| Fluorosilicone rubber,as a material closely related to national defense and military industry,has important strategic significance,and as polymer materials have also been more widely used in the field of optics,fluorosilicone rubber is one of the ideal choice of ultraviolet materials for its excellent optical properties.Not surprisingly,the presence of fluorine element has an important influence on its performance.Therefore,the study on the influence of the change of fluorine content on the properties of fluorosilicone rubber will be of great significance,which will also be beneficial to further promote the development of fluorosilicone rubber.In this paper,three specific structure kinds of hydrofluorosilicone oil and tetramethyltetravinylcyclotetrasiloxane are used for hydrosilylation reaction under the action of platinum catalyst to obtain a novel structure of high permeability ultraviolet fluorosilicone rubber.With the increase in A value,the ultraviolet transmittance increases first and then decreases.Besides,the increase of fluorine content will improve the optical performance of fluorosilicone rubber.The analysis of optical performance indicates that fluorosilicone rubber has good ultraviolet transmittance and optical transparency.The UV transmittance is up to 95.97%when F_H(0.3),A value is 2.0.Thermogravimetric analysis indicates that fluorosilicone rubber has excellent thermal stability,with a thermal decomposition temperature of up to 550.74 ~oC.On the one hand,the increase in crosslinking density can improve the thermal stability of fluorosilicone rubber;on the other hand,the increase in the content of trifluoropropyl will make the thermal stability of fluorosilicone rubber worse.The thermal analysis at 200 ~oC constant temperature shows that the rubbers can be used at this temperature for a long time,but the byproducts will slightly increase.Atomic force microscopy and scanning electron microscopy analysis describe that fluorosilicone rubber has good surface flatness,root mean square roughness RMS is 8.83 nm,and average surface roughness is 7.36 nm.The solvent resistance test proves that the fluorosilicone rubber has excellent solvent resistance to strong acids,strong bases,oils,and water,almost no reaction and swelling occurs,and it has a certain absorption of non-polar solvents,while the absorption of polar solvents is more and the rate of quality change is up to 72.14%.Not surprisingly,the fluorosilicone rubber prepared in this chapter are significantly harder than the current industrial rubber compound,showing obvious rigidity,with a minimum hardness of 45 and a maximum of81.Meanwhile,due to the presence of the vinyl ring body,the tensile strength of the fluorosilicone rubber has been improved to a certain extent,up to about 1 MPa,theproduct also shows obvious brittleness,the elongation at break is lower,the highest no more than 60%.The rheological dynamics of cross-linking during the isothermal curing of fluorosilicone rubber are studied by a rotary rheometer.The isothermal curing reaction at different A values and different temperatures is studied.The relationship between curing degree,curing time and curing rate was obtained.The gel point of the curing reaction was discussed,and the curing curve of fluorosilicone rubber is fitted using the Kamal and rheological model,thereby deepening the curing behavior of fluorosilicone rubber and declaring that the curing process is a complex process with autocatalysis and non-autocatalysis,which can be influenced by A values and temperature. |
PDF Full Text Request