Study On High Damping Rubber Material Suitable For A Wide Temperature Range Prepared By Blending

All kinds of mechanical equipments in operation produce different degree of vibrationand noise. Material damping is one of the most effective solutions to the problem of vibrationand noise, which has been explored by many researchers in recent years. The dampingproperty of polymer is generally governed by its behavior of transition or relaxation, whichare dominated by its components and structures. The damping usually peaks at or around theglass transition temperature of the material. The damping properties have been quantitativelyevaluated by the loss tangent maximum (tanδmax) and the temperature range (ΔT) for efficientdamping (tanδ>0.3). Good damping materials should exhibit a high loss factor (tanδ>0.3) overa temperature range of at least60~80℃. However, homopolymers usually exhibit efficientdamping in a narrow temperature range and only could be used at the temperature which isbelow the room temperature. That’s rather narrow for practical applications. Due to theunique “liquid-liquid” transition and the glass transition of butyl rubber and halogenated butylrubber, the loss peak is broad and high, which made them ideally suitable for using asdamping materials. Howerer, above10℃, the damping performance is not good enough.Therefore, considerable attention must been focused on broadening the damping range ofdamping rubber to higher temperature.The binary blends are prepared by weak polar Chlorinated Butyl rubber (CIIR) whichhas intensive side methyl and Nitrile Butadiene rubber (NBR) which contains a large amountof strong polar groups, which are investigated by dynamic mechanical analysis (DMA). It isshown that CIIR/NBR blends exhibit two kinds of relaxations and the low temperature peaksare related to Tg of CIIR, peaks at high temperature correspond to Tg of NBR. With NBR inthe vulcanized blends, the position of CIIR and NBR peaks shift to lower and highertemperature, respectively, this provides new paths for manufacture of promising noise andvibration damping materials. However, the tanδ value between peaks (tanδmin) is not highenough. When the blend ratio is80/20, tan δminis larger (0.27) than that of other CIIR/NBRblends. This leads to the damping range (tanδ＞0.2) covers a wide temperature range rangingfrom-80.5℃to120℃. The morphology of CIIR/NBR blends was investigated by SEM andTEM, and the relationship between microstructure and performance are explored, so as tofurther study of formula design of blends.The ternary blends are prepared by CIIR, NBR and CR, which are invested by DMA. Itis shown that damping properties of CIIR/NBR/CR ternary blends are better than that of CIIR/NBR binary blends for higher tanδ value between peaks. When30phr CR was added toCIIR/NBR (80/20) blends, the tanδminincreased to0.39(increased by44.4%). This leads tothe efficient damping (tanδ＞0.3) of CIIR/NBR/CR (80/20/30) blend covers a pretty widetemperature range from-88.5℃to71.5℃.The effects of carbon black concentration, naphthenic oil contents and various curingagents on the damping properties of CIIR/NBR/CR (80/20/30) blends were studied in detail.The tanδ value between peaks moves up to0.46with appropriate vulcanization system andcoordinate technology. The CIIR/NBR/CR (80/20/30) blend exhibits high damping at roomtemperature and shows efficient damping up to74.6℃with8phr Naphthene oil,40phrcarbon black and S/2402or S/1055curing agents. This opens up broad possibilities formanufacture of promising noise and vibration damping materials. Meanwhile, the ternaryblends have excellent comprehensive performance.