Influence of molecular and crosslink network structure on vulcanizate properties of EPDM elastomers

Abstract

In elastomer science and technology, the advent of vulcanization led to a paradigm change. Despite ongoing research, vulcanization science and technology have a great deal of untapped potential. This article explores how the various vulcanization systems, such as sulfur-based, peroxide-based, and their hybrid systems, would reflect changes in the physiomechanical characteristics of ethylene-propylene-diene monomer (EPDM) rubber with various molecular configurations. This kind of analysis illuminates the characteristics of the crosslinking network established by each vulcanizing technology. Since solid viscoelastic rubbers include a large number of components, it is nearly impossible to evaluate the crosslinking network directly. If all components other than vulcanizing systems remained intact, stress relaxation behavior correlated directly with the crosslinking network inside the samples. In this work, temperature scanning stress relaxation (TSSR), a relatively new technique capable of creating the whole spectrum of stress relaxation, was effectively explored. The findings suggest that sulfur and carbon crosslinks coexist in hybrid systems regardless of the molecular structure of the elastomer, and their synergistic impact is evident. Furthermore, it is clear from the results that the molecular structure of the vulcanizates has an impact on the final properties, such as tensile, compression strength properties and thermal properties of the samples.

Keywords

• hybrid crosslinking network
• tssr
• mechanical properties
• rubber
• polymer composites