A Research On New Preparation Technology And Application Of High Anti-friction And Anti-wear Vehicle Dynamic Seal

In recent years, with the rapid development of automobile industry, higher requirementwere put forward to vehicle dynamic seal, not only to the necessary mechanical propertiesand oil resistance, but also to maximize the wear resistance. Nitrile butadiene rubber （NBR） isa kind of oil resistant rubber, widely used for vehicle dynamic seal. Solid lubricant often beadded to NBR, in order to reduce friction coefficient of NBR products to improve the wearresistance. Molybdenum disulfide （MoS₂） and graphite are hexagonal system of layeredstructure, has special chemical properties and self lubrication, which can play the roleof reducing friction. Howener, reunite, uneven dispersion will happen because of poorinterface compatibility between molybdenum disulfide, graphite and rubber matrix, whichinfluencing the mechanical properties of composite. At present, lots of research is onpreparing composite use only molybdenum disulfide or graphite. The innovation of this workis surface modifing and blending the molybdenum disulfide, graphite to find out the bestformula design.First, cetyl trimetyl ammonium bromide （CTAB）, silane coupling agent （KH570） andpolyethylene glycol （PEG） were used to modify the surface property of molybdenum disulfideand graphite. Then, MoS₂/NBR composites, graphite/NBR composites and graphite/MoS₂/NBR composites were prepared by directly mechanical blending. Meanwhile, the effects ofloading content of MoS₂and graphite, the kinds of modifiers on the the mechanical andtribological properties of the composites were evaluated. The dispersion of fillers in rubbermatrix and the worn surface of the composites were analyzed by SEM.Results showed that:（1） Mechanical and tribological properties of NBR that addingMoS₂and graphite （MoS₂more than graphite） were superior to which aading MoS₂or graphite.（2） The dispersion of fillers in rubber matrix and mechanical properties of NBRfilled with modified MoS₂or graphite were better than which filled with unmodified MoS₂orgraphite, furthermore, KH570is more conducive to modify graphite than CTAB and PEG,While CTAB is more beneficial to modify MoS₂than the other modifiers.（3） When add10phrCTAB modified MoS₂in rubber matrix, the friction coefficient of composites was0.8, whileadd20phr KH570modified graphite in rubber matrix, the friction coefficient of compositeswas0.7, the lowest friction coefficient （0.5） was obtained when adding3phr KH570modifiedgraphite and7phr KH570modified MoS₂in rubber matrix.（4） The dispersion of fillers inrubber matrix were better and the worn surface of the composites were more smooth and flatwhen the composites have better mechanical or tribological properties.