scholarly journals Influence of boric acid on radial structure of oxidized polyacrylonitrile fibers

e-Polymers ◽  
2019 ◽  
Vol 19 (1) ◽  
pp. 79-86
Author(s):  
Xue-Fei Wang ◽  
Xiao-Long Zhu ◽  
Chi Jiang ◽  
Jian-Min Guan ◽  
Xin Qian ◽  
...  
Keyword(s):  
Boric Acid ◽  
Carbon Fibers ◽  
High Performance ◽  
Boron Content ◽  
Fiber Surface ◽  
Thermal Stabilization ◽  
Stabilization Time ◽  
Radial Structure ◽  
Stabilization Temperature ◽  
Pan Fibers

AbstractThe surface modification of polyacrylonitrile (PAN) fibers with boric acid was utilized to modulate the homogeneity of the radial structure of the PAN fibers during thermal stabilization. Exothermic peaks of the fibers were put off by boric acid, and unreacted nitrile groups of the oxidized PAN fibers increased with the boron content, indicating that boric acid on the fiber surface had an retardant effect on the thermal stabilization of PAN fibers. The relative skin thicknesses of the oxidized PAN fibers were quantitatively measured by sulfuric acid etching and SEM observation. The value increased obviously with the boron content, which could be further elevated by increasing stabilization time or decreasing stabilization temperature. Oxidized PAN fibers with more homogeneous radial structure can thus be obtained with the modification of boric acid, which might be beneficial for the preparation of high performance carbon fibers.

scholarly journals Rapid and Continuous Preparation of Polyacrylonitrile-Based Carbon Fibers with Electron-Beam Irradiation Pretreatment

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1270 ◽  
Author(s):  
Jia Yang ◽  
Yuchen Liu ◽  
Jie Liu ◽  
Zhigang Shen ◽  
Jieying Liang ◽  
...  
Keyword(s):  
Electron Beam ◽  
Carbon Fibers ◽  
Thermal Stabilization ◽  
Beam Irradiation ◽  
Stabilization Time ◽  
Continuous Preparation ◽  
Energy Consuming ◽  
Time Savings ◽  
Time And Energy ◽  
Pan Fibers

Thermal stabilization is a critical, yet time- and energy-consuming process during the preparation of PAN-based carbon fibers. In this work, automobile-grade carbon fibers with a 2.85 GPa tensile strength and a 203 GPa modulus are continuously produced with electron-beam (e-beam) irradiation pretreatment and 24 min thermal stabilization. Thermal and structural analyses reveal that e-beam irradiation can lower the onset temperature of the cyclization reaction and mitigate the heat release. Meanwhile, during the process of stabilization, e-beam irradiation can facilitate the evolution of both the chemical structure and the crystalline structure of polyacrylonitrile (PAN) fibers. Comparing to the industrial production of carbon fiber with a 40 min stabilization time, e-beam irradiated PAN fibers can achieve the same degree of stabilization with a 40% time savings.

Effect of Heat Treatment on Mechanical Properties of Laminated Carbon Fiber Reinforced Polymeric Composites

2016 ◽  
Author(s):  
A. B. M. I. Islam ◽  
Ajit D. Kelkar ◽  
Lifeng Zhang
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Carbon Fiber ◽  
Carbon Fibers ◽  
Fiber Surface ◽  
Fiber Reinforced ◽  
Carbon Fabric ◽  
Carbon Fiber Reinforced ◽  
Fiber Deposition ◽  
Pan Fibers

