scholarly journals Rheology of Polyacrylonitrile/Lignin Blends in Ionic Liquids under Melt Spinning Conditions

Molecules ◽  
2019 ◽  
Vol 24 (14) ◽  
pp. 2650 ◽  
Author(s):  
Jinxue Jiang ◽  
Keerthi Srinivas ◽  
Alper Kiziltas ◽  
Andrew Geda ◽  
Birgitte K. Ahring

Lignin, while economically and environmentally beneficial, has had limited success in use in reinforcing carbon fibers due to harmful chemicals used in biomass pretreatment along with the limited physical interactions between lignin and polyacrylonitrile (PAN) during the spinning process. The focus of this study is to use lignin obtained from chemical-free oxidative biomass pretreatment (WEx) for blending with PAN at melt spinning conditions to produce carbon fiber precursors. In this study, the dynamic rheology of blending PAN with biorefinery lignin obtained from the WEx process is investigated with the addition of 1-butyl-3-methylimidazolium chloride as a plasticizer to address the current barriers of developing PAN/lignin carbon fiber precursors in the melt-spinning process. Lignin was esterified using butyric anhydride to reduce its hydrophilicity and to enhance its interactions with PAN. The studies indicate that butyration of the lignin (BL) increased non-Newtonian behavior and decreased thermo-reversibility of blends. The slope of the Han plot was found to be around 1.47 for PAN at 150 °C and decreased with increasing lignin concentrations as well as temperature. However, these blends were found to have higher elasticity and solution yield stress (47.6 Pa at 20%wt BL and 190 °C) when compared to pure PAN (5.8 Pa at 190 °C). The results from this study are significant for understanding lignin–PAN interactions during melt spinning for lower-cost carbon fibers.

2012 ◽  
Vol 268-270 ◽  
pp. 483-486
Author(s):  
Yin Cai Tian ◽  
Ke Qing Han ◽  
Wen Hui Zhang ◽  
Jing Jie Zhang ◽  
Rui Zhang ◽  
...  

The carbon fiber has excellent properties; however, the high cost limited its wide application. Here we report a novel process to reduce the heat emission during stabilization by in situ modification of spinning melt. In this paper, the effect of extruding temperature on the structures of PAN in the PAN/ILs melt was investigated by twin-screw extruder. FTIR and UV-vis absorption spectra of modified samples showed the formation of C=C and C=N group, which indicated the occurrence of cyclization and dehydrogenation reactions of PAN during extrusion process. The degree of cyclization was calculated from DSC test and the degree of cyclization can be up to 24.5% with the residence time of 14 min at 210 oC, which could decrease the heat release in the subsequent stabilization process during carbon fiber production. Therefore, this method should be benefit to improve the processing efficiency during stabilization process.


BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 7234-7259
Author(s):  
Yongjian Xu ◽  
Yan Liu ◽  
Shenglin Chen ◽  
Yonghao Ni

Lignin, as a potential precursor of carbon fiber, has the characteristics of abundant reserves, renewable and high carbon content, and its application in the preparation of carbon fibers has substantial cost advantages if some important processing and quality hurdles can be overcome. This paper reviews the preparation process of lignin-based carbon fibers, and moreover, describes the characteristics of carbon fiber prepared by different precursors compared with the presently used precursors. Three preparation methods for lignin-based carbon fibers are introduced: melt spinning, solution spinning, and electrospinning. The applicability, advantages, and disadvantages of the three preparation methods are analyzed from the aspects of process conditions and performance characteristics. Possible directions for future research are considered, with the goal of providing a reference for further study of lignin-based carbon fibers.


