Design and preparation of sulfur vulcanized polyamide 66 cross-linked nitrile butadiene rubber networked and its application in blending with graphene oxide

Abstract

This study investigates the effect of a multiphase crosslinked network structure formed using a sulfur vulcanization system on the vulcanization, thermal stability, and mechanical and tribological properties of nitrile butadiene rubber/polyamide 66/graphene oxide (NBR/PA66/GO) composites. Differential scanning calorimetry and glass transition temperature (Tg) were used to evaluate thermal stability. Samples doped with 1 phr of sulfur (1S) have the best "residual carbon at 800 °C" and Tg. The surface morphology after friction wear was characterized using scanning electron microscopy and a 3D profilometer. The tensile and tear strengths of 1S increased by approximately 74 % and 39 %, respectively, compared to those of 0.5S. The coefficient of friction was reduced by approximately 61 % compared to that of 3S. Molecular dynamics simulations were used to explore the microscopic mechanism underlying the effect of the crosslinked structure of the composites on their properties. The NBR/PA66/GO composite exhibited the best 1S properties. However, when the sulfur content was higher, excessive cross-linking occurred, and the sulfide cross-linking network structure inside the matrix was damaged. This study also provides a viable strategy for the preparation of vulcanized rubber-plastic blend composites with potential for a wide range of industrial applications.