The impact of imidazolium ionic liquids on the properties of nitrile rubber composites

The purpose of this work was to investigate the influence of hydrophilic imidazolium ionic liquids on the curing kinetics, mechanical, morphological, thermal and conductive properties of acrylonitrile–butadiene rubber (NBR) composites. NBR/SiO2/IL composites were prepared by the conventional melt mixing method. It was found that 1-ethyl-3-methylimidazolium thiocyanate (EMImSCN) and 1-methyl-3-octylimidazolium chloride (OMImCl) improved the ionic conductivity of NBR composites. Moreover, both ionic liquids strongly influenced the rheometric data and mechanical properties (static and dynamic). NBR – based composites displayed elastomeric properties and high tensile strength up to 19 MPa when 10 phr EMImSCN was added. The presence of 30 phr EMImSCN in the composite resulted in an increase in its conductivity from 10−11 S/cm (NBR/SiO2) up to approximately 10−5 S/cm (NBR/SiO2/EMImSCN30) at room temperature. Thermal analysis showed that the Tg of NBR/SiO2/IL systems, decreased as a function of increasing ionic liquid content due to a plasticizing effect, particularly for samples containing OMImCl.