| Thermosetting resin has good thermal stability,is due to the irreversible cross-linking reaction,which heats or reacts with the curing agent cross-linked into insoluble and non-fusible network products.Epoxy resin and phenolic resin as the two most typical thermosetting resins,widely used in paints,adhesives.Phenolic resin on account of its high heat resistance,good mechanical strength,flame retardant and good processing performance is widely used in friction materials binder.In order to overcome poor wear resistance of pure epoxy resin,the core-shell structure(Si O2@GO)formed by electrostatic self-assembly of nano-Si O2 and graphene oxide(GO)was used to modify the epoxy resin.The friction and wear properties of epoxy resin and its nanocomposites were investigated by LSR-2M high-speed reciprocating friction and wear tester under the conditions of dry friction,and the mechanism of friction and wear was discussed.The results show that the mechanical properties and tribology properties of the nanocomposites are improved by the core-shell structure Si O2@ GO.When the content of Si O2@GO is 0.5 wt%,the mechanical properties of the composites are the best,and the wear rate and friction coefficient are the lowest,and the wear resistance is good.Compared with the same content of nano-filler Si O2 and Si O2-NH2 which modified with silane coupling agent,the mechanical properties and tribology properties of the nanocomposites were improved,but the reinforcing effect was Si O2@GO> Si O2-NH2> Si O2.Friction material is a kind of multi-component composite material,which is made up of three main components of binder,reinforcing filler and friction modifier,and other compounding agent.The main constituent is fiber,mineral filler,anti-friction material andfriction material.As the main component,binder constitute the core of the friction material,the amount of binder material is usually accounted for 8 to 25%.Many kinds of modified phenolic resin(PF)-based friction material is the earliest and the largest amount used,which is due to the unsatisfactory performance of pure phenolic resin(2123 resin)in practical application.In this study,nitrile rubber modified phenolic resin used as a binder for the friction material.The reinforcement consists of(1D)fibers,(2D)sheets,micro-nano materials.The multifaceted,multidimensional,and multidimensional composite reinforcement systems have significant effects on the strength of the friction material.While a single enhancement method is difficult to meet the temperature,pressure,friction speed,the impact of friction coefficient stability,good wear resistance and a certain mechanical strength and physical properties of the comprehensive technical requirements.Thus,the multi-dimensionalcomposite enhancement system can achieve the multi-element composite enhancement system with certain comprehensive performance through its complementary advantages and synergistic effects.Some two-dimensional sheet materials on account of its low shear strength and low hardness are widely used in friction materials in anti-friction materials or lubricants,such as graphite,molybdenum disulfide,mica and so on.a-zirconium phosphate(?-Zr P)is a typical two-dimensional cationic layer compound,because of its size controllable,high thermo-chemical stability,high surface energy,high ion-exchange,easy stripping,and surface functional groups can be designed and tailored,which was used in lubricant research.In thisstudy,the different interlayer spacing of zirconium phosphate and Si O2-GO-Zr(AE)3P(SZG)reinforcing hybrid filler,which is composed of zirconium organophosphate(OZr P),graphene oxide(GO)and silica(Si O2)are used in the phenolic resin-based friction materials to study the friction and wear properties.Research indicates:(1)The zirconium phosphate at different interlayer spacing include ?-zirconium phosphate and its polyether amine intercalation derivatives(polyether amine D230 / ?-Zr P,polyether amine D400 / ?-Zr P),which the friction and wear properties of phenolic resin based friction materials were improved.When the content of ?-Zr P is 1 wt%,the friction coefficient of ?-Zr P / PF friction material is the largest and stable,and the wear amount is also corresponding minimum under the condition of dry friction at room temperature,that is,it has good wear resistance.The results showed that the addition of polyether amine D230 / ?-Zr P and polyether amine D400 / ?-Zr Pmodified with polyether amine intercalated on the phenolic resin-base friction materials,with the different interlayer spacing,the different degree of the adjust to friction coefficient of the friction materials.(2)Compared with the single two-dimensional sheet reinforcement,the reinforcement of Si O2-GO-Zr(AE)3P(SZG)has better friction stability,wear resistance and thermal stability,which is due to its synergy between several materials.Modified spherical silica can improve the thermal degradation and recovery properties of composites,but also improve the wear resistance of composites.The tribological properties of the composites were also improved by the addition of zirconium triethylenetriamine phosphonate as the reinforcing material.The graphene oxide(GO)serves as both bridging bridge between silica and organophosphate,also used as an anti-friction material to modulate the friction coefficient of the materials as well as to reduce wear.Therefore,the reinforcements of Si O2-GO-Zr(AE)3P(SZG)composed of zero-dimensional spherical materials and two-dimensional lamellar materials can effectively improve the friction and wear properties of phenolic resin-based friction materials.When the content of SZG is 5 wt%,the wear rate of the friction material is about 55% lower than that of the blank phenolic resin-based friction material,and the hot fade phenomenon was improved obviously. |
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