A Short Review on Polymeric Biomaterials as Additives for Lubricants

With increasing environmental concerns and the depletion of petroleum resources, the development of lubricant additives from bioresources has attracted much attention recently. In this review, we reported a few polymers and polymer composites that are synthesized from vegetable oils (soybean oil, sunflower oil, rice bran oil, and castor oil) and used as multifunctional additives in the formulation of eco-friendly lubricant compositions. We mentioned the preparation of vegetable oil-based homo- and copolymers and their characterization by different spectral techniques (FTIR/NMR). The average molecular weights of the polymers are determined by gel permeation chromatography (GPC). Performance evaluations of the polymeric materials mainly as a viscosity index improver (VII), pour point depressant (PPD), and most importantly antifriction additives when blended with lubricating base oils are indicated. Standard ASTM methods have been applied to evaluate their performances. The findings have shown that all the additives discussed are non-toxic, biodegradable, and showed excellent performances compared to commercial petroleum-based additives.

Polyacrylate-magnetite nanocomposite as a potential multifunctional additive for lube oil

The application of polymer nanocomposites (PNCs) in lubricant industry has attracted considerable interest due to their much enhanced properties compared to neat polymers. In this study, magnetite (Fe3O4) nanoparticles (NPs) were synthesized. Then PNCs were prepared by reinforcing these NPs in the homopolymer of dodecyl acrylate in different percentages. The characterization of the prepared NPs and PNCs was done by different analytical techniques. Thermal stability is determined through thermogravimetric analysis (TGA). Performance evaluation of the PNCs as viscosity index improver, pour point depressant and antiwear additive was carried out by blending them with a mineral base stock at different percentage ratios. Standard ASTM methods are followed to carry out the evaluations. It is found that with increasing the percentage of nanocomposites in the base stock, the overall performance of the furnished lubricant is enhanced.

Coarse-Grain Simulation of Lubricant Polymer Solutions

Polymer solution is used as lubricant in Tribological applications. Viscosity index improver is used to normalize temperature dependence of viscosity of the lubrication oil. Biological system such as synovial joint is a kind of polymer solution and strongly related to Tribology. Here we show our numerical simulation approach to investigate the dynamics of polymer solution. The numerical scheme is for simulating the dynamics of suspensions of Brownian particles, coupling molecular motion treated by Langevin equation and hydrodynamics treated by lattice Boltzmann method. The motion of polymer segments are simulated under shear condition in bulk, and in confined geometry. The viscosity change due to the change of polymer structure is found both in bulk and in confined geometry. In order to simulate realistic polymers, we modify each polymer segment as polar and non-polar particles. Point dipoles are added on the polar segments. Since the relative permittivity is very different in water and oil condition, the structure of the polymer is strongly affected by the distribution of the polar segments.