Effect of aging on the tensile and tearing behavior of NanoClay-Reinforced hydrogenated nitrile butadiene rubber

This study investigates the effects of nanoclay reinforcemet and thermal aging on the mechanical properties of Hydrogenated Nitrile Butadiene Rubber (HNBR). Four different compositions were examined: pristine HNBR and HNBR with 5%, 10%, and 15% nanoclay content by weight. The samples were subjected to thermal aging at 150°C for 70 h according to standard of ISO 188. Comprehensive mechanical characterization was performed through tensile tests (ASTM D638), tear tests (ASTM D624) and compression tests (ASTM D395 B). Also, Rheometry test is carried out to determine the optimal curing temperature and time for a given compound. The experimental results revealed that moderate nanoclay content (5-10%) enhanced aging resistance while maintaining optimal mechanical properties. Specifically, samples with 5% nanoclay exhibited the smallest reduction in tensile strength after aging (18.2% decrease) compared to the pristine HNBR (28% decrease). However, with post-aging all compositions showed significant increases in elastic modulus, with increases ranging from 137% to 160.74%. The tear strength analysis demonstrated that nanoclay incorporation slightly reduced initial tear resistance but provided better stability during aging. Numerical simulations using the Marlow model in ABAQUS software showed good agreement with experimental results, validating the computational approach. The findings suggest that optimal nanoclay content for balancing mechanical properties and aging resistance lies between 5-10%, while higher concentrations (15%) led to diminished performance due to potential agglomeration effects.