Synthesis,Structure And Properties Of Organic-inorganic Polymer Hybrids Containing Polyhedral And Macrocylic Oligomeric Silsesquioxanes

Organic-inorganic hybrid polymers have broad applications because they combined the properties of organic and inorganic components.However,the inorganic components are generally hard to disperse in the organic components because of the big different in solubility,which affected the synergism of both of the components.Therefore,how to make the inorganic components dispersed in an organic material at the nanoscale has become the key to prepare organic-inorganic hybrid materials.Silsesquioxane is a kind of excellent organic-inorganic molecular,which has cage or ring skeleton made of silicon-oxygen bond and organic groups as pendant.It has the size of only a few nanometers which provides the possibility of disperseing in organic material in nano-scale.In this paper,difunctional double-decker silsesquioxane（DDSQ）and twelve membered and twenty-four membered cyclic macrocyclic oligomeric silsesquioxane（MOSS）were synthesized,and functionalized by mercapto-vinyl addition reaction,click reaction,nucleophilic substitution reaction,hydrosilylation addition reaction or Heck reaction,then introduced into different materials to prepare organic-inorganic nanocomposites.The morphology and properties of organic-inorganic hybrid materials were studied.The main contents are as follows:（1）Synthesis and characterization of organic-inorganic nanocomposite polyimide（PI）materials by different topologies silsesquioxane.Synthesized two well-defined aniline-functionalized DDSQ and MOSS by 3,13-divinyl DDSQ and six-vinyl MOSS respectively through Heck reaction.This DDSQ or MOSS was further employed to synthesize the organic–inorganic polyimides nanocomposites.The formation of silsesquioxane microdomains in the organic–inorganic polyimides was investigated by means of transmission electron microscopy（TEM）;the thermomechanical properties of the organic–inorganic polyimides were examined by means of thermogravimetric analysis（TGA）and the surface contact angle measurements.The dielectric properties of the organic–inorganic polyimides were measured by broad-band dielectric spectroscopy（BDS）.（2）Synthesis and curing behavior of organic-inorganic polybenzoxazine（PBZ）containing silsesquioxane.Synthesized organic-inorganic polybenzoxazine hybrid resin by using 3,13-dianilino DDSQ.The formation of DDSQ microdomains in the organic–inorganic polybenzoxazine was investigated by means of transmission electron microscopy（TEM）;curing kinetics was studied by means of differential scanning calorimetry（DSC）,surface hydrophobic properties of nanocomposites was studied by means of static contact angle,thermal properties of the polymer were studied by dynamic mechanical thermal analysis（DMTA）and thermal gravimetric analysis（TGA）.（3）Synthesis,kinetics,and characterization of organic-inorganic poly（N-vinyl-2-pyrrolidone）copolymers with silsesquioxane.Synthesized a macromolecular chain transfer agent used for the RAFT/MADIX polymerization approach via a two-step reaction.First,3,13-di（2-bromo-propionate）propyl DDSQ was synthesized via the hydrosilylation between 3,13-dihydro DDSQ and 2-bromopropanoate.Thereafter,3,13-di（2-bromo-propionate）propyl DDSQ was allowed to react with equimolar 1,4-di（xanthate potassium）butane.This macromolecular chain transfer agent was further employed to synthesize the organic-inorganic polyvinyl pyrrolidone with DDSQ in the main chains.The kinetics of polymerization was studied by means of gel permeation chromatography（GPC）.The properties of the polymers were investigated by Fourier Transform infrared spectroscopy（FTIR）,Thermogravimetric Analysis（TGA）and differential scanning calorimetry（DSC）.Thereafter,the micellar behavior was investigated in terms of the measurement of fluorescence spectroscopy（FL）,dynamic laser scattering（DLS）and transmission electron microscopy（TEM）.（4）Synthesis and characterization of miktoarm brush with macrocyclic oligomer silsesquioxane as the ring skeleton molecular.First synthesized MOSS skeleton by metal induced complexed salt method,and functionalized by mercapto-vinyl addition,azides reaction and click reaction to achieve macromolecular chain transfer agent,and then synthesize the miktoarm brush of PVPy₁₂-MOSS-PCL₁₂ and PS₁₂-MOSS-PCL₁₂through reversible addition-fragmentation chain transfer radical polymerization（RAFT or RAFT/MADIX）and ring-opening polymerization（ROP）.For PVPy₁₂-MOSS-PCL₁₂,the nanostructures,thermal proporties and micellar behavior of the macrocyclic molecule brush polymer were investigated.For PS₁₂-MOSS-PCL₁₂,the nanostructures of the macrocyclic molecule brush polymer were investigated by means of small-angle X-ray scattering（SAXS）and atomic force microscopy（AFM）,while the thermal proporties was investigated in terms of thermal gravimetric analysis（TGA）.The melt crystallization behaviors of PCL were investigated by means of differential scanning calorimetry（DSC）.