Synthesis And Application Of Transition Metal Amino Silsequioxane Complex

Metal oligomeric silsesquioxane is a kind of catalyst based on organic-inorganic hybrid nanomaterial polyhedral oligomeric silsesquioxane(POSS).It has attracted much attention due to its excellent thermal oxygen stability,good mechanical properties and high catalytic activity.In this thesis,a series of polyhedral oligometalla silsesquioxane(POMSS)catalysts were prepared by reacting amino-containing POSS with acetylacetone transition metal compounds.Fourier transform infrared spectroscopy(FTIR),ultraviolet-visible spectroscopy(UV),gel permeation chromatography(GPC),X-ray diffraction(XRD),and other methods were used to characterize the structure of POMSS.A series of POMSS/CE hybrid materials were prepared by blending different kinds of POMSS with cyanate ester(CE).The curing mechanism and curing degree of the hybrid system were studied by FTIR.The curing behavior of the hybrid system was studied by differential scanning calorimetry(DSC).The addition of POMSS can significantly reduce the curing temperature and activation energy of CE.Especially,the catalytic effect of 2%Fe(?)-POSS is most remarkable.The peak curing temperature of CE is reduced from 308.8? to 140.?.The dynamic viscoelastic properties of hybrid materials are studied by dynamic mechanical thermal analysis(DMTA).The hybrid materials containing Co-POSS has higher storage modulus than that of pure CE in the low temperature range.The thermal stability of hybrid materials is studied by thermogravimetric analysis(TGA).The addition of Co-POSS significantly improved the thermal stability of CE,and the residual carbon at 750? also has increased.The cross-sectional morphology of the hybrid materials and the dispersion of the catalyst were observed by scanning electron microscopy(SEM).The POMSS changed the fracture mode of CE resin,the cross-section morphology was more complicated,and POMSS was well dispersed in the resin matrix.Two kinds of pyrener-containing derivatives(BZ and NMP)were synthesized for non-covalent modification of graphene,and the structures of BZ and NMP were characterized by FTIR,1H-NMR and elemental analysis.The surface adsorption amount of graphene was calculated by FTIR,UV and TGA.The modified graphene/Cu-POSS/CE hybrid system with different mass percentages was prepared.The curing kinetics,thermal conductivity,mechanical properties and thermal stability of the hybrid system were studied by DSC,thermal conductivity analyzer,DMTA and TGA,respectively.The results show that the addition of modified graphene reduces the activation energy of the hybrid system,the thermal conductivity is significantly improved,and the thermal stability and the residual carbon at 750? are significantly increased.