Production and characterization of magnetic EPDM composites with carbonyl iron powder (CIP) using different curing systems

Magnetic composites were manufactured by incorporating 5 phr of Carbonyl Iron Powder (CIP) and 60 phr of carbon black into ethylene propylene diene monomer (EPDM). This study aimed to examine the impact of different curing systems - sulfur and accelerators, peroxide, and peroxide with co-agents - on the cross-linking of the EPDM matrix while keeping other additives constant. Seven composites were produced and characterized in terms of morphology, cross-link density, rheometric, mechanical, and magnetic properties. The sulfur curing system reduced curing time and increased cross-link density, resulting in higher rigidity. The peroxide-based system, when combined with co-agents, provided optimal performance in elongation and tear strength, with tensile strength values similar to the sulfur system. Cross-link density was highest for the sulfur and accelerator systems, and the Gibbs free energy was higher due to reduced molecular mobility in highly cross-linked networks. The 5 phr CIP content did not affect the physical-mechanical properties. Scanning Electron Microscopy (SEM) revealed minimal interaction between EPDM and CIP, and magnetic analysis showed that the curing system had no significant impact on the magnetic properties of the composites.