Study On The Synthesis And Performance Of Fluorine-containing Silicone Resin

Silicone resin has excellent high temperature resistance,electrical insulation and dielectric properties,and is often used in aerospace materials,chemical materials and coatings.Silicone resin has better thermal stability than other organic resins,but it still can't meet the requirements of harsh application environment.The perfluorocyclobutyl aryl ether(PFCB)structure is a new type of fluorine-containing structure.The benzene ring and perfluorocyclobutyl in the structure are rigid groups,so the heat resistance of the material is improved;The existence of ether bond is helpful to improve the flexibility of rigid molecular chain and the processability of silicon materials Fluorine-containing materials have hydrophobic properties because of the strong binding force of C-F bond and low free energy.According to the above characteristics,this paper introduced PFCB structure into methyl silicone resin and phenyl vinyl silicone resin,prepared a new type of fluorine-containing silicone resin,and preliminarily explored the relationship between PFCB content and material properties.In this paper,[4-trifluorovinyl aryl ether]methyl diethoxysilane,1,2,3,3,4,4-hexafluoro-1,2-bis[4-(dimethylsilyl)aryl ether]cyclobutane and Poly(1,1,3,3-tetramethyl-1,3-bis[4-trifluorovinyl aryl ether]disiloxane)were synthesized from 4-bromophenol and 1,2-dibromotetrafluoroethane by substitution,elimination,format reaction and hydrolysis,and its structure was characterized by FT-IR and NMR.Three kinds of highly crosslinked silicone resins containing PFCB structure were prepared by co-hydrolysis polycondensation and hydrosilylation,and their structures were characterized by FT-IR and NMR.The effects of PFCB content on the thermal stability,degradation behavior and hydrophobic properties of silicone resin were determined.During the curing process of silicone resin,TFVE units only forms PFCB structure by heating,which eliminates the coupling tension of unsaturated bonds and makes PFCB structure more stable.The results show that the modified silicone resin has excellent thermal stability and hydrophobic properties,and with the increase of PFCB structure content,it was more difficult to degrade in N₂ and air atmosphere.The curing time and temperature of silicone resin prepared by additive process were greatly reduced,and the preparation process was simpler.The resin has excellent thermal stability,and the higher the PFCB content,the more difficult it is to degrade in air.The introduction of PFCB structure improves the hydrophobic property of silicone resin to a certain extent.