Hydrogenated styrene–isoprene–butadiene rubber: optimisation of hydrogenation conditions and performance evaluation as viscosity index improver

Abstract

AbstractHydrogenated styrene–isoprene–butadiene rubber (HSIBR) was prepared through the hydrogenation reaction of self‐prepared styrene–isoprene–butadiene rubber using a Ziegler–Natta type catalyst prepared with nickel naphthenate (Ni) and aluminum triisobutyl (Al). The precursors and corresponding hydrogenated polymers were characterised using size exclusion chromatography, proton nuclear magnetic resonance (1H NMR) spectroscopy, differential scanning calorimetry and thermal gravimetric analysis. The effects of various reaction parameters on the level of hydrogenation, calculated from 1H NMR spectroscopy, were investigated in the current paper. A maximum of 98% hydrogenation was obtained under the following conditions: Al/Ni molar ratio, 6; catalyst amount, 3 mg Ni per g of polymer; time, 3 h; temperature, 60°C; H2 pressure, 4 MPa and polymer concentration, 10 wt.%. Moreover, a different SAE 5W‐30 multigrade oil (5 CST hydroisomerisation dewax base oil) was formulated using HSIBR samples as viscosity index improvers (VII). The effect of butadiene/isoprene mass ratio in HSIBR on the performance of VII for lubricants was investigated here for the first time. HSIBR used as VII for lubricants integrated some advantages of hydrogenated styrene–butadiene rubber and hydrogenated styrene–isoprene rubber. Copyright © 2014 John Wiley & Sons, Ltd.