Relationship between rubber tear strength and filling system

Tear strength increases with decreasing carbon black particle size. For the same particle size, carbon blacks that give high elongation, i.e., those with a lower degree of structure, are favourable for the increase in tear strength. Increasing the amount of high abrasion-resistant carbon black in natural rubber leads to an increase in tear strength. When high abrasion-resistant carbon black is added to styrene butadiene rubber, a maximum value occurs and then gradually decreases. In general, the tear strength of synthetic rubber is significantly increased when carbon black is used for reinforcement. In general, the amount of carbon black required to achieve optimum tear strength is higher than the amount required to achieve optimum tensile strength. The use of isotropic reinforcing fillers, such as carbon black, white carbon black, white brilliant, Rieter's powder and zinc oxide, etc., results in higher tear strengths, while the use of anisotropic fillers, such as clay, magnesium carbonate, etc., does not result in high tear strengths.