Surface structure of Kevlar® fiber studied by atomic force microscopy and inverse gas chromatography

Differential water sorption studies on KevlarTM 49 and as-polymerised poly (p-phenylene terephthalamide): adsorption and desorption isotherms

“…Shifts in the peak associated with the SAXS pattern as a function of time, as the uptake experiment proceeds, suggests lateral swelling of these microvoids. More recent studies using AFM techniques (Rebouillat et al, 1999) have reinforced the observations already presented, particularly with regard to the presence of microvoids between microÿbrils.…”

Microstructural developments of poly (p-phenylene terephthalamide) fibers during heat treatment process: a review

“…They found that, the surface fibrils are uniformly axially oriented, while the core ones are imperfectly packed and are ordered (so, voids will be formed in the core): Figures 17 and 18. They, also, found that the difference in skin-core structure is more clear in the less crystalline regions on the surfaces of Kevlar fibers 49 , and that this difference in skin-core structure is related to the fiber orientation and to the perfection of the chain packing a cross the fibers 40 . Yang 13,28 reported that the skin-core structure difference in density, voids and fibrillar orientation results from the fiber coagulation process.…”

Effects of chemical composition and post-spinning stretching process on the morphological, structural, and thermo-chemical properties of electrospun polyacrylonitrile copolymer precursor nanofibers

“…The results indicated that, the stretched electrospun binary-PAN nanofibers possessed the most desired thermo-chemical properties, macromolecular regularity, crystal and macromolecule orientations, and dimensional stability; and thus they are suitable for the development of high-performance carbon nanofibers. Carbon fibers derived from polyacrylonitrile (PAN) copolymer precursor fibers possess superior specific strength and modulus, and thus have been widely utilized for the fabrication of high-performance structural composites [1][2][3][4]. However, the strongest carbon fibers that are commercially available nowadays have the tensile strength of merely 7 GPa; whereas the theoretical tensile strength of carbon fibers is over 180 GPa [3,4].…”