Liquid Exfoliation Of Molybdenum Disulfide And Its Influence On The Performance Of Rubber Wear Resistance

Molybdenum disulfide (MoS2) has a very special layered structure. When subjected to external forces, the weak van der Waals interactions between the sheets can be easily broken, so MoS2 is a superior lubricant with a very low friction coefficient. Compared with ordinary MoS2, nano-MoS2 has a much lower friction coefficient and much better effect of anti-wear and friction reducing. Due to nano-size effect, the interface between nano-MoS2 and rubber matrix has been enhanced, so nano-MoS2 is a promising wear-resistant filler for rubber composites.In the first part, the best experimental conditions for liquid exfoliating MoS2 using three instruments (Ultrasonic cleaner machine、 Ultrasonic cell crusher and High speed ball mill) have been studied. The surface morphology and thickness of MoS2 have been investigated by SEM and TEM. The results showed that all the three instruments can successful exfoliate MoS2 to thinner layers. The optimal time for liquid exfoliating MoS2 is one hour、8 times and one hour respectively.In the second part, we studied the influence on the properties of the MoS2/carbon black/nitrile butadiene rubber (NBR) composites and the MoS2/carbon black/natural rubber (NR) composites with different dosage of MoS2. We founded that MoS2 maintained its original layered structure in the NBR composites and the abrasion resistance property of the NBR composites filled with exfoliated MoS2 exhibits an increased trend while the composites filled with un-exfoliated MoS2 exhibits a decreased trend. The properties of the NR composites are not reinforced as the content of exfoliated MoS2 increasing. This may be related to the structure of natural rubber.In the third part, MoS2/SBR composites and MoS2/carbon black/SBR composites are prepared by a latex co-coagulation method. We studied the effect on the properties especially the abrasion resistance property of the composites with the increasing content of MoS2. The results show that the mechanical properties and abrasion resistance property of the two systems are enhanced with the increasing loading of MoS2, and the properties of the MoS2/SBR composites are enhanced more.In the fourth part, the effect of the different concent of MoS2 on the properties of the MoS2/silica/SBR composites is discussed. In the silica filled rubber system, the mechanical properties of the composites exhibit a little increased trend, but the abrasion resistance property is improved greatly. Compared with only silica filled systems, the volume loss of the composites filled with 10 phr MoS2 after Akron abrasion test is descreased by 46%.In the fifth part, MoS2-VPR/SBR composites are prepared by replacing the SBR latex with as much VPR latex in the flocculation process. The properties of the composites are investigated. The results show that, the composites possess superior mechanical properties with the increasing MoS2 laoding. With the same concent of MoS2,the mechanical and abrasion resistance properties of the MoS2-VPR/SBR composites are more outstanding than those of the MoS2/SBR composites which are not reinforced by VPR. This is because that VPR can act as a bridge which can strengthen the interface of MoS2 and SBR. The wear resistance property of the composite which is filled with 2 phr MoS2 is the best and the volume loss is as low as 0.23cm3/1.61km.