| The viscoelastic hysteresis properties of rubber material and various frictions between the macromolecular chains and the fillers causes the hysteresis loss of the rubber material,and the heat accumulation increases the temperature of rubber products.High temperature can lead to a series of problems of rubber products.The most serious consequence of heat is blasting-the explosive rupture of rubber products.The coupling agent modified silica has lower hysteresis loss than carbon black;and the aramid fiber?AF?reinforced rubber composite material has an important application value.Therefore,it is of great significance to investigate the effect of surface modification of aramid fiber on the heat generation of rubber.In this paper,silane coupling agents KH550,K570 and Si75 modified silica?white carbon?were used to fill styrene-butadiene rubber and the interaction between rubber and white carbon and the heat generation of composite materials were investigated.The methods of thermal oxidation treatment,latex impregnation,coating with the maleic anhydride polybutadiene?MLPB?and different concentrations of phosphoric acid were used to treat aramid fibers.The relationship between the crosslink density of the composites and the heat generation,and the effect of the surface bonding level between the aramid fibers and the rubber on the heat generation were investigated.The main content has the following aspects:?1?The maximum torque?ML?,the difference between the maximum torque and the minimum torque?MH-ML?,the degree of swelling,RPA and the scanning electron microscopy?SEM?results show:the white carbon black modified by the silane coupling agent is uniformly dispersed in the styrene-butadiene rubber,and the interaction force with the rubber increases.silica modified by silane coupling agent KH550 and styrene butadiene rubber have the greatest interaction force,and KH550 is grafted on rubber macromolecules during the vulcanization process.?2?The results of compression heat generation,dynamic mechanical properties?DMA?and hysteresis loss show that the heat generation of the modified SiO2/SBR composite material is reduced,and the greater the filler-rubber interaction force,the lower the heat generation.The heat generation of KH550-SiO2/SBR composites is significantly reduced.?3?After the aramid fiber was treated by thermal oxidation,latex impregnation and coating with MLPB,the stress at 100%,stress at 300%and tear strength of the composite material were significantly improved.The tensile fracture morphology and the calculated slippage energy show that the interfacial bond strength between AF and the rubber is improved by treatment of AF with the thermal oxidation,latex impregnation,coating with MLPB,and it was found that the latex impregnation and coating with MLPB decreased the crosslink density of the composites.The results of compression heat generation,DMA and hysteresis loss indicated that the heat generation of AF impregnated with latex or coated with MLPB was significantly higher.However,the heat generation of the thermal oxidation treated AF composites decreased,indicating that although the latex impregnation and coating with MLPB can improve the adhesion level between the AF and the rubber,but it decreases the crosslink density,so that the heat generation of the composite material is significantly increased.?4?The results of mechanical properties,RPA,SEM and slippage energy show that the interfacial adhesion between fiber and rubber matrix is improved with the increase of the concentration of phosphoric acid?H3PO4?.The results of compression heat generation,DMA and hysteresis loss show that with the increase of the concentration of phosphoric acid,the heat generation of the composite material decreases continuously,but the heat generation decreases slowly when the phosphoric acid concentration reaches 30%.?5?Through the study of the effect of carbon black?CB?content on the properties of rubber composites,it was found that when the content of carbon black was reduced to 35 phr,mechanical properties were still maintained,and heat generation was significantly reduced.Through the study of the properties of silica/carbon black/aramid fiber reinforced rubber composites,it was found that the payne effect of the composites was reduced with the addition of SiO2,and white carbon black has a synergistic effect on aramid fiber reinforced styrene-butadiene rubber.The results of compression heat generation,DMA and hysteresis loss show that the hysteresis loss and heat generation of SiO2 composites are lower than those of carbon black composites.Phosphoric acid modified AF can further reduce the hysteresis loss and heat generation of composites. |
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