BaTiO3/polyurethane （BaTiO3/PU） nanocomposite elastomers were prepared from barium titanate nanoparticles, polyester polyol, 2, 4-toluene diisocyanate, 1,4-butanediol and 1, 1, 1-trimethanol propane by the one-step ...BaTiO3/polyurethane （BaTiO3/PU） nanocomposite elastomers were prepared from barium titanate nanoparticles, polyester polyol, 2, 4-toluene diisocyanate, 1,4-butanediol and 1, 1, 1-trimethanol propane by the one-step method. The density, hardness and dielectric constant of BaTiO3/PU nanocomposite elastomers increased with the increase of the content of BaTiO3 nanoparticles in nanocomposites. The electrostrictive properties of BaTiO3/PU nanocomposite elastomers were investigated by the digital speckle correlation method （DSCM）. It was found that through the on-and-off of the electric field, the electrostrictive strains of BaTiO3/PU nanocomposite elastomers revealed corresponding shrinkage and recovery. The electrostrictive coefficient of BaTiO3/PU nanocomposite elastomers was greater than that of the corresponding polyurethane elastomers, and the electrostrictive coefficient of composites decreased with the increase of the content of barium titanate nanoparticles.展开更多
The silicon-containing poly (amic acid)s were synthesized from bis (3, 4-dicarboxyphenyl) dimethylsilane dianhydride (SIDA), pyromellitic dianhydride (PMDA) and 4,4′-oxydianiline (4,4'-ODA) in N, N-dimethylacetam...The silicon-containing poly (amic acid)s were synthesized from bis (3, 4-dicarboxyphenyl) dimethylsilane dianhydride (SIDA), pyromellitic dianhydride (PMDA) and 4,4′-oxydianiline (4,4'-ODA) in N, N-dimethylacetamide (DMAc). The poly (amic acid) films were obtained by solution-cast method from DMAc solutions and thermally converted into transparent, flexible and tough polyimide films. The wide-angle X-ray diffraction diagrams revealed that all the polyimides possessed amorphous character, and the regulation of those polyimides were decreased with the increase of the molar ratio of SIDA to PMDA. Differential scanning calorimeter measurements showed that the introduction of SIDA to polyimide backbone would make glass transition temperature shift to lower temperature. Thermogravimetric analyses indicated that the silicon-containing polyimides lowered decomposition temperature as compared with PMDA/4, 4′-ODA polyimides. However, UV-visible transmission and reflection spectra showed that the optical transparency of silicon-containing polyimide thin films was superior to that of PMDA/4, 4'-ODA polyimide thin films.展开更多
文摘BaTiO3/polyurethane （BaTiO3/PU） nanocomposite elastomers were prepared from barium titanate nanoparticles, polyester polyol, 2, 4-toluene diisocyanate, 1,4-butanediol and 1, 1, 1-trimethanol propane by the one-step method. The density, hardness and dielectric constant of BaTiO3/PU nanocomposite elastomers increased with the increase of the content of BaTiO3 nanoparticles in nanocomposites. The electrostrictive properties of BaTiO3/PU nanocomposite elastomers were investigated by the digital speckle correlation method （DSCM）. It was found that through the on-and-off of the electric field, the electrostrictive strains of BaTiO3/PU nanocomposite elastomers revealed corresponding shrinkage and recovery. The electrostrictive coefficient of BaTiO3/PU nanocomposite elastomers was greater than that of the corresponding polyurethane elastomers, and the electrostrictive coefficient of composites decreased with the increase of the content of barium titanate nanoparticles.
文摘The silicon-containing poly (amic acid)s were synthesized from bis (3, 4-dicarboxyphenyl) dimethylsilane dianhydride (SIDA), pyromellitic dianhydride (PMDA) and 4,4′-oxydianiline (4,4'-ODA) in N, N-dimethylacetamide (DMAc). The poly (amic acid) films were obtained by solution-cast method from DMAc solutions and thermally converted into transparent, flexible and tough polyimide films. The wide-angle X-ray diffraction diagrams revealed that all the polyimides possessed amorphous character, and the regulation of those polyimides were decreased with the increase of the molar ratio of SIDA to PMDA. Differential scanning calorimeter measurements showed that the introduction of SIDA to polyimide backbone would make glass transition temperature shift to lower temperature. Thermogravimetric analyses indicated that the silicon-containing polyimides lowered decomposition temperature as compared with PMDA/4, 4′-ODA polyimides. However, UV-visible transmission and reflection spectra showed that the optical transparency of silicon-containing polyimide thin films was superior to that of PMDA/4, 4'-ODA polyimide thin films.
