The ultrafine nickel particles/polyaniline nanocomposite materials were synthesized in situ polymerization by two step series W/O inverse microemulsion systems. As the first step, the ultrafine nickel nanoparticles wh...The ultrafine nickel particles/polyaniline nanocomposite materials were synthesized in situ polymerization by two step series W/O inverse microemulsion systems. As the first step, the ultrafine nickel nanoparticles whose diameter is 10～30 nm were prepared by the W/O inverse microemulsion systems and by the reduction. As the second step, the monomer aniline salt (AnH +Cl -)entered into the polar waterpools where contained nickel nanoparticles and the ultrafine nickel particles/Polyaniline nanocomposite materials whose diameter is 50～100 nm had been obtained by in situ polymerization. These nanocomposite materials were measured to characterize and the micromorphology, microstructure and physical interaction of the both ultrafine nickel particles and polyanilines were studied by transmission electron microscopy (TEM), XRD, infraed spectrum (IR).展开更多
The encapsulation of stearic acid coated nanometer CaCO3 by a polystyrene (PS) network via emulsion polymerization is described, where gamma-methacryloxypropyltrimethoxysilane (MPS) was used as an efficient crosslinke...The encapsulation of stearic acid coated nanometer CaCO3 by a polystyrene (PS) network via emulsion polymerization is described, where gamma-methacryloxypropyltrimethoxysilane (MPS) was used as an efficient crosslinker. The important factors such as the type and amount of surfactant and initiator and the content of CaCO3 are investigated as well as the role of MPS. It has been shown that little PS was extractable with only 0.6 wt% of MPS (relative to styrene). The cationic surfactant cetyl trimethylammonium bromide (CTAB) proved more effective than the anionic surfactant sodium dodecyl sulfonate (SDS). The yield rises, particles become smaller and size distribution broadens with increased amount of CTAB. It is also found that either 2,2'-azobis(isobutyronitrile) (AIBN) or ammonium persulfate (APS) is suitable for attaining high monomer conversion. With increased amount of CaCO3, the encapsulation ratio can be varied from 17.9 to 3.6, while monomer conversion and yield decrease slightly. FT-IR spectra of the products after extraction indicate tight encapsulation between PS and CaCO3, and TEM photographs of composite particles with well-defined core-shell structure give direct evidence of encapsulation.展开更多
Poly(organophosphazenes) have potential applications in making water-soluble and biocompatible quantum dots (QDs) due to their wide variety of properties. The CdSe QDs of green emission and the core-shell CdSe/ZnS QDs...Poly(organophosphazenes) have potential applications in making water-soluble and biocompatible quantum dots (QDs) due to their wide variety of properties. The CdSe QDs of green emission and the core-shell CdSe/ZnS QDs of red emission were prepared. Subsequently the trioctylphosphine oxide-stabilized CdSe/ZnS QDs were transferred from chloroform into water through a ligand exchange process with poly(glycino amino acid)phosphazenes, which can be obtained from the saponification of poly (glycino amino ester)phosphazenes at room temperature. The resulting QDs-polymer nanocomposite particles can form colloidally stable suspensions in water and exhibit good photostability.展开更多
文摘The ultrafine nickel particles/polyaniline nanocomposite materials were synthesized in situ polymerization by two step series W/O inverse microemulsion systems. As the first step, the ultrafine nickel nanoparticles whose diameter is 10～30 nm were prepared by the W/O inverse microemulsion systems and by the reduction. As the second step, the monomer aniline salt (AnH +Cl -)entered into the polar waterpools where contained nickel nanoparticles and the ultrafine nickel particles/Polyaniline nanocomposite materials whose diameter is 50～100 nm had been obtained by in situ polymerization. These nanocomposite materials were measured to characterize and the micromorphology, microstructure and physical interaction of the both ultrafine nickel particles and polyanilines were studied by transmission electron microscopy (TEM), XRD, infraed spectrum (IR).
文摘The encapsulation of stearic acid coated nanometer CaCO3 by a polystyrene (PS) network via emulsion polymerization is described, where gamma-methacryloxypropyltrimethoxysilane (MPS) was used as an efficient crosslinker. The important factors such as the type and amount of surfactant and initiator and the content of CaCO3 are investigated as well as the role of MPS. It has been shown that little PS was extractable with only 0.6 wt% of MPS (relative to styrene). The cationic surfactant cetyl trimethylammonium bromide (CTAB) proved more effective than the anionic surfactant sodium dodecyl sulfonate (SDS). The yield rises, particles become smaller and size distribution broadens with increased amount of CTAB. It is also found that either 2,2'-azobis(isobutyronitrile) (AIBN) or ammonium persulfate (APS) is suitable for attaining high monomer conversion. With increased amount of CaCO3, the encapsulation ratio can be varied from 17.9 to 3.6, while monomer conversion and yield decrease slightly. FT-IR spectra of the products after extraction indicate tight encapsulation between PS and CaCO3, and TEM photographs of composite particles with well-defined core-shell structure give direct evidence of encapsulation.
基金Project(2006CB601005) supported by the National Basic Research Program of Chinaproject(200331) supported by the National Excellent Doctoral Dissertations of Chinaproject(Q5009001200801) supported by the Post-Doctoral Science and Technology Foundation from Beijing University of Technology
文摘Poly(organophosphazenes) have potential applications in making water-soluble and biocompatible quantum dots (QDs) due to their wide variety of properties. The CdSe QDs of green emission and the core-shell CdSe/ZnS QDs of red emission were prepared. Subsequently the trioctylphosphine oxide-stabilized CdSe/ZnS QDs were transferred from chloroform into water through a ligand exchange process with poly(glycino amino acid)phosphazenes, which can be obtained from the saponification of poly (glycino amino ester)phosphazenes at room temperature. The resulting QDs-polymer nanocomposite particles can form colloidally stable suspensions in water and exhibit good photostability.