2001 ◽  
Vol 702 ◽  
Author(s):  
J. Yan ◽  
A. D. Rey

ABSTRACTCarbonaceous mesophases are spun into high performance carbon fibers using the melt spinning process. The spinning process produces a range of fiber textures whose origins are not well understood. Planar polar (PP) and planar radial (PR) textures are two ubiquitous ones. A model that describes the formation process of the PP texture based on the Landau-de Gennes mesoscopic theory for discotic liquid crystals, including defect nucleation, defect migration, and overall texture geometry, is presented, solved, and validated. The computed PP and PR textures phase diagram, given in terms of temperature and fiber radius, is presented to establish the processing conditions and geometric factors that lead to the selection of these textures. The influence of elastic anisotropy to the textures formation and structure is also characterized.


2018 ◽  
Vol 48 (7) ◽  
pp. 1242-1253 ◽  
Author(s):  
Tae Hwan Lim ◽  
Moo Sung Kim ◽  
Sang Young Yeo ◽  
Euigyung Jeong

The purpose of this study is to investigate the potential of using a pelletized pitch in a continuous process for the economical preparation of large-scale pitch-based carbon fibers. The pitch was pelletized before spinning because the pitch powder can agglomerate in the feed throat of a screw extruder, which can render uniform heating difficult. Using the pelletized pitch in a single-screw extruder spinning apparatus, the pitch fiber can be spun to a great length as long as the amount of pitch pellets is sufficient. To evaluate the benefits of using pitch pellets in the continuous carbon fiber spinning process, isotropic and mesophase pitch fibers were prepared by both the conventional batch process using pitch powder and continuous process using pitch pellets. Even with a huge difference in the thermal energy used, the carbon fibers prepared using the pelletized-pitch-based continuous process had better tensile properties than those prepared using the conventional process. This suggests that the continuous process using pitch pellets has the potential to be an economical large-scale process for carbon fiber preparation.


2012 ◽  
Vol 538-541 ◽  
pp. 1281-1285
Author(s):  
Ju Mei Yuan ◽  
Yu Xiao Shen ◽  
Bin Liu ◽  
Min Zhou ◽  
Jun Qing Liu

In order to control the wire diameter stability for pitch carbon fiber melt-spinning effectively, this can affect the performance of carbon fiber. This paper presents an asphalt carbon fiber melt-spinning wire diameter stabilization method based on radial basis function neural network. Firstly, the relation model that pitch carbon fiber melt-spinning wire diameter, spinning temperature, spinning pressure and spinning roller speed was established through measured data based on radial basis function neural network. Then control the spinning temperature, pressure and spinning rollers speed coordination changes to ensure the stability of spinning wire diameter in spinning process. Finally, we apply this method to our laboratory measured data and compared with existing experience formula. The result shows that the method is feasible and effective


2003 ◽  
Vol 774 ◽  
Author(s):  
Janice L. McKenzie ◽  
Michael C. Waid ◽  
Riyi Shi ◽  
Thomas J. Webster

AbstractSince the cytocompatibility of carbon nanofibers with respect to neural applications remains largely uninvestigated, the objective of the present in vitro study was to determine cytocompatibility properties of formulations containing carbon nanofibers. Carbon fiber substrates were prepared from four different types of carbon fibers, two with nanoscale diameters (nanophase, or less than or equal to 100 nm) and two with conventional diameters (or greater than 200 nm). Within these two categories, both a high and a low surface energy fiber were investigated and tested. Astrocytes (glial scar tissue-forming cells) and pheochromocytoma cells (PC-12; neuronal-like cells) were seeded separately onto the substrates. Results provided the first evidence that astrocytes preferentially adhered on the carbon fiber that had the largest diameter and the lowest surface energy. PC-12 cells exhibited the most neurites on the carbon fiber with nanodimensions and low surface energy. These results may indicate that PC-12 cells prefer nanoscale carbon fibers while astrocytes prefer conventional scale fibers. A composite was formed from poly-carbonate urethane and the 60 nm carbon fiber. Composite substrates were thus formed using different weight percentages of this fiber in the polymer matrix. Increased astrocyte adherence and PC-12 neurite density corresponded to decreasing amounts of the carbon nanofibers in the poly-carbonate urethane matrices. Controlling carbon fiber diameter may be an approach for increasing implant contact with neurons and decreasing scar tissue formation.