In recent years use of electrospun nanofibers and nanoparticles to improve the interlaminar properties have increased significantly. In most of the cases the additional interlaminar phase of nanofibers is required to go through various thermal and/or chemical processes. There has been emphasis to optimize the interlaminar nanofiber layers to achieve the optimum desired mechanical properties such as interlaminar strength. One common practice is to disperse nanofibers into the resin and then use the nanofiber enhanced resin to fabricate the laminated composites. However, proper dispersion and fiber filtering out are some of the problems that exist in fabrication using the nanofiber mixed resin approach. To alleviate this problem, an innovative approach of growing PAN (polyacrylnitrile) nano fibers directly on carbon fabric by electrospinning seems to solve the dispersion and fiber filtering problem. However, as PAN fibers require stabilization and carbonization, it is obvious that carbon fabric with PAN fiber deposition will have to undergo stabilization and carbonization process. The effect of stabilization and carbonization heat treatment on the mechanical properties of carbon fiber fabric is not yet fully understood. This paper presents the effects of heat treatment on carbon fabric used for fabricating laminated carbon fiber reinforced composite with epoxy resin. The heat treatment was performed at 280°C in air for six hours, and 1200°C for one hour in nitrogen which are similar to stabilization and carbonization of pure PAN fibers. The effects, due to heat treatment, were mainly characterized in terms of mechanical properties by performing tensile tests and shear tests. Fiber surface topography was observed by SEM to analyze physical changes. Chemical changes, corresponding to the existing groups with carbon fibers, were examined through FTIR. The results obtained are compared with a set of control laminated composite specimens, which were fabricated using heat vacuum assisted resin transfer molding (HVARTM) process and cured at 149°C. The two sets of composite were infused with resin in a single vacuum bag to ensure that both sets of specimens have identical resin infusion and cure cycle. Laminates used for making control specimens were fabricated using carbon fabric which did not undergo any heat treatment. A change in laminate thickness for heat treated carbon fabric was observed indicating a possible bulk up of the carbon fibers due to loss of sizing compounds, which also resulted into significant change in tensile properties.

scholarly journals Mesophase Pitch-Based Carbon Fibers: Accelerated Stabilization of Pitch Fibers under Effective Plasma Irradiation-Assisted Modification

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6382
Author(s):  
Yuanshuo Peng ◽  
Ruixuan Tan ◽  
Yue Liu ◽  
Jianxiao Yang ◽  
Yanfeng Li ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Tensile Strength ◽  
Heating Rate ◽  
Carbon Fibers ◽  
High Performance ◽  
Low Cost ◽  
Tensile Modulus ◽  
Mesophase Pitch ◽  
Stabilization Time ◽  
Plasma Irradiation

Stabilization is the most complicated and time-consuming step in the manufacture of carbon fibers (CFs), which is important to prepare CFs with high performance. Accelerated stabilization was successfully demonstrated under effective plasma irradiation-assisted modification (PIM) of mesophase pitch fibers (PFs). The results showed that the PIM treatment could obviously introduce more oxygen-containing groups into PFs, which was remarkably efficient in shortening the stabilization time of PFs with a faster stabilization heating rate, as well as in preparing the corresponding CFs with higher performance. The obtained graphitized fiber (GF-5) from the PF-5 under PIM treatment of 5 min presented a higher tensile strength of 2.21 GPa, a higher tensile modulus of 502 GPa, and a higher thermal conductivity of 920 W/m·K compared to other GFs. Therefore, the accelerated stabilization of PFs by PIM treatment is an efficient strategy for developing low-cost pitch-based CFs with high performance.

Effects of Stabilization Temperature on the Chemical and the Physical Properties of Polyacrylonitrile Stabilized Fibers

2015 ◽  
Vol 1112 ◽  
pp. 402-405
Author(s):  
Norhaniza Yusof ◽  
Ahmad Fauzi Ismail ◽  
Juhana Jaafar ◽  
W.N.W. Salleh ◽  
H. Hasbullah
Keyword(s):  
Tensile Strength ◽  
Physical Properties ◽  
Carbon Fibers ◽  
Chemical Structure ◽  
Young Modulus ◽  
Precursor Fiber ◽  
Stabilization Time ◽  
Ftir Studies ◽  
Stabilization Temperature ◽  
Mechanical Strengths

The present work dealt with the preparation of carbon fibers from Polyacrylonitrile (PAN)/ acrylamide (AM) fibers via a solvent-free coagulation process. The PAN/