Synthesis of vulcanizing agent from cardanol

Abstract

Cardanol polysulfide (CPS), a sulfur donor type vulcanizing agent, was synthesized from a reaction of elemental sulfur and cardanol separated from decarboxylated cashew nut shell liquid. The appropriate conditions for the preparation of CPS using an elemental sulfur without any solvent at 140 ℃ for 3 hrs giving 28% wt of sulfur content in CPS. The effect of CPS as vulcanizing agent on the properties of rubber compounds was investigated. It was found that the optimum cure time of rubber containing CPS was reduced and mechanical properties were improved. Accelerated aging test was investigated and the results were compared to unaged specimens. The rubber containing CPS was found to have lower reversion. This work showed that CPS improved basic mechanical properties and reduced the reversion of rubber compounds.