Effect of Brown Vulcanized Vegetable Oil on Ozone Resistance, Aging, and Flow Properties of Rubber Compounds

The addition of accelerator to vegetable oils during the preparation of brown V.V.O. results in a decrease of the free sulfur and the acetone extract values of the obtained V.V.O. In addition, the reaction time necessary to achieve the gel state is reduced. NR vulcanizates containing brown V.V.O. based on soybean oil are superior in retention of their tensile strength and 100% modulus after aging to those containing V.V.O. based on boiled linseed oil and dehydrated castor oil. The heat resistance of NR vulcanizates which contain brown V.V.O. increases as the amounts of the free sulfur and the acetone extract in the V.V.O. decrease. Addition of small amounts of brown V.V.O. to NR and SBR compounds helps to maintain the tensile strength after aging. However, the addition of high concentrations of the V.V.O. reduces the aging properties. The addition of brown V.V.O. based on soybean oil and TMTD to NR compounds used for the manufacture of printer rolls and rubber hoses enhances the ozone resistance of the rubber vulcanizates. Furthermore, the addition of this type of V.V.O. to NR and SBR compounds is advantageous because of: (1) delay of the onset of melt fracture, (2) reduction of extrudate swell, (3) smoother extrudate surfaces, (4) dimensional stability of NR and SBR extrudates.