Effects of Various Transition Metals on the Thermal Oxidative Stabilization of Polyacrylonitrile Nanofibers

Abstract In this paper, the polyacrylonitrile (PAN) nanofibers and PAN nanofibers bonded with different transition metal (Fe, Co, Ni, and Cu) acetates were successfully prepared and their thermal oxidative stabilization process were analysed by Fourier-transform infrared spectra (FT-IR) and differential scanning calorimetry (DSC). The structural evolution of process was characterized by examining the FTIR spectral peaks generated at four different thermal oxidative stabilization temperatures. Based on the thermal oxidative stabilization rates obtained from each transition metal, Co-PAN and Cu-PAN are the only effective precursors for the thermal oxidative stabilization process and, according to differential scanning calorimetry, Co-PAN is the most effective and suitable precursor for the PAN with different transition metals. Although Co-PAN increased the exothermic reaction (ΔH) by approximately 140%, it alleviates the heat release rate (ΔH/ΔT) by approximately 44%.

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Precipitation in silicon: Microanalysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100104431 ◽

1988 ◽

Vol 46 ◽

pp. 474-475

Author(s):

R.W. Carpenter

Keyword(s):

Transition Metals ◽

Spatial Resolution ◽

Thin Foil ◽

Precipitation Reaction ◽

High Current ◽

Reaction Products ◽

Carbon And Nitrogen ◽

Dielectric Layers ◽

Precipitation Processes ◽

Areas Of Interest

Interest in precipitation processes in silicon appears to be centered on transition metals (for intrinsic and extrinsic gettering), and oxygen and carbon in thermally aged materials, and on oxygen, carbon, and nitrogen in ion implanted materials to form buried dielectric layers. A steadily increasing number of applications of microanalysis to these problems are appearing. but still far less than the number of imaging/diffraction investigations. Microanalysis applications appear to be paced by instrumentation development. The precipitation reaction products are small and the presence of carbon is often an important consideration. Small high current probes are important and cryogenic specimen holders are required for consistent suppression of contamination buildup on specimen areas of interest. Focussed probes useful for microanalysis should be in the range of 0.1 to 1nA, and estimates of spatial resolution to be expected for thin foil specimens can be made from the curves shown in Fig. 1.

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