Journal of Engineering Science and Technology Vol. 15, No. 3 (2020) 2051 - 2061 © School of Engineering, Taylor’s University 2051 THE EFFECT OF CURE ACTIVATOR ZINC OXIDE NANOPARTICLES ON THE MECHANICAL BEHAVIOR OF POLYISOPRENE RUBBER NABEL KADUM ABD-ALI Material Engineering Department, College of Engineering, University of Al-Qadisiyah, Iraq E-mail:nabel.abdali@qu.edu.iq Abstract Zinc oxide is an effective material due to its unique physical and chemical properties. The present work use of a limited amounts of zinc oxide nanoparticles produced by sol-gel process as an alternative to conventional zinc oxide and investigated the effects of this material on the mechanical behaviour of rubber recipes including cis-Polyisoprene rubber vulcanized by sulphur. Results showed the possibility of using nanoparticles of zinc oxide produced by chemical method in smaller quantities to achieve better results than the conventional zinc oxide used with rubber recipes especially (0.3 and 0.4 pphr). Results of Aging and Swelling test confirm the validity of the use of this material and the results showed significant improvements in these characteristics. Tensile strength about 9.8, 11.2, 13.9, 15.4 and 15.7 MPa were observed at 0.1, 0.2, 0.3, 0.4 and 0.5 pphr respectively compared to 12.6MPa was observed at 4 pphr conventional ZnO. Also, the reduction ratio were 95%, 95%, 80%, 73%, 70% and 79% at aging time reach to 120h for the recipes 4 pphr (conventional), 0.1, 0.2, 0.3, 0.4 and 0.5 respectively, while the swelling characteristics shows better resistance at 0.3 and 0.4 recipes pphr ZnO NPs. in toluene at room temperature. Current work supports the trend towards reducing the amount of zinc oxide used in rubber compounds as a cure activators agent. Keywords: Aging, Cure activator, Polyisoprene rubber, Sol-gel process, Swelling, Zinc oxide.