Chemical recycling of sulfur-cured natural rubber using supercritical carbon dioxide

Abstract

Sulfur-cured unfilled natural rubber (NR) was devulcanized in supercritical CO₂ (scCO₂) by using diphenyl disulfide (DD) as a devulcanizing reagent. The product was fractionated into sol and gel components. The fraction of sol component that contains reusable linear polymer increased with the increase in CO₂ pressure, especially over the critical pressure. The molar mass of the resulting sol component was about tens of thousands and the crosslink density of the gel component decreased from the initial one.