Effect of sulfur donor and co-agent as scorch delay system over third monomer EPDM-ENB content

Abstract

The third monomer is an important characteristic of EPDM rubber, as it directly influences the mechanical and thermal properties of the material. Peroxide vulcanization is often used as a curing system. Furthermore, it increases lifetime and offers dynamic mechanical properties and scorch time lower than sulfur systems. Here, we report the influence of dipentamethylene thiuram tetrasulfide and HVA-2 (N,N-m-phenylene bismaleimide) on peroxide vulcanization at different ENB content on EPDM rubber to reach an ideal condition for the reduction of vulcanization scorch time and improve the its mechanical properties. Tensile strength was highly affected by SDS formulation, increasing to 10 MPa for ENB1.8% and 15 MPa for ENB4.9% and ENB8.5%. Moreover, elongation at break increased from 398 to 650% for ENB1.8%, from 260 to 433% for ENB4.9% and from 290 to 408% for ENB8.5%. Compression set of SDS system was also increased when different ENB contents were compared for a conventional vulcanization system. Tear strength of ENB4.9% and 8.5% enhanced from 25 to around 32 N/mm with the scorch delay system. These results are important for the improvement of gaskets of plate heat exchanger production.