Continuous carbonization of polyacrylonitrile‐based oxidized fibers: Aspects on mechanical properties and morphological structure

Abstract

SYNOPSISBy following the progression of continuous carbonization (300-1250°C ) of polyacrylonitrile (PAN) -based oxidized fibers, variations in tensile mechanical properties and morphological structure are reported in detail along the carbonization line. The tensile strength and Young's modulus of the fibers generally increase throughout the carbonization stage. Meanwhile, the fiber diameter displays a significant decrease. The preferred orientation of carbon layer planes is observed to increase remarkably for temperatures over 400°C. In a similar manner, the stacking size increases significantly but reaches saturation around 600°C, a changing point corresponding to that observed for the variation of the Young's modulus. However, beyond about 1200"C, the stacking size again displays a marked increase. Results thus obtained are interpreted in relation to each other. Possible implications are also discussed.

Multi-step mechanism of carbonization in templated polyacrylonitrile derived fibers: ReaxFF model uncovers origins of graphite alignment

“…For the SPP/ DLG system, the initial density was 1.40 g/cm 3 . The density choices are within the range of reported densities during carbon fiber production form PAN [42,43].…”

A review of heat treatment on polyacrylonitrile fiber

“…A few researchers had put in effort to understand the carbonization step especially in continuous model [21]. However, whatever be the technique, the process only occurs in inert atmosphere condition and usually involves heating the polymer in a nitrogen rich environment (Fig.…”

“…The successful conversion of PAN to high strength, high modulus fibers depend in part upon the understanding of the oxidative and thermal treatment. Liu et al [21] listed the three steps for the conversion of precursor of PAN-based fiber to carbon, which are as follows.…”

Influence of Poly(ethylene oxide) (PEO) Percent and Lignin Type on the Properties of Lignin/PEO Blend Filament

“…Continual spinning was achieved and satisfactory filaments were made from all samples with PEO percent 315%. This may be mainly attributed to the extensive cross-linking and strong intramolecular interactions of polymeric lignins disrupted through PEO blending, [26] thus altering the viscoelastic properties of lignin. Figure 1 shows the morphology of HWKL/ PEO blend filaments with different PEO content.…”

“…[26] Alcell and F 3 lignins also have lower phenolic hydroxyl group content, particularly condensed units, and a lower carboxylic group content than the corresponding HWKL produced from the same wood. [26] As a result, the molecules in both Alcell/PEO blend and F 3 /PEO blend molten solutions with the same PEO percent were easier to orientate along the drawing direction than those in HWKL/PEO blend molten solution, resulting in different crystallinity (Figure 10(c)). The intensity of Alcell/PEO blend is stronger than that of F 3 / PEO blend, and that of F 3 /PEO blend is stronger than that of HWKL/PEO blend.…”