Tribological Behavior of Aqueous Copolymer Lubricant in Mixed Lubrication Regime
TD Ta and AK Tieu and HT Zhu and Q Zhu and PB Kosasih and J Zhang and GY Deng, ACS APPLIED MATERIALS & INTERFACES, 8, 5641-5652 (2016).
Although a number of experiments have been attempted to investigate the lubrication of aqueous copolymer lubricant, which is applied widely in metalworking operations, a comprehensive theoretical investigation at atomistic level is still lacking. This study addresses the influence of loading pressure and copolymer concentration on the Structural properties and tribological performance of aqueous copolymer solution of poly(propylene oxide)-poly ( ethylene oxide)-poly(propylene oxide) (PPO- PEO-PPO) at mixed lubrication using a molecular. dynamic (MD) simulation. An effective interfacial potential, which has been derived from density functional theory (DFT) calculations, was employed for the interactions between the fluid's molecules and iron surface. The simulation results have indicated that the triblock copolymer is physisorption on iron surface. Under confinement by iron surfaces, the copolymer molecules form lamellar structure in aqueous solution and behave differently. from its bulk State. The lubrication performance of aqueous copolymer lubricant increases with concentration, but the friction reduction is insignificant at high loading pressure. Additionally, I. the plastic deformation of asperity is dependent on both copolymer concentration and loading pressure, and the wear behavior shows:a linear dependence of friction force oh the number of transferred atoms between contacting asperities.
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