Novel rigid poly(vinyl chloride) (PVC)/cross-linked acrylonitrile butadiene rubber (NBR) blend using copper (II) sulfate pentahydrate (CuSO4 center dot 5H(2)O) as cross-linking agent was prepared by melt mixing. Fourier transform infrared analysis showed that the coordination cross-linking occurred between NBR and CuSO4 center dot 5H(2)O in the PVC matrix, in which a novel morphology was first observed by scanning electron microscopy analysis. The thermal stability and degradation behavior of the PVC/NBR/CuSO4 center dot 5H(2)O blend were examined by means of dynamic mechanical thermal analysis and thermogravimetric analysis. It was found that the glass-transition temperature (T-g) of the PVC/NBR/CuSO4 center dot 5H(2)O blend was enhanced by adding the coordination cross-linked NBR into the PVC matrix. In spite of the onset decomposition temperature and the first rapidest decomposition temperature of the resultant blends reduced in comparison to neat PVC, the second rapidest decomposition temperature and the residues of the resultant blends were significantly enhanced. In addition, the thermal degradation kinetics and mechanical properties of the resultant blends were also investigated. (C) 2013 Society of Plastics Engineers