Study On Tribology Of Hydroxy And Sulfurized Vegetabale Oil Fatty Acids

Two types of lubricating oil additives which are hydroxy vegetable oil fatty acids without active elementes and sulphurized fatty acids with active elements sulphur were developed in this thesis, in which, hydroxy vegetable oil fatty acids are "green" lubricants without contamination, so they have significance for environmental protection. Chemical structure characterization of these additives synthesized were carried out by infrared spectrometry, elementary analysis, thermogravimettic analysis and capillary melting poinp test, triobological characteristics of those additives in liguid paraffin were studied, and rubbing surfaces of oils containing these addtives were analyzed by X-ray Photoelectron Spectroscopy and Refection Micro Fourier Transform Infrared Spectroscopy, respectively. Base on these results, each lubrication mechanism of two types of additives were put forward, thus we point out that green lubricants may be synthesized using vegetable oils, main research results of this thesis are as follows:1. Oxygen plays critical roles in lubrication mechanism. Oxygen affects the lubrication mechanism of additives all along, whether in sulfurized vegetable oil fatty acids containing active element or not in hydroxy vegetable ,oil fatty acids with pure carbon, hydrogen and oxygen not containing active element.2. Hydroxy vegetable oil fatty acids are a kind of potential antiwear and extreme pressure(EP)agents. The antiwear and EP properties of 13,14-dihydroxydocosanoic acid are approched to Zinc dialkyldithiophosphates (ZDDP), so it will replace ZDDP. Because preparation process is green chemical synthesis without contaminationand raw materials come from clean and rich vegetable oils, it is competely green lubricants.3. The lubrication mechanism of hydroxy vegetable oil fatty acids is that the friction polyester film is formed on rubbing surfaces by intermolecular esterification of hydroxy fatty acids, and friction and wear of metal pairs was decreased sharply during to the presence of this film.4. The strength and steroconfiguration of polyester film were analyzed by Infrared Spectroscopy theory based on the wave numberdisplacement of characteristic absorption peak vasc_0c of the ester formed. Internal relations between antiwear order law of hydroxy fatty acids and vibration absorption peak vf_0c of polyester formedby hydroxy fatty acids was deduced by quantum mechanics and classical mechanics,and the antiwear order of hydroxy fatty acids was reasonably explained, that is 13,14-dihydroxydocosanoic acid>13(14)-monohydroxydocosanoic acid=9,10-dihydroxyoctadecanoic acid >9,10,12-trihydroxyoctadecanoic acid > 9(10)-monohydroxyoctadecanoic acid. A net-like polyester film is formed by 13,14-dihydroxydocosanoic acid and a linear polyester film is formed by 9,(10)-monohydroxyoctadecanoic acid and 13(14)-monohydroxydocosanoic acid.5. The application of cold vulcanization technology was developed, non-odour sulphurized vegetable oil fatty acids were prepared by low temperature vulcanization and metathetical reaction.6. The antiwear properties of hydroxy vegetable oil fatty acids are better than that ot sulphurized vegetable oil fatty acids , whereas the extreme pressure property is reciprocal,EP property of dihydroxy-docosanoic acid is very near to that of sulfurized olefin(SO) without oxygen group, in liquid paraffin base stocks, maximum non scuffing load PB of the former is 539N, PB of the latter is 588N. It is seen thatoxygen group function of additives is very remarkably in tribological characteristics, that is EP property of dihydroxydocosanoic acid without active element is very near to that of SO with active element sulfur.7. The antiwear rule of sulphurized vegetable oil fatty acid is, sulphurized octadecanoic acid > sulphurized docosanoic acid, and EP rule is exactly reciprocal, whereas the antiwear and EP properties of sulphurized vegetable oil fatty acid are better than that of SO without oxygen group, it was found that oxygen group function is also very import...