Analysis of the tensile moduli affected by microstructures among seven types of carbon fibers

Synthesis and Processing of Melt Spun Materials from Esterified Lignin with Lactic Acid

“…According to the literature [46,47], as far as the orientation is concerned, it was not substantially modified after the tensile test, which was a promising indication for potential thermal treatment (stabilization, carbonization), because during these processes, the fibers tend to shrink and become thicker. Furthermore, these values are related and comply with the tensile properties of natural fiber composites [48], while the difference between the precursor fiber in tensile strength is ascribed to their slightly different microstructure, which is affected by extrusion speed, temperature, and residence time of the materials in the extrusion line and the size of the spinneret [49]. Further, the tensile deformation and damage of fibers are strongly affected by both defects and orientation [50], while the chemical bonding has a severe impact on stiffness and tensile strength of fiber network [51].…”

The Non-Linear Elasticity of Unidirectional Continuous Carbon Fibre-Reinforced Composites and of Carbon Fibres

“…Loidl et al [ 31 ] showed, for PAN-based fibres, that the increase in processing temperature from low for SM fibres (around 1800 °C) to high for HM fibres (2400 °C) passing through intermediate for IM fibres (2100 °C) results in a decrease in the interlayer spacing, and an increase in crystallite size and in crystallinity. The tensile modulus increases with the increase in three factors of the crystallites: their aspect ratio, their volume fraction and their degree of orientation [ 32 ]. A skin–core description of the fibres, combining amorphous and crystalline regions in the fibre core with a skin layer exhibiting a higher degree of orientation, was proposed by Kobayashi et al [ 33 ] and can help in understanding recent results of mechanical properties of the core of fibres [ 12 , 34 ].…”

Atomistically informed hierarchical modeling for revisiting the constituent structures from heredity and nano–micro mechanics of sheath-core carbon fiber

“…For the last scheme combining the nano-scale structural features and micromechanics effective mean field (EMF) models such as the variational principle methods or Eshelby inclusion methods, 17 existing rotational-inclusion-based micromechanical models assume the unitary average orientation angle conditions, but these models will highly overestimate the off-axis modulus, giving more realistic statistically distributed orientation angles, especially containing large orientation angles. [18][19][20] Secondly, nano-pore components with direct SAXS evidences 21 were undifferentiated in the above crystalline/amorphous carbon twophase models, which will affect the forecasted precision. Additionally, indeterminate constituent phase properties remain to be resolved including the amorphous carbon modulus, which was inconsistently reported (o10 GPa by Tane, 18 120 GPa by Zhong, 19 or 200 GPa by Tanaka 20 ), as well as the modulus variations from the skin and core structures under different orientation angles.…”

“…[18][19][20] Secondly, nano-pore components with direct SAXS evidences 21 were undifferentiated in the above crystalline/amorphous carbon twophase models, which will affect the forecasted precision. Additionally, indeterminate constituent phase properties remain to be resolved including the amorphous carbon modulus, which was inconsistently reported (o10 GPa by Tane, 18 120 GPa by Zhong, 19 or 200 GPa by Tanaka 20 ), as well as the modulus variations from the skin and core structures under different orientation angles. The global statistical features can hardly be characterized from experiments; thus, it is necessary to revisit the nanocomposite microstructures within the sheath-core carbon fiber and develop hierarchical models from the molecular models to the micromechanics model where molecular models facilitate the extraction or identification of atomistic information and micromechanics models realize the prediction of the integral stiffness matrix.…”