Task-Specific Ionic Liquids with Lactate Anion Applied to Improve ZnO Dispersibility in the Ethylene-Propylene-Diene Elastomer

Task-specific ionic liquids (TSILs) are ionic liquids with structures and, consequently, properties and behaviors designed for particular applications. In this work, task-specific ILs with alkylammonium or benzalkonium cations and carboxyl groups in the form of lactate anions were used to promote the homogeneous dispersion of the curatives in the elastomer matrix. The reaction of carboxyl groups of TSILs with zinc oxide, which acts as a vulcanization activator, was confirmed. This interaction improved the solubility and dispersibility of zinc oxide particles in the ethylene-propylene-diene (EPDM) monomer matrix, which consequently affected the curing characteristics of rubber compounds. Most importantly, TSILs increased the efficiency of vulcanization by shortening the time, lowering the temperature and increasing the enthalpy of this process, while maintaining safe processing of elastomer composites. EPDM vulcanizates containing TSILs with lactate anion were characterized by satisfactory functional properties.