Oxygen Into The Extreme Pressure Properties Of The Vulcanization Of Isobutylene

The synergistic effect of sulfur and oxygen on the extreme pressure properties of sulfurized isobutylene(SJB) has been irivestigated.Two ways of addition of oxygen into SIB have been adopted, which are oxidization of SIB and the physical composition of SIB and sulfurized ester. The performance of the oxidized product of SIB has been studied comparatively with those of SIB. InfraRed, '3C Nuclear Magnetic Resonance (13CNMR)and Raman spectrum are applied to find out the EP(extreme pressure )mechanism and give a reasonable explanation for the performance improvement.Sulfoxide and sulfone, which are formed in oxidization of SIB, improve the EP properties and increase the copper corrosion. The oxidization conditions have an important impact on the properties of EP, corrosion and solubility of the additive. Sulfoxide and sulfone,which are polar molecules, enhance the absorption ability of the additive on metal surface, which is the main reason for better EP properties of the oxidized SIB. From the data of the determination of copper corrosion and active sulfur of the additives,it can be found out that sulfoxide and sulfone cause the severe copper corrosion. X-ray electron spectra show that the worn surface layer of steel ball in the Four-ball test formed from oxidized SIB contain FeS, FeSO4 and Fe203.Auger Electron Spectra indicate that in conparision of oxidized SIB and SIB ,the former produces thicker sulfurized layer than the latter in Four-Ball tests.There is better synergistic effect between SIB and sulfurized ester, which show in the improvement of EP properties. However, the copper corrosion increase in the case of use of SIB together with sulfurized easer compared to the use of the single additive alone. The mass ratio between SIB and sulfurized ester is the key faction for the synergistic effect. When the ratios are in the range of 2:1 to 5:1, the synergistic effect is the best. Surface properties are applied to explain the synergistic effect. Sulfurized ester with polar group improves the absorption ability of the additive package on metal surface. X-ray electron spectra show that in the worn surface layer of steel ball in the Four-ball test exist FeS,FeSO4and Fe203. Auger Eleciron Spectra demonstrate that a thicker sulfurized layer is formed form the additive package compared to that from SIB.