Abrasion Resistance and Its Measurement

Abstract

Abstract Abrasion resistance is not a specific property of rubber, but depends both on the method of measurement and the machine used. The relation between abrasion resistance and the simpler physical properties, and the use of the regression technique whereby equations relating abrasion resistance, tensile strength, and hardness have been developed, are discussed. Twenty-one existing abrasion machines are reviewed and classified in one of four categories, and, wherever possible, an indication is given of the types of compound where good correlation with service is claimed. Most of the machines have been used for compound development work, but correlation with actual wear trials must be improved before the service life can be forecast accurately. Until the mechanism of abrasion is better understood the I.S.O. decision to adopt a simple method, e.g., du Pont, as a basis for standardization is sound. Work with eight sole and heel compounds and twelve tire treads shows that the order of merit obtained in the normal du Pont test is almost completely the reverse of service. With tire tread compounds, extraction of the test-pieces in ethanol-toluene-azeotrope improved the correlation with service. Further work with compounds of known service wear is required, and the extraction method in its present form does not improve the accuracy of any comparison of two compounds from different polymers, e.g., natural rubber and GR-S. The use of zinc as a standard material for checking the cutting power of the abrasive has been investigated and its use is not recommended for the du Pont type of machine.