Design and development of an affordable and suitable rubber compounding for high altitude application up to −40 °C

Abstract

The highest peak ever scaled by humans is Mount Everest at 8849 m. There is a constant decrease in pressure and a decrease in ambient temperature as one advance above sea level. Indian sub-continent has many places above 1500 m of spiritual importance. Variegated age group scale points of spiritual significance from children to the elderly. At such altitude there is a concern in breathing. Finding a hand-held portable breathing solution is therefore called for. This paper attempts to find an economical rubber-based polymer to be used as a material for a personal high-altitude lifesaving system up to −40 deg Celsius. Mechanical properties of different grades of rubber material with suitable fillers were investigated. Natural rubber with additives was compared with other rubber-based composites. The test samples were exposed to cryogenic conditions (-196 deg Celsius) by immersing in liquid Nitrogen for an appreciable time and were re-tested to exonerate the mechanical properties. Off all the tested samples, the best stiffness was exhibited by Butyl-Nitrile, which is 90% more than natural rubber. Similarly, after dipping in liquid Nitrogen, re-testing results confirm that the Butyl-Nitrile sample shows 95% higher stiffness than natural rubber. After being exposed to cryogenic conditions, the measured stiffness of samples is noted as more elevated than in normal conditions, attributed to its cross-linking properties. The cross-link bond of the butyl and nitrile rubber inhibits the motion inside it to increase the stiffness of the sample. The flow properties of samples were tested through a Mooney rheometer. The flow properties in cryogenic conditions were lower than in normal conditions. The article also delineates a design of the proposed breath assistance device and a wearable jacket.