Preparation and characteristics of NR/EPDM rubber blends

Abstract

Ethylene propylene diene monomer rubber (EPDM) was modified with maleic anhydride (MA). Benzoyl peroxide was used as an initiator. Then the produced MA-EPDM was mixed with natural rubber (NR)/EPDM blends with various compositions. The scanning electron micrographs demonstrated that the addition of MA-EPDM (10 phr) improved the compatibility of the NR/EPDM blends and thereby led to a finer phase morphology. The intrinsic viscosity measurements also confirmed the compatibility of that blend. The heat and UV radiation resistance of the NR/EPDM compatibilized blend were determined in terms of physico-mechanical properties of the blends with various blend ratios. The NR/EPDM (25/75) blend showed the best thermal aging resistance. However, the 50/50 blend possessed the best resistance against UV irradiation. The compression recovery study revealed that 25/75 (NR/EPDM) compatibilized blend vulcanizate possessed the highest percent compression recovery at 3, 10, and 18% compressions. The compression of swollen specimens in motor oil indicated that the percent recovery was almost independent of the NR/EPDM blend ratio at high compressions investigated.