Terpolymers for modifying the performance properties of engine oil

Nine terpolymers consisting of (jojoba: alkylacrylate: α-olefins) backbone were synthesized via free radical chain addition polymerization and determined using Fourier transform infrared spectroscopy, proton nuclear magnetic resonance and gel permeation chromatography, for determination of weight average molecular weight. The alkylacrylates used were (dodecylacrylate, tetradecylacrylate and hexadecylacrylate), while α-olefins used were (dodecene, tetradecene and hexadecane). The monomers’ ratio used for polymerization was (1:1:1). It was found that the molecular weight increases with increasing the alkyl chain length of both alkylacrylate and α-olefins used. The thermal stability of the synthesized terpolymers was determined using thermal gravimetric analysis and differential scanning calorimetry. The prepared polymers were evaluated as performance modifiers (viscosity index improvers and pour point depressants) for free additives lube oil (SAE-30). It was found that the viscosity index increases with increasing the alkyl chain length, molecular weight and concentration of used terpolymer. The effect of the prepared terpolymers on the pour point of lube oil was studied and it was found that the pour point of lube decreases (more negative) with decreasing the alkyl chain length of both alkylacrylate and α-olefin used.