Study On Preparation And Properties Of SiO₂-Al₂O₃/PU-EP Composites

The development process of epoxy resin has a long time since it was applied.The production of epoxy resin is more and more increased, and the application ofepoxy resin become more widely. The epoxy resin plays a very important role inthe field of thermosetting plastics. It was widely used in aerospace, military,electronics and construction, due to the excellent performance of epoxy resin.PU-EP precursor was prepared by epoxy as matrix, methyl tetrahydrophth-alic anhydride as the curing agent, polyurethane as toughening agent. PU-EP wasused as organic pure polymers. nano-particles was modified by the silanecoupling agent （KH-550, KH-560）, and SiO₂-Al₂O₃/PU-EP composite materialwas prepared at last，which was mainly used in the adhesive.The microstructure of the composite material and the dispersion of SiO₂andAl₂O₃in matrix were observed by SEM, FT-IR, AFM and XRD; The heatresistance, dielectric properties, shear properties and breakdown strength weretested by TGA, impedance meter, electronic universal tensile testing machine andpressure resistance test. The results indicated that nano-SiO₂and nano-Al₂O₃evenly dispersed in the PU-EP matrix when the weight of the nano-particles were10wt%of the epoxy matrix. The effect of dispersion of nano-particles was thebest when the mass ratio of nano-SiO₂and nano-Al₂O₃was4.5:5.5, nano-particles were uniformly dispersed in the “island structure”, and the maximumshear strength of the specimen was28.5MPa, that was increased by23%thanPU-EP（22.13MPa）. When the mass ratio of nano-SiO₂and nano-Al₂O₃was4.5:5.5, the maximum dielectric constant of composite was4.56. The dielectricconstant of SiO₂-Al₂O₃/PU-EP composite material showed downward trend whenthe amount of nano-SiO₂was increased, the maximum breakdown strength ofcomposite was15.0kV/mm when the mass ratio of nano-SiO₂and nano-Al₂O₃is4.5:5.5. The thermal decomposition temperature was increased when inorganic nano-particles were added to the composite material. When the proportion ofnano-SiO₂was increase, thermal decomposition temperature, Td5and Td10showedrise trend. The thermal decomposition temperature was the highest when themass ratio of nano-SiO₂and nano-Al₂O₃is9:1, that was increased by0.84%thanthat of PU-EP.