Preparation Of NR-bases Wide Temperature Damping Material

Natural rubber(NR)has excellent comprehensive properties,good mechanical properties,processing properties,elasticity and fatigue resistance.However,the natural rubber molecular chain is flexible,the side base is sparse and the loss area provided by the structural unit is less,which results in the poor damping performance,which shows that the Effectsive damping temperature range is narrow and it is located in the low temperature region.However,high damping rubber such as butyl rubber(IIR)and nitrile butadiene rubber(NBR)have some disadvantages,such as low strength and difficult processing,which limit their application in the field of high comprehensive properties.Based on the expectation that the NR/NBR blends can integrate the excellent comprehensive properties of NR and the good damping properties of NBR,the research group has explored the damping properties of NR/NBR.It is found that NBR can improve the damping properity of NR and extend its Effectsive damping temperature range to room temperature.However,due to the poor compatibility between the two phases,there is a large wave valley between the damping peaks of the two phases and a damping defect zone with blends.In order to solving this problem,ethylene-vinyl acetate copolymer(EVA),high styrene rubber(HS-68),chloroprene rubber(CR),polyolefin elastomer(POE)and styrene butadiene rubber(SBR)were studied to investigate the Effects of on the compatibility and other properties of NR/NBR blends in this paper.The purpose of this study was to obtain the damping material of polyrubber in wide temperature range.On the basis of this,the Effects of the phenolic resin(PF),carbon black(CB)and several kinds of combined fillers on the properties of rubber was investigated.1.The results of adding EVA,HS-68,CR to the NR/NBR blends showed that EVA,HS-68 had no good Effects on improving the compatibility of the blends and their damping peaks appeared at 87.0 oC / 75.7 oC,respectively;CR raised a small damping peak between the damping peaks of NR-BR phase,partially filled the wave valley between the two phases but there was still a small wave valley between the NR-CR phase and all of them significantly improved the damping hysteresis of the blends.At the same time,appropriate amount of EVA can improve the mechanical properties of the blends,while HS-68 and CR have an adverse Effects on the mechanical properties of the blends.2.The Effects of POE and SBR on the properties of the blends were investigated by using NR/NBR/CR=70/30/30 as matrix.The results showed that POE could increase the tan?min at the NR-CR phase valley,but could not eliminate the existence of the valley.The wave valley between the phases in the blends was basically disappeared with the addition of SBR,but the tan? of the blends at low temperature was slightly lower and could not meet the requirement of application.Both POE and SBR can improve the damping hysteresis of the blends and the physical and mechanical properties of the blend can also be promoted when the content is appropriate.Finally,the Effects of NBR content on the properties of NR/SBR/CR blended was studied.It was found that when the content of NBR was 10 phr,there was a continuous high tan ?(tan ? ? 0.3)in-38.2 oC~22 oC,which Effectsively broadened the Effectsive damping temperature range of the blends.The properties of the obtained and used rubber dampers are the best.3.The Effects of several fillers on the properties of NR/SBR/CR/NBR=70/30/30/10 blends were studied.The results showed that the damping peaks of the blends containing both PF and hexamethylenetetramine(HMT)shifted slightly to the low temperature and the mechanical properties of the blends were improved,too,while the NBR phase in the blends without adding HMT shifted significantly to the high temperature and the damping temperature range of the blends is extended Effectsively,but the mechanical properties of the blends are reduced.CB can improve the mechanical properties of the blends,making the tan ? increase at high temperature and decrease the tan ? at low temperature.By increasing the ratio of non-CB phase in CB/ talc powder(TALC),CB/ kaolinite(MK),CB/ silica(Silica),the tan ? of the blends at low temperature can be significantly increased,while the tan ? at high temperature can be decreased to a certain extent.It has little Effects on the Effectsive damping temperature range and is helpful to the mechanical properties t of blends but it has certain requirements for the ratio of the two fillers and has an adverse Effects on the damping hysteresis performance of the blends.The addition of multi-walled carbon nanotubes(MWCNT)reduced the tan? of the blends at low temperature and the change of tan ? at high temperature was not obvious;the mechanical properties of the blends were decreased and the damping hysteresis was improved.