COMPARATIVE ANALYSIS OF THE MECHANICAL PROPERTIES OF CLAY- AND CARBON BLACK-REINFORCED HNBR VULCANIZATES OBTAINED BY THERMAL AND THERMO-RADIATION VULCANIZATION

Abstract

This study investigates the mechanical and thermal properties of clay- and carbon black-rein- forced hydrogenated nitrile butadiene rubber (HNBR) vulcanizates prepared by thermal and ther- mo-radiation vulcanization. The effects of different irradiation doses (100, 200, 300, and 400 kGy) on the crosslink density, gel content, swelling, and mechanical properties were analyzed. The re- sults show that radiation vulcanization significantly improves the crosslinking efficiency, with 300 kGy being the optimal dose. Carbon black-filled samples exhibit higher mechanical strength, lower swelling, and better thermal stability compared to clay-containing samples due to improved net- work formation. Thermogravimetric analysis (TGA) confirms that radiation vulcanization shifts the onset of thermal degradation to higher temperatures, especially at 300 kGy, while excess irradiati- on at 400 kGy leads to degradation of the structure at lower temperatures. Fourier transform infra- red spectroscopy (FTIR) further reveals the molecular changes induced by radiation. The results highlight the importance of filler type and radiation dose selection to optimize the properties of HNBR elastomers in high-performance applications.