Blends of polypropylene (PP) and acrylonitrile butadiene rubber (NBR) were prepared with different weight compositions with a plasticorder at 180 degrees C at a rotor speed of 60 rpm for 8 min. The physicomechanical properties and mass swell of the prepared blends were investigated with special reference to the effects of the blend ratio. The prepared epoxidized linseed oil (EL) (i.e., E0.5L, E1L, E1.5L, and E2L using 0.5, 1, 1.5, and 2 mol H2O2/mole of unsaturation in linseed oil) and maleic acid anhydride (MAH) were melt mixed in various contents (i.e., 1, 5, 10, and 15 wt%) with a PP/NBR blend with a weight ratio of 70/30 and used as compatibilizers. The effect of the compatibilizer contents on the physicomechanical properties and mass swell of the binary blend was investigated. With an increase in the compatibilizer content up to 10 wt%, the blend showed an improvement in the physicomechanical properties and reduced mass swell in comparison with the uncompatibilized one. The addition of a compatibilizer beyond 10 wt% did not improve the blend properties any further. The efficiency of the compatibilizers (10 wt%) was also evaluated by studies of phase morphology (scanning electron microscopy). (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 118: 2056-2061, 2010