VULCANIZATION SYSTEMS FOR RUBBER COMPOUNDS BASED ON IIR AND HALOGENATED IIR: AN OVERVIEW

ABSTRACT The properties of IIR and halogenated IIRs, such as excellent steam and gas impermeability, heat aging stability, and oxygen and ozone resistance and increased chemical resistance, meet the demands of various industrial applications. However, due to the low level of unsaturation of IIR, the vulcanization rate is rather low and the degree of cross-linking is usually insufficient, causing IIR to be minimally co-vulcanized with unsaturated general-purpose rubbers. The low reactivity of IIR requires the consideration of a special composition of curing systems to provide the best possible rate and state of vulcanization. The type of curing system selected must also be a function of the composition of rubber formulations in which the IIR is used, and with respect to the final product's performance requirements. Therefore, the curing systems for IIR differ and can include standard sulfur systems, phenol-formaldehyde resins, or quinones. The incorporation of halogen (chlorine or bromine) atoms into the structure of IIR significantly increases the chemical reactivity, which can be subsequently reflected in a higher curing rate and the possibility to use some additional vulcanization systems such as metal oxides, diamines, or peroxide with co-agent. This study reviews the types and selection of applicable curing systems for IIR and its halogenated derivates.