| The performance of composite can be greatly improved and the application rangecan be expanded by sepiolite fiber which was used as reinforcing materials of rubbermatrix for its excellent properties in adsorptive property and thermology. While theapplication of natural sepiolite mineral powder is limited by its low purity, poordispersion and weak ability to combines with polymeric matrix. Fluororubber that hasperformance of high-temperature resistance, oil resistance and chemical corrosionresistance is a special rubber, and it possesses better comprehensive properties. FE haslow interfacial adhesion strength with most of filler because of its unique chemicalstructure. So the special crystal structure of activated sepiolite can improve theinteraction between it with FE matrix. The activated sepiolite filled FE matrix, not onlyto expand the range of applications of sepiolite, also enables the application of fluorinerubber broader.In order to prepare the sample of Sepiolite/FE composite, starting from the processof activation of sepiolite, and crystal structure of sepiolite fiber are studied. Through thestudy of tetrapropanate fluorine rubber crosslinking mechanism, the relationship betweenthe fluorine rubber vulcanization reaction and the curing process is further grasped, andproviding a theoretical basis for the preparation of composite materials. Based on thecuring characteristics, physical properties, microstructure and characterization of thermalproperties of activation sepiolite/FE composite material, analyzed the mechanism of therole of activation sepiolite in FE composite material. This work is divided into threeparts:In the first part of the research contents, the effect of acid-and heat-activatedsepiolite was studied by thermogravimetry, X-ray diffraction, infrared, SEM and nitrogenadsorption-desorption method. The results show that the impurities such as calcite areremoved by acid-activation, which can remove the magnesium ions from the crystalstructure to make Si-O-Mg-O-Si into Si-OH so as to improve the mesopores ratio ofsepiolite. Sepiolite fibers are made into fiber tracts by heat-activation, the channels infiber tracts are mesopores commonly. So the mesopores ratios of SEP-E, SEP-EL,SEP-EM are above80%.In the second part of the study, the mechanism of tetrafluoroethylene-propylenerubber peroxide vulcanization in the presence of N, N’–meta-phenylene-bis-maleimide(MPBM) was studied. The effect of MPBM on the crosslinking reaction characteristics of tetrafluoroethylene-propylene rubber/DCP was investigated by MDR curometer and DSCmethod. The results showed that, β chain scission reactions are present intetrafluoroethylene-propylene rubber peroxide vulcanization, and the number of β chainscission reactions of tetrafluoroethylene-propylene radical increased in high temperature.As an effective coagent for tetrafluoroethylene-propylene rubber/DCP curing system,MPBM could improve the crosslinking efficiency and the rate of crosslinking reaction.The mechanism is that tetrafluoroethylene-propylene-MPBM radicals could form aneffective crosslinking and decrease the number of β chain scission reactions oftetrafluoroethylene-propylene radical.As for the third part, sepiolite/fluororubber composite was prepared by mixing andpress curing. The effect of activated sepiolite on the crosslinking reaction characteristics,tensile property, abrasion resistance and thermostability of tetrafluoroethylene-propylenerubber was investigated. It shows that activated sepiolite fiber can disperse evenly in thefluororubber matrix to improve the degree of crosslinking, hardness and abrasionresistance. As sepiolite fiber content was change, fluorine rubber composite materialstensile strength present a trend of decrease the tensile strength increases first. With theincrease of dosage of sepiolite, the thermal decomposition of the rubber is delayed, Sothe thermal stability of fluororubber can be improved. |
PDF Full Text Request