| Tribology is a very complicated discipline that studies the influence of friction behavior on the interactive surface of relative motion.Its rapid development benefits from the high demand in actual industrial production.As the mechanical equipment moves towards high power and high speed,a variety of practical conditions also emerge,some of which are very demanding.Under the influence of many unfavorable factors,the problem of mechanical parts loss caused by friction is becoming increasingly prominent,which not only seriously affecting the precision of the instrument,reducing the working efficiency of the equipment,but also greatly shortening its service life,resulting in huge economic losses.Therefore,the urgent problem to be resolved in the process of design,manufacture and use of machinery is how to improve the durability of the equipment,reduce the friction loss,and ensure its normal operation.The extraordinary demand for industrial production also produces more kinds of anti-friction and wear-resistant materials.Polymers have numerous advantages such as low friction coefficient and small wear,combined with their simple production process and low cost,and their contribution to friction reduction and wear resistance is extremely prominent.Polyphenylene sulfone?PPSU?is an amorphous thermoplastic resin with excellent chemical stability and heat resistance,non-toxic and harmless,good fluidity in the molten state,easy molding,and has been widely used in many fields.However,in terms of friction and wear properties,the friction coefficient and wear rate of pure PPSU are very high,which cannot meet the practical application standard and cannot be used as a single wear-resistant material.Therefore,it is an important practical and economical research work to improve its friction and wear performance and expand its application range.Adding lubricating materials to PPSU is a modification method with high feasibility and low cost.In this paper,PPSU was used as the matrix of the blend resin,two different types of lubricating materials,the inorganic compound graphite and the metal compound molybdenum disulfide,were selected as solid lubricants.Based on the good fluidity of PPSU in melt state,a series of resin matrix composites were prepared by melt-blending by extrusion and injection molding.The effects of the factors on the friction and wear properties of PPSU were analyzed by changing the mass fraction of solid lubricant,particle size,and the load and rotational speed of the sample during the friction process using friction testing machine and scanning electron microscope?SEM?.At the same time,thermal properties,mechanical properties,and fluidity of PPSU blends were characterized by a series of test methods,such as thermogravimetry?TGA?,heat deflection temperature?HDT?,dynamic mechanical analysis?DMA?,electronic universal testing machine,and capillary rheology.The effects of friction and wear modification and other properties of the blends were analyzed and discussed comprehensively.The results show that graphite and molybdenum disulfide can significantly reduce the friction coefficient of polyphenylene sulfone,and the decrease range reaches 62%and 56%,respectively.At the same time,the thermal and mechanical properties of polyphenylene sulfone have been improved to varying degrees.After the solid lubricant was added,the wear debris of the surface of the polyphenylene sulfone was reduced and the abrasive wear occupied the dominant position.The friction coefficient of polyphenylene sulfone can be greatly reduced regardless of the particle size of the solid lubricant added,and the friction coefficient of the 8000 mesh GC/PPSU and 15000mesh MoS2/PPSU blends were the smallest.Under the same conditions,the anti-friction effect of adding graphite alone is better than adding molybdenum disulfide separately.The polyphenylene sulphone modified with graphite and molybdenum disulfide has obvious friction synergistic effect,which can significantly reduce the wear rate of polyphenylene sulphone. |
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