Structural Characterization of Thermally Stabilized Poly(acrylonitrile) Fibers by Means of X-ray Diffraction, FT-IR Spectroscopy, and TGA Analysis

Abstract

The structure and effects of thermally stabilized PAN original fibers were characterized utilizing a mixture of volume density, color change observations, flame tests, X-ray diffraction (XRD), infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA) measurements. The results obtained from the analysis of XRD work showed the conversion of the original molecular structure from a highly laterally ordered condition to a disordered amorphous structure. The experimental results acquired from FT-IR analysis indicated rapid and concurrent aromatization and dehydrogenation reactions assisted by the formation of oxygen-containing functional groups. TGA analysis showed a carbon yield of 72% at 1000 °C. The application and use of NH4Br pretreatment are expected to increase the productivity of carbon fiber processing at lowered cost by significantly reducing the processing time necessary for the successful completion of thermal stabilization reactions.

Critical Electrospinning Parameters for Synthesis Control of Stabilized Polyacrylonitrile Nanofibers

“…The cyclization process takes place between the carbon of the CN and the nitrogen of the CN adjacent to the PAN structure. The change in C≡N to C=N intensities in FTIR spectra can be quantified using Equation (4) [49]. Figure 5b shows a fast weight loss at 300 • C, which corresponds to the PAN oxidation processes that result in the carbon ladder structure (Figure 4).…”