| The use of lubricant additives can improve the tribological properties of basic lubricants to a certain extent,which has reached a broad consensus in scientific research and engineering applications.With the continuously deepening the research,polymer-based lubricating additives have shown excellent lubricating properties.Moreover,from atomic,molecular,and supramolecular levels,polymer additives with coordination groups have more advantages than small molecules: there are more coordination sites with the surface of friction pair,the corresponding self-assembled film is thicker,and the viscosity of the lubricating oil solution is greater,and it is adjustable.However,at this stage,there are still very few research cases of anti-friction and anti-wear lubricant additives based on polymers,and there is a lack of operational guidance mechanisms for the design and synthesis of such polymer lubricant additives.Based on the above background,this dissertation has explored a series of novel polymer lubricant additives for friction and wear reduction as follows:First,a series of polymer-based lubricant additives with long carbon chain structure were synthesized,and their tribological properties in PAO-10 base oil were tested,and the influence of different functional groups in the side chain on the overall lubrication effect of the lubricant was compared.During the entire test time,the lubrication effect of all lubricants with polymer-based additives was significantly improved compared to PAO-10 base oil,and polymer additives with double-bond carbon structure in the side chain showed better lubrication properties than polymer additives with pure alkyl chains,and the polymer of BE-OAm showed the best lubrication performance.At a concentration of 15 mg/m L,the wear volume of the steel surface lubricated by BE-OAm was reduced by 98% compared to that of PAO-10.From the analysis of X-ray photoelectronic spectroscopy(XPS)and scanning electron microscopy(SEM),it can be seen that the excellent lubrication effect is due to the adsorption of the polymers on the wear surface,which hinders the direct contact of the friction pair.Based on the research results of the first work,the third chapter of this dissertation selects the less studied Zr-MOFs materials and adds them to the polymer additives that have been reported to have good lubricating properties.We want to know whether the Zr-MOFs materials can further improve the lubricating properties of the polymer additives in base oils,and compares the lubricating properties of the two Zr-MOFs materials of Ui O-66(Zr)and MOF-808(Zr).The lubricating properties of polymer/Zr-MOFs composite materials,are better than those of the polymer additives alone.The results showed that the polymer additive added with Zr-MOFs material has lower wear volume in the friction pair under the suitable concentration conditions.This is due to the high mechanical strength of the Zr-MOF nanomaterials,which play a role similar to “rolling bearings”,greatly reducing the direct contact between the friction pairs.Accordingly,the friction process changes from sliding to rolling,which has the effect to reduce friction and wear. |
