Study of the Mechanical Properties of Natural Rubber Composites with Synthetic Rubber Using Used Cooking Oil as a Softener

This research aims to study the mechanical properties of natural rubber composites with nitrile butadiene rubber and ethylene propylene diene monomer rubber. Composite fillers consisted of kaolin, and softener using used cooking oil. The study was carried out by the method of mastication, vulcanization, and maturation of the compound into rubber vulcanizates. The vulcanization and mastication process is carried out in the open mill. The maturation of the compound into rubber vulcanizates from the results of mastication and vulcanization was carried out using semi-automatic heat press and press at a temperature of 130 °C ± 2 °C for 17 min. Based on data from testing the mechanical properties of five samples from five formulas, the mechanical properties of composite rubber are affected by the ratio of natural rubber, synthetic rubber, kaolin, and used cooking oil as a softener. The difference in the results of vulcanizates rubber testing of natural rubber composites with synthetic rubber is not only influenced by the ratio of the composite, but also by the degree of cross-linking between the material molecules.