Service life prediction of rubber belt conveyor using kinetics approach

Abstract

Rubber offers adjustable mechanical properties so that widely used as an engineering material, such as belt conveyor. During application, rubber belt conveyor is subjected to various forces and exposed to different environments that lead to degradation. Therefore, the estimation of the service life of rubber product is important. In this study, belt conveyor cover was made of natural rubber blended with ethylene propylene diene monomer (NR/EPDM). The blend was prepared by controlling the curatives migration in order to get balanced properties. Service life estimation was carried out by accelerated aging in an air-circulated oven at 70, 85, 100, 115 and 130 °C for times ranging from 3 to 14 days depending on aging temperature (ISO 11346:2014). The hardness of the blend was monitored and its changes were employed in the estimation. Arrhenius relation was applied to express the degradation kinetics of the belt conveyor. Crosslinking has dominated the degradation mechanism because hardness tended to increase by aging time and temperature. It was assumed that the changes in hardness following the second-order reaction. The service life of the belt conveyor can be estimated using the equation:t=(X1+X)CA0(exp(−6.1022−2740.2RT)) where, X is the conversion (allowable remaining hardness), H0 is the initial hardness and T is the absolute temperature in which the belt. Service life was greatly affected by temperature and the end of life (EOL) criterion. The activation energy of degradation was 22.78 kJ/mol.