The pyrolysis of acrylic fiber in inert atmosphere. I. Reactions up to 400°C

Abstract

synopsisThe pyrolysis of acrylic fiber up to 400°C in an inert atmosphere at 1 ' and G°C/min was studied by means of thermogravimetric and differential thermal analysis. The exothermic reaction occurring at 180-300°C was shown to be due to the reaction of nitrile groups by comparing the extent of exotherm with the number of nitrile groups present, determined by infrared spectroscopy. In addition, results of single-fiber tensile measurements, density, and elemental analysis of the pyrolyzed fibers are interpreted in terms of possible molecular structures. The gases evolved on pyrolysis were analyzed for both ammonia and hydrogen cyanide and the liberation of ammonia was attributed to a termination reaction of the polymerization of nitrile groups. The critical conditions necessary for the production of high strength and modulus carbon fiber are discussed briefly in relat.ion to the chemical changes occurring on pyrolysis.

Property changes of powdery polyacrylonitrile synthesized by aqueous suspension polymerization during heat-treatment process under air atmosphere

“…The first peak (lower temperature side) of these triplets was assigned to the primary oxidation (including dehydrogenation) and cyclization reactions, with the second peak and the third peak (higher temperature side) assigned to the secondary oxidation reactions leading to the polymer chain scission which causes the evolution of HCN, CO 2 and CO. This is consistent with the experimental results by many workers [8,[19][20][21].…”

Influence of γ‐ray irradiation on structure and properties of PAN precursor fibers

“…It was supposed that the difference of exothermic behavior chiefly lay in the initial step. The exothermic peak at 288°C of PAN precursors was an important feature of programmed pyrolysis in an inert atmosphere, which was corresponded to the cyclization reaction of nitrile groups . The results indicated that the kinetics of exothermic reaction, which was believed to be related to the cyclization process of nitrile groups, was significantly modified by γ‐ray irradiation.…”

Carbon film-coated 304 stainless steel as PEMFC bipolar plate

“…6 corresponds to the above assumption. G-band and D-band individually represent the resonances of carbon atoms in ordered and defective graphite structure [24,25]. The strong intensity and the narrow full width at half maximum (FWHM) of G-band signify the carbon film containing an abundance of ordered graphite structures, which could be attributed to highly ordered graphite layer developed early in the CVD process.…”