Microstructure And Properties Of The Ceramic Powder Surface Modification Of Polymer Matrix Composite Materials

Organic-inorganic hybrid composites combine both the advantages of organic polymer(lightweight,good impact resistance,flexibility and good process ability,etc.) and inorganic materials(high mechanical strength,good chemical resistance,thermal stability,etc.).Thus,this kind of composites attracts more and more interests of scientists,and has been widely applied in various fields.In this study,three kinds of organic-inorganic hybrid composites were prepared, which included curing technology,nanosilica/resin composites,nanoalumina/resin composites and TiB₂-Al₂O₃/resin composites.They were studied in detail,including the preparation methods,mechanical and thermal properties.Meanwhile,the effects of surface modification on the structure and properties were studied.Firstly,Three kinds of coupling agents were used to modify the surface of the silica, and they were(γ-aminopropyl) triethoxysilane(KH550),(γ-glycidoxypropyl) trimethoxysilane(KH560),(γ-Methacryloxypropyl)trimethoxysilane(KH570), respectively.Some characterization and analysis of the nanosilica treated by different kinds of coupling agents and the microstructure and heat resistant property of composites were performed by FTIR,Transmission electron micrograph(TEM),TGA and erosion testing machine.The results showed that the nanosilica treated by KH560 got the best dispersion in the matrix and thermal stability.Secondly,influences of inorganic nano-fillers(silica and alumina) on curing process were studied by gel times.The results displayed that the fill of nano-particles reduced the amount of curing agent and curing temperature.Nano-particles can be reduced by adding the amount of curing agent,lower curing temperature.The gel times of resins containing few nano-fillers were longer than those of corresponding unfilled resin.With the increase of content of the nano-fillers,the hydroxy functional groups increase,and the gel times of composites were shorter than those of corresponding unfilled resin.Compared with nano-alumina,nanosilica has the higher reactivity and a shorter gel times.The mechanisms by which the inorganic fillers make the gel times of resin longer were studied.Thirdly,particle size analyzer and TEM were used to investigate the particle size dispersions of three inorganic particles(nanosilica,nano-alumina and TiB₂-Al₂O₃) and the dispersions of two nano-fillers in the resin matrix.The results displayed that after surface modification,hydration sizes of particles were smaller,that is,surface modification improved the dispersion of particles in the solvent.Seen from the TEM photographs of nano-alumina/resin composites and surface treated nano-alumina/resin composites,surface modification also improved the dispersion of particles in the resin matrix.At last,the mechanical properties and thermal properties were inspected.The bending test showed that after modification,nano-fillers played a strengthened role to composites.When the particle content was three percent,the enhancing effect of borides was best in the three fillers.The erosion resistance properties were tested,and the impact angles were 90 or 45 degrees.The result displayed that nano-fillers improved the erosion properties of resin,and nano-alumina showed erosion resistant properties better than nano-silica.TGA results showed that nano-fillers improved thermal stability of resin.