Carbon nanotubes with diameters ranging between 140～220nm was synthesized with chemical vapor deposition method, and treated using nitric acid as oxidant. Pt/C catalysts were prepared using untreated and treated carb...Carbon nanotubes with diameters ranging between 140～220nm was synthesized with chemical vapor deposition method, and treated using nitric acid as oxidant. Pt/C catalysts were prepared using untreated and treated carbon nanotubes as supports, respectively. TEM and FT IR differential spectra showed that treated carbon nanotubes become short and possess more oxygen containing surface groups. The electrochemical studies indicated that the Pt/treated carbon nanotubes catalyst possessed much higher electrocatalytic activity for the oxidation of methanol than that of the Pt/untreated carbon nanotubes catalyst.展开更多
A kind of polyurethane/organically modified montmorillonite (PU/OMMT) nanocomposite based on poly(propylene glycol), 1,4 butanediol and 4,4 diphenylmethane diisocyanate was prepared by solution intercalation technolog...A kind of polyurethane/organically modified montmorillonite (PU/OMMT) nanocomposite based on poly(propylene glycol), 1,4 butanediol and 4,4 diphenylmethane diisocyanate was prepared by solution intercalation technology.The results of wide angle X ray diffraction and TEM showed that the gallery distance of OMMT in the PU matrix was 3～4?nm.As the hard segment content increased,the molecular chains of PU had difficulty in diffusing into the silicate layer galleries for intercalation.Transmission electron microscopy photographs showed that OMMT layers were dispersed well into the PU matrix on the nanometer scale,and an ordered intercalation structure was obtained.Compared with those of pure PU,the tensile strength,the tear strength and the elongation at break increased by about 43%,28% and 18% for PU/OMMT(92/8),respectively.The water absorption decreased with increasing the amount of OMMT.Thermogravimetric analysis showed that the PU/OMMT nanocomposites displayed a little higher thermal resistance than that of pure PU in the second pyrolysis stage.展开更多
文摘Carbon nanotubes with diameters ranging between 140～220nm was synthesized with chemical vapor deposition method, and treated using nitric acid as oxidant. Pt/C catalysts were prepared using untreated and treated carbon nanotubes as supports, respectively. TEM and FT IR differential spectra showed that treated carbon nanotubes become short and possess more oxygen containing surface groups. The electrochemical studies indicated that the Pt/treated carbon nanotubes catalyst possessed much higher electrocatalytic activity for the oxidation of methanol than that of the Pt/untreated carbon nanotubes catalyst.
文摘A kind of polyurethane/organically modified montmorillonite (PU/OMMT) nanocomposite based on poly(propylene glycol), 1,4 butanediol and 4,4 diphenylmethane diisocyanate was prepared by solution intercalation technology.The results of wide angle X ray diffraction and TEM showed that the gallery distance of OMMT in the PU matrix was 3～4?nm.As the hard segment content increased,the molecular chains of PU had difficulty in diffusing into the silicate layer galleries for intercalation.Transmission electron microscopy photographs showed that OMMT layers were dispersed well into the PU matrix on the nanometer scale,and an ordered intercalation structure was obtained.Compared with those of pure PU,the tensile strength,the tear strength and the elongation at break increased by about 43%,28% and 18% for PU/OMMT(92/8),respectively.The water absorption decreased with increasing the amount of OMMT.Thermogravimetric analysis showed that the PU/OMMT nanocomposites displayed a little higher thermal resistance than that of pure PU in the second pyrolysis stage.
