (CTBN) liquid rubber/epoxy (diglycidyl ether of bisphenol-A: DGEBA) / diamino diphenyl methane (DDM) resins, in which CTBN was 60 wt % as the major component, were formulated to evaluate the damping and adhesive properties. In cases where acrylonitrile (AN) was 10 similar to 18 mol % as copolymerization ratio in CTBN, the blend resins showed micro-phase separated morphologies with rubber-rich continuous phases and epoxy-rich dispersed phases. The composite loss factors (q) for steel laminates, which consisted of two steel plates with a resin layer in between, depended highly on the environmental temperature and the resonant frequencies. On the other hand, in the case where AN was 26 mol % in CTBN, the cured resin did not show clear micro-phase separation, which means the components achieve good compatibility in nano-scale. This polymer alloy had a broad glass-transition temperature range, which resulted in the high loss factor (eta > 0.1) for the steel laminates and excellent energy absorbability as the bulk resin in a broad temperature range. Also the resin indicated high adhesive strengths to aluminum substrates under both shear and peel stress modes. The high adhesive strengths of the CTBN/epoxy polymer alloy originated in the high strength and the high strain energy to failure of the bulk resin. (c) 2007 Wiley Periodicals, Inc.