| Friction and wear are inseparable from human life.All mechanical systems in motion suffer from mechanical failures and equipment aging caused by friction and wear resulting in serious environmental pollution and waste of resources.Among them,wear and corrosion of metallic materials are very prominent,which greatly reduces their long-term service life in the engineering field.Therefore,there is an urgent need to develop high performance composites with high strength and wear resistance.Epoxy resins（EP）have been widely used in automotive,aircraft,railroad transportation systems and electrical and electronic fields due to their light weight,high mechanical strength,low curing shrinkage,and excellent chemical stability and electrical insulation properties.However,the high cross-linkage of EP makes its fracture energy low,wear resistance poor and service life short,which obviously limits its application in harsh friction conditions.In order to maximize the engineering applications of EP,improving its tribological properties has become a common concern for researchers and industry personnel.Based on this,the main thesis is as follows:（1）Based on a brief overview of the definition,applications and toughening of epoxy resins,the current status of research on the wear mechanism of polymers and tribological properties of two-dimensional materials is summarized.（2）Used the concept of interfacial interpenetration to enhance the interfacial interaction of epoxy/rubber composites,the interfacial interaction between EP and carboxyl terminated butadiene acrylonitrile（CTBN）was enhanced by the free radicals generated by the initiator diisopropylbenzene peroxide（DCP）to promote the opening of double bonds in the molecular chains of liquid rubber,which in turn undergoes crosslinking under sulfur-free conditions.Then,the effects of DCP and CTBN dosage on the mechanical and tribological properties of EP were investigated.FTIR,DSC,SEM,EDS,XPS,and Raman were used to characterize the structure of epoxy resin/carboxyl terminated butadiene acrylonitrile（EP/CTBN）composites and their worn surfaces,and the effect of CTBN on the wear mechanism of EP was thoroughly investigated.The results showed that the best overall mechanical（in which the flexural strength and modulus were 118.7 MPa and 3446.2 MPa,respectively）and tribological(friction coefficient and wear rate were 0.64 and 4.1×10-5 mm3/Nm,respectively)properties were obtained when the DCP dosage was 1%and the CTBN dosage was 15 phr for subsequent experiments.（3）The SiO2@MoS2 core-shell structure was successfully prepared by a one-step hydrothermal method,which was then employed for further modification of EP/CTBN15.The friction and wear properties of the studied composites were tested in Ring-on-Plate configuration under different loads and velocities.In order to reveal the tribological contribution of MoS2 and SiO2 in the composites,tribological tests were also performed on a single MoS2 and SiO2 filled EP.The SiO2@MoS2 core-shell structure and the worn surface of their composites were analyzed by SEM,EDS,XRD,BET and XPS.The results show that the migration of EP/CTBN15 matrix and SiO2@MoS2 core-shell filler plays an important role in controlling the tribological properties of rubber-toughened EP composites.Depending on the contact conditions,SiO2@MoS2 core-shell structure fillers may be released into the sliding interface and undergo tribochemical reactions,all of which contribute to improving the tribological properties of the composites under study.（4）MXene and carbon fiber hybrid fillers（MX@CF）was successfully prepared by electrostatic adsorption and incorporated into the best performing EP/CTBN15composites screened in the second part.The tribological properties of EP-based composites were studied by adding MXene,carbon fiber and MX@CF hybrid fillers separately,and the effects of different PV values on the tribological properties of polymer composites were also investigated.SEM,EDS,XPS and Raman were used to elucidate in depth the friction reduction and anti-wear mechanisms of MXene and carbon fiber on polymers and their composites.The results showed that the friction coefficient and wear rate of the composites were reduced to 0.34 and 0.24×10-5mm3/Nm,respectively,after the addition of MX@CF-2 hybrid filler to the EP/CTBN15composites,which were 55.8%and 96.6%lower compared to those of the EP/CTBN15composites.This excellent wear resistance is attributed to the synergistic action between the rubber and the two fillers.In summary,this thesis has improved the tribological properties of epoxy resins through the synergistic effect of CTBN and two-dimensional fillers with other fillers,and explored the law of the influence of rubber and fillers on the tribological properties of polymers.This lays a theoretical foundation for the design and preparation of polymer composites requiring long service life under harsh working conditions. |
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