Research On Water-based Lubricating Properties Of Polyvinylpyrrolidone

Traditional lubricants are widely used in modern industries,but they are harmful to the environment.In the view of environmental protection and sustainable development,it is of great significance to develop environmentally friendly lubricants with excellent performance.Water-based lubrication is a kind of lubrication method by adding different kinds of lubricating additives to pure water to improve its friction reduction performance.It possesses excellent friction reduction and lubricating effect in the environmentally friendly manner,which makes it show important application value.In this paper,polymer polyvinylpyrrolidone(PVP)was used as a water-based lubricant additive to study the lubrication characteristics of the solution.The main research contents include as followed.The FTMR spectrum of PVP molecule was measured.It was found that PVP molecule is a water-soluble polymer with hydrophilic group and polar group.The interaction between PVP molecule and water molecule was simulated by material analysis software.PVP molecules can form a solid hydrogen bond network with water molecules which result in the lubricating effect.Quartz glass was used as friction pair to study the effect of PVP solution concentration,load and rotational speed on the lubrication effect in the condition of surface contact.When the concentration of PVP solution is 3.00wt.%,the lubrication performance is the best.The increase or decrease of concentration will increase the friction coefficient.The load significantly affects the lubrication characteristics of PVP solution.When the load is 5 N,the friction coefficient is the smallest.The change of the speed under different loads has different effects on the lubrication performance of the solution.When the load is 3 N and 5 N,the friction coefficient hardly changes with the rotational speed.When the load is 7 N and 9 N,the friction coefficient is different at different speeds.The effect of PVP solution concentration and rotational speed on the lubrication effect was studied by using Si3N4/Ti6Al4V as friction pair in the condition of point contact.The lubrication effect is best when the solution concentration is 5.00wt.%.The effect of the rotational speed on the lubrication effect is different under different loads.When the load is 0.3 N,as the rotational speed increases,the friction coefficient does not change significantly.The friction coefficient decreases with the rotational speed increasing when the load is 0.5 N.However,the solution lubrication failure is likely to occur after the rotational speed is greater than 210 r/min.The friction coefficient increases slightly.The effects of running-in process on the lubricating properties of PVP solution were studied with the friction pair of Si3N4/Ti6A14V.The effects of dry friction running-in process and boric acid running-in process on solution lubrication characteristics were analyzed.The results indicate that dry friction running-in process can improve the lubrication effect of the solution,but could not maintain the long-term stability of lubrication.Appropriate running-in speed and solution concentrations help to reduce the friction coefficient.Boric acid running-in process plays an important role in maintaining the stability of the lubrication process.But the reduction of friction coefficient is small.Appropriate solution concentration can get an excellent lubrication after boric acid running-in prdcess.