AbstractBecause of the structural dissimilarity, natural rubber (NR) and acrylonitrile–butadiene rubber (NBR) are immiscible, and compatibilizers are used during their blending. Neoprene or chloroprene rubber (CR) has a polar chlorine part and a nonpolar hydrocarbon part. Also, it has many advantageous properties, such as oil resistance, toughness, a dynamic flex life, and adhesion capacity. Hence, it is not less scientific to use CR as a compatibilizer in the blending of NBR with NR. Because many fewer studies on the use of neoprene as a compatibilizer in NR–NBR blend preparation are available, efforts were made to prepare 20:80 NR–NBR blends with CR with the aim of studying the effect of poly(ethylene oxide) (PEO)‐coated nano calcium silicate along with nano N‐benzylimine aminothioformamide and stearic acid coated nano zinc oxide in the sulfur vulcanization of the blends. The optimum dosage of the compatibilizer was derived by the determination of the tensile properties, tear resistance, abrasion resistance, compressions set, and swelling values. The tensile strength, tear resistance, and abrasion resistance of the gum vulcanizates of the blend were improved by the compatibilizing action of CR up to 5 parts per hundred parts of rubber (phr). In the case of the filled vulcanizates, the tear resistance, 300% modulus, hardness, and abrasion resistance increased with increasing dosage of nano calcium silicate. The elongation at break percentage decreased as expected when there was an increase in the modulus. Scanning electron microscopy was used to study the phase morphology of the blends. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012