Properties of Natural Rubber/Chloroprene Rubber Blend for Rubber Fender Application: Effects of Blend Ratio

Natural rubber is widely known to possess good mechanical properties. However, due to the existence of numerous reactive double bonds on the molecular backbone, natural rubber is highly susceptible to degradation by thermal aging. To overcome such shortcomings, natural rubber is frequently blended with synthetic rubbers such as chloroprene rubber. Chloroprene rubber is one of the most important specialty rubber for nontire application, for example rubber fender. The present study investigates the effects of two different blend ratios of natural rubber (standard Indonesian rubber or SIR 10) and chloroprene rubber on the cure, tensile properties, and morphology of rubber blends. The blends of SIR 10/chloroprene rubber are prepared by using laboratory kneader and laboratory two-roll mill. Rubber blending is made from mixture of natural rubber SIR 10 and synthetic rubber chloroprene rubber with variation of SIR 10/chloroprene rubber ratio PF1 100/0; PF2 70/30; PF3 30/70; PF4 0/100 phr. Furthermore, each variable is tested to determine the rheological and mechanical properties including tensile strength, elongation at break, hardness, and compression set. The addition of chloroprene rubber also causes an increment in the tensile strength and elongation at break. However, only PF3 shows satisfied result compared to the requirements standard (ISO 17357-1:2014 Ship and Marine Technology-Floating Pneumatic Rubber Fenders).