2021 ◽  
Vol 70 (4) ◽  
pp. 767-772
Author(s):  
N. G. Mazhorova ◽  
P. V. Ivanov ◽  
O. V. Zaichenko ◽  
A. V. Lakhin ◽  
S. Yu. Kanterin ◽  
...  
Keyword(s):  

Polymers ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1319 ◽  
Author(s):  
Ran Li ◽  
Huiping Lin ◽  
Piao Lan ◽  
Jie Gao ◽  
Yan Huang ◽  
...  

Lightweight electromagnetic interference shielding cellulose foam/carbon fiber composites were prepared by blending cellulose foam solution with carbon fibers and then freeze drying. Two kinds of carbon fiber (diameter of 7 μm) with different lengths were used, short carbon fibers (SCF, L/D = 100) and long carbon fibers (LCF, L/D = 300). It was observed that SCFs and LCFs built efficient network structures during the foaming process. Furthermore, the foaming process significantly increased the specific electromagnetic interference shielding effectiveness from 10 to 60 dB. In addition, cellulose/carbon fiber composite foams possessed good mechanical properties and low thermal conductivity of 0.021–0.046 W/(m·K).


Buildings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 300
Author(s):  
Md. Safiuddin ◽  
George Abdel-Sayed ◽  
Nataliya Hearn

This paper presents the water absorption and strength properties of short carbon fiber reinforced mortar (CFRM) composite. Four CFRM composites with 1%, 2%, 3%, and 4% short pitch-based carbon fibers were produced in this study. Normal Portland cement mortar (NCPM) was also prepared for use as the control mortar. The freshly mixed mortar composites were tested for workability, wet density, and entrapped air content. In addition, the hardened mortar composites were examined for compressive strength, splitting tensile strength, flexural strength, and water absorption at the ages of 7 and 28 days. The effects of different carbon fiber contents on the tested properties were observed. Test results showed that the incorporation of carbon fibers decreased the workability and wet density, but increased the entrapped air content in mortar composite. Most interestingly, the compressive strength of CFRM composite increased up to 3% carbon fiber content and then it declined significantly for 4% fiber content, depending on the workability and compaction of the mortar. In contrast, the splitting tensile strength and flexural strength of the CFRM composite increased for all fiber contents due to the greater cracking resistance and improved bond strength of the carbon fibers in the mortar. The presence of short pitch-based carbon fibers significantly strengthened the mortar by bridging the microcracks, resisting the propagation of these minute cracks, and impeding the growth of macrocracks. Furthermore, the water absorption of CFRM composite decreased up to 3% carbon fiber content and then it increased substantially for 4% fiber content, depending on the entrapped air content of the mortar. The overall test results suggest that the mortar with 3% carbon fibers is the optimum CFRM composite based on the tested properties.


2020 ◽  
Vol 40 (5) ◽  
pp. 415-420 ◽  
Author(s):  
Yasin Altin ◽  
Hazal Yilmaz ◽  
Omer Faruk Unsal ◽  
Ayse Celik Bedeloglu

AbstractThe interfacial interaction between the fiber and matrix is the most important factor which influences the performance of the carbon fiber-epoxy composites. In this study, the graphitic surface of the carbon fibers was modified with graphene oxide nanomaterials by using a spray coating technique which is an easy, cheap, and quick method. The carbon fiber-reinforced epoxy matrix composites were prepared by hand layup technique using neat carbon fibers and 0.5, 1 and 2% by weight graphene oxide (GO) modified carbon fibers. As a result of SEM analysis, it was observed that GO particles were homogeneously coated on the surface of the carbon fibers. Furthermore, Young's modulus increased from 35.14 to 43.40 GPa, tensile strength increased from 436 to 672 MPa, and the elongation at break was maintained around 2% even in only 2% GO addition.


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