Design And Preparation Of Natural Rubber/bromobutyl Rubber Composite For Vibration Isolation Bearing

China is deeply troubled by earthquake disasters.It is equipped with seismic isolation rubber bearings on the foundation of the building to absorb vibration,which can effectively reduce the damage capability of earthquakes to buildings.The inner rubber material used for the high damping rubber bearing must have excellent overall properties,including high elasticity,high strength,high flexibility and high damping.Natural rubber has high strength,good elasticity and low compression set,but the short plate in damping performance limits its application in high damping isolation bearings.In this paper,natural rubber(NR)is used as the matrix,bromobutyl rubber(BIIR)is added as the damping phase,epoxidized natural rubber(ENR)is added to improve the compatibility of NR and BIIR,and C5 petroleum resin is added to make the composite' damping temperature range moves toward the high temperature direction,and finally carbon black is added to reinforce the composite.The microstructure,Tg,damping properties and physical and mechanical properties of various composite materials were tested through SEM,AFM,DMA,DSC,RPA and other testing methods.After careful research and analysis,NR/BIIR/ENR/C5 composites with potential applications in highly damped supports were finally prepared.The followings are major research details and results:(1)NR/BIIR composites with different ratios were prepared.When the ratio of NR/BIIR is 80/20,BIIR was mainly dispersed in the NR matrix as“island phase".With the increase of BIIR fractions,the structure gradually transformed into a dual continuous phase structure.Only one glass transition temperature appears in the NR/BIIR composite.As the number of BIIR increases,the loss factor peak of the composite decreases.The effective damping temperature range(tan??0.3)widens from 31.80C to 56?,and the relative hysteresis energy density significantly increased,the damping properties of the composite material were significantly improved.(2)NR/BIIR/ENR composites were prepared by selecting NR/BIIR(50/50)as the matrix and adding different parts of ENR.The addition of ENR can accelerate the vulcanization of the composite;the ENR is dispersed at the interface between the NR phase and the BIIR phase,and the size of the NR and BIIR bicontinuous phase becomes smaller as the number of ENR fractions increases,indicating the good compatibility between NR and BIIIR.The damping property of the composite material is obviously improved in the temperature range of 0?20?.When 20 phr of ENR is added,the effective damping temperature ratio of the composite material is increased by 8? by adding ENR;the addition of ENR slightly increases the tearing of the composite material.Elongation and tensile strength.(3)NR/BIIR/C5 composites were prepared by selecting NR/BIIR(50/50)as the matrix and adding different phr of C5 petroleum resin.The addition of C5 petroleum resin can significantly delay the vulcanization process of the composite,improve the damping performance of the composite in the high temperature region,and significantly improve the mechanical properties of the composite.The addition of 20 phr of C5 petroleum resin can shift the effective damping temperature range of the composite to 9? in the high temperature direction,increase the tensile strength by 27%,and increase the elongation at break by 38%.(4)Reinforce the NR/BIIR/ENR/C5(50/50/20/20)composite by adding carbon black with different particle sizes and different parts.The results show that the addition of carbon black does not affect the vulcanization rate of the composite,but due to the formation of the filler network,the crosslink density of the composite is significantly improved.The addition of carbon black will narrow the effective damping temperature range of the composite.Adding the same number of carbon black,the composite material with large particle size carbon black will have better damping performance in the low temperature zone,and the composite of small particle size carbon black will be added.The material has a higher loss factor in the high temperature zone,and the widest effective damping temperature range is as high as 72?,which is significantly higher than the effective damping temperature range of pure natural rubber(31.80C),and the effective damping temperature range is also from the right end of the temperature range.It increased to nearly 20 ?near 30? and increased by nearly 50?.The addition of 10 parts of carbon black N220 reinforced composite has a tensile strength of more than 10 MPa and an elongation at break of nearly 600%,which has the potential to be applied to high damping rubber bearings.