Study on Structure and Properties of HNBR/CR Blends and the Application of the Blends in Synchro Belt
|School||Qingdao University of Science and Technology|
|Course||Materials Processing Engineering|
|Keywords||HNBR/CR blends compatibility structure and properties synchrobelt|
Hydrogenated acrylonitrile butadiene rubber(HNBR) is a new-style special rubberwith excellent properties, but it’s price is very high because the synthetical technics and thedistill of activator are complicated. Besides, the conqlutinant property of HNBR is poor,these ill factors restrict the application of HNBR. It’s a good method to improve the poorproperties of HNBR and reduce the price of the products made of HNBR by inputtingchloroprene rubber（CR）into HNBR fraction. Compatibility of the blends was studied bythe DSC, DMA and IR. Tg of the blends before and after vulcanization was tested by DSCand DMA and structure of the blends was tokend by IR. The processing，mechanicalproperties, hot-air ageing，hot-oil ageing resistance properties, conqlutinant property of theblends affected by the proportion of HNBR/CR were studied. The hot-stability of theblends was studied by TG. HNBR and CR were blended at the ratio of70/30and propertiesof blends affected by assorted system and processing technics were studied. The109YUsynchro belt was made by the blends at the proportion of70/30and the static properties ofthe belts were tested.It was found that HNBR is incompatibility with CR before vulcanization, but becamecompatibility after vulcanization. With CR fraction increased，the vulcanized efficiencyand processing properties were improved and dynamic caloric，hot-air ageing，hot-oilageing resistance of the blends decreased. If the blending ratio (mass ratio) of HNBR/CRexceeds70/30，and the tensile strength， hot-air ageing and hot-oil ageing resistanceproperties of the blends are excellent，the blends can be applied to many circumstances ofhigh temperature and oil resistance. When the blending ratio was less than60/40，theproperties of mechanical，hot-air ageing and hot-oil ageing resistance decreased badly. TGanalysis reveals that the blends were decomposed in two steps. The blending between CR and HNBR can improve the hot-stability of CR fraction and keep the excellent hot-stabilityof HNBR fraction. Mechanical properties of the blends of HNBR/CR can be reinforced excellentlyby the short fibres when cotton and polyester short fibres were used together, and the mechanicalproperties of the blends were best when the usage of the short fibres was10per. When theblends(70/30) were vulcanized by peroxides, reinforced by black carbon N330/N550,intenerated by TP-95, protected by MB/RD and cured in170℃for40min at the firststemp,150℃for2h at the second step, it’s properties were best and the static properties ofthe belt made by the blends were excellent.