The Study Of The Application Characteristics Of Fluorinated Silicon Rubber And Fluoroether Rubber Used At Extreme Environmetnt

In this paper,The performance characteristics and theory of aerospace industry related fluorinated silicon rubber(FS)and fluoroether rubber(FM)products used at extreme environment were comprehensively studied and analysed.And the optimization of the application performance of these two types specialty elastomer was preliminarily discussed.Firstly the mechanical properties,high and low temperature resistance properties and special oil resistance properties of domestic and Dow FS,high temperature type FM and ordinary FM were studied.All these properties were needed for these rubbers which will be used as aerospace industry related products at extreme environment.The result showed that the mechanical properties of domestic FS and Dow LS4 FS were equal.Both of them could meet the requirements of sealing products.The oil resistance properties of Dow FS were better than domestic FS,but both of them were not resistant to the high temperature 4109 lubricating oil The high temperature resistance property of these two kinds of FS were excellent which was equal to silicone rubber.The low temperature resistance properties of Dow FS were better than domestic FS.The compression set properties of Dow FS was outstanding and didn’t change with the changing of hardness.The compression set properties of domestic FS decreased with the increase of hardness.DMTS test showed that The glass transition temperature(Tg)of these two kinds FS was similar,around about-50 ℃.The mechanical properties of these two kinds FM were excellent.The high temperature type FM remained high performance after heating at 275 ℃ hot air for 72h,but the high temperature resistant of ordinary FM was slight poor.The oil resistance properties of these two kinds FM were outstanding.The compression set were low when FM were tested at room temperature and oil environment.But the compression set would be higher when FM were tested at high temperature air environment.Secondly,the high temperature aging behavior of FS and FM were studied.The result indicates that FS and FM still maintained good mechanical properties by heat ageing for 22d.The tan δ of FS decreased with the increase of aging time.And the Tg of FS increased with increase of aging time,but the variation was limited.The Tg of FM showed a increasing tendency with the increase of the aging time,but the tan δ almost remained the same.The storage modulus(E’)and loss modulus(E")of FS and FM almost remained the same during 22 days,which made sure that the rubber could achieve a fast-elastic recovery of the deformation with temperature.Finally,the effects of aluminum nitride(AIN),carbon nanotubes(CNTs)and graphite on the properties of FS were studied.The results showed that the thermal conductivity of FS increased gradually with the increase of content of AIN(10～60phr)and CNTs(2～6phr).At the same time,AIN and CNTs were good for the heat resistance and oil resistance properties of FS.When the FS was filled with 60phr AIN or 6phr CNTs the thermal conductivity of FS would amount to 0.463 w/m·k or 0.33 w/m k.With the increase of content of graphite,the thermal conductivity of FS increased gradually,but the mechanical properties of FS will decreased obviously.