Monodisperse core/shell latex particles composed of a polystyrene(PS) core and a thin conductive polypyrrole (PPy) shell were synthesized by means of two-stage emulsion polymerization. Proofs for the success of core/s...Monodisperse core/shell latex particles composed of a polystyrene(PS) core and a thin conductive polypyrrole (PPy) shell were synthesized by means of two-stage emulsion polymerization. Proofs for the success of core/shell synthesis were obtained by using transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy(XPS). Pressed pellet conductivity measurements on the dried composites indicated a low percolation threshold of 13.8%. The conductivity for the composites was higher than that of a heterogeneous admixture of dried PS latex and PPy bulk powder. The highest conductivity of the core/shell composite was 0.14 S/cm.展开更多
Monodisperse polypyrrole（PPy） composite microspheres and hollow capsules based on the monodisperse core-shell gel template particles were prepared. The core-shell gel particles were obtained by the inward sulfonatio...Monodisperse polypyrrole（PPy） composite microspheres and hollow capsules based on the monodisperse core-shell gel template particles were prepared. The core-shell gel particles were obtained by the inward sulfonation of monodisperse polystyrene particles. The shell thickness and core size were synchronously controlled in the particle radius range. After the polymerization initiated by ammonium per sulfate（APS）, PPy was formed in the sulfonated polystyrene shell. PPy hollow capsules were derived after the polystyrene cores were dissolved: their cavity size and shell thickness were synchronously controlled by using core-shell gel particles with different sulfonation extent. It is interesting that if Fe3+ was adsorbed into the sulfonated polystyrene shell as the initiator, the PPy-shell collapsed into a pile of small particles when the polystyrene core was dissolved.展开更多
The thermal decomposition behaviors of four chemically modified polyethylene were investigated by high resolution pyrolysis gas chromatography\|mass spectrometry (HR PyGC-MS).The results revealed that substituents att...The thermal decomposition behaviors of four chemically modified polyethylene were investigated by high resolution pyrolysis gas chromatography\|mass spectrometry (HR PyGC-MS).The results revealed that substituents attached to maleated polyethylene as amides formed from secondary amines are significantly less stable than imides formed from primary amines.N-methylaniline amide-derivatives of maleated polyethylene undergo significant decomposition at 160℃ and substantial decomposition at 200℃.In contrast,the imides (except aniline imide) derivatives of maleated polyethylene are stable for long periods of time at 160℃,and the decomposition of phenethylamine imide-,9-aminomethylphenanthrene imide-derivatives is initiated slowly at 255℃ and 280℃,respectively.The effect of different modified groups on thermal stability of the polymers was discussed based on the qualitative and quantitative determination of the products.The thermal degradation pathways for the above chemically modified polyethylene were suggested.展开更多
文摘Monodisperse core/shell latex particles composed of a polystyrene(PS) core and a thin conductive polypyrrole (PPy) shell were synthesized by means of two-stage emulsion polymerization. Proofs for the success of core/shell synthesis were obtained by using transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy(XPS). Pressed pellet conductivity measurements on the dried composites indicated a low percolation threshold of 13.8%. The conductivity for the composites was higher than that of a heterogeneous admixture of dried PS latex and PPy bulk powder. The highest conductivity of the core/shell composite was 0.14 S/cm.
文摘Monodisperse polypyrrole（PPy） composite microspheres and hollow capsules based on the monodisperse core-shell gel template particles were prepared. The core-shell gel particles were obtained by the inward sulfonation of monodisperse polystyrene particles. The shell thickness and core size were synchronously controlled in the particle radius range. After the polymerization initiated by ammonium per sulfate（APS）, PPy was formed in the sulfonated polystyrene shell. PPy hollow capsules were derived after the polystyrene cores were dissolved: their cavity size and shell thickness were synchronously controlled by using core-shell gel particles with different sulfonation extent. It is interesting that if Fe3+ was adsorbed into the sulfonated polystyrene shell as the initiator, the PPy-shell collapsed into a pile of small particles when the polystyrene core was dissolved.
文摘The thermal decomposition behaviors of four chemically modified polyethylene were investigated by high resolution pyrolysis gas chromatography\|mass spectrometry (HR PyGC-MS).The results revealed that substituents attached to maleated polyethylene as amides formed from secondary amines are significantly less stable than imides formed from primary amines.N-methylaniline amide-derivatives of maleated polyethylene undergo significant decomposition at 160℃ and substantial decomposition at 200℃.In contrast,the imides (except aniline imide) derivatives of maleated polyethylene are stable for long periods of time at 160℃,and the decomposition of phenethylamine imide-,9-aminomethylphenanthrene imide-derivatives is initiated slowly at 255℃ and 280℃,respectively.The effect of different modified groups on thermal stability of the polymers was discussed based on the qualitative and quantitative determination of the products.The thermal degradation pathways for the above chemically modified polyethylene were suggested.
