Tribological Properties Of Propylene Glycol EO/PO Block Polyether Aqueous Solution

As global temperatures continue to rise and extreme climates occur frequently,people's awareness of environmental protection has gradually increased.Therefore,industrial energy saving and emission reduction has become an important direction for future development.Existing oil-based lubricating fluids are facing resource shortages and environmental pollution problems,so the demand for water-based lubricating fluids is increasing.The tribological properties of propylene glycol EO/PO block polyether aqueous solution were studied,and the two lubricating additives L35 and L45 with the same ratio of EO and PO and different molecular weights were mainly analyzed.In view of the lack of anti-wear and extreme pressure properties of L35 lubricant,triethanolamine oleic soap(TOS)was added to form a compound solution,and the mechanism of the related performance was analyzed.(1)The anti-friction,anti-wear and extreme pressure properties of several lubricating fluids were tested by a four-ball testing machine.The block polyether L35 solution has excellent anti-friction performance at high concentration.The friction coefficient at 15% concentration is as small as 0.019,which significantly improves the anti-friction performance of pure water.In contrast,L45 has better antiwear properties,and the average wear scar diameter is less than that of L35 solution.After adding TOS to the block polyether L35,the anti-wear performance is very outstanding.At 15% concentration,the wear spot diameter is reduced by 35%.Since the compounded solution contains N element,the extreme pressure value of the 15% concentration solution is increased to 10 times that of the pure L35 solution.(2)The three-dimensional optical profilometer was used to collect the data of the center section curve of the steel ball wear scar after the friction and wear test,and the second-order polynomial fitting analysis was performed.It was found that the R-squared value of the steel ball curve fitting after L35 lubrication at 5% concentration was as high as 0.99,which was higher than that of L45 solution at the same concentration.After adding TOS to the L35 solution,the surface of the steel ball lubricated by the low concentration solution has fewer furrows and scratches,and the surface is smoother.(3)The wettability of the solution was tested by a contact angle measuring instrument,and it was found that the contact angle of the L45 solution was significantly smaller than that of the L35 solution,and the wettability was better.After adding TOS to the L35 solution,it can also reduce the surface tension of the block polyether L35 solution and improve its wetting performance.When the concentration is 1%,the wetting performance is improved by 19.2%.(4)Using a rotary rheometer to study the rheological properties of several lubricating fluids,it was found that the three solutions of L35,L45 and L35+TOS have obvious Newtonian fluid characteristics at room temperature.When the ratio of block polyether EO/PO is the same,its viscosity value is not much different.The molecular chain length of L45 with a relatively high molecular mass is higher than that of L35,and the degree of molecular entanglement is more intense,which will result in a slightly higher viscosity than L35.The viscosity-temperature coefficient of the mixed solution of L35+TOS has been reduced,and the viscosity-temperature performance of the solution has been improved.Therefore,the three lubricating additives L35,L45 and L35+TOS added to the aqueous solution have a good lubricating effect,can be selected for different use conditions and requirements,and are expected to become a new type of water-based lubricating fluid with good tribological properties.