Effect of inorganic additives on some properties of NBR vulcanizates

Abstract

PurposeThe purpose of this paper is to study the effect of incorporating some inorganic fillers, namely aluminium oxide and aluminium hydroxide on the rheological, mechanical and thermal behaviour of acrylonitrile‐butadiene rubber (NBR) vulcanizates.Design/methodology/approachFor improving physico‐mechanical properties of NBR vulcanizates, various compositions were made by incorporating different concentrations of employed fillers with NBR. These properties included the torque, cure time, tensile strength, elongation at break, swelling, diffusivity, as well as thermal behaviour of the loaded and unloaded NBR with fillers were characterised.FindingsThe incorporation of the two investigated fillers improves the thermal behaviour of the vulcanizates, especially aluminium hydroxide. All samples showed more or less a first order decomposition kinetics, for which the activation energy ranged from 177 to 187 kg/mol.Research limitations/implicationsNBR is extensively used industrially for its single, most important property, which is an exceptional resistance to attack by oils and solvents. However, incorporation of fillers in (NBR) leads to the development of improved, competitive properties of the vulcanizate. A further study must be carried out on the flame retarding effect of the fillers, beside the effect of surface treatment of the fillers on the dispersibility and physico‐mechanical properties of the vulcanizates.Practical implicationsThe use of two investigated fillers provided a simple and practical solution to improving the resistance to swelling in motor and break oil as well as the thermal behaviour of the NBR.Originality/valueThe use of these fillers was novel and could be used in many rubber industries especially in gasket and oil seals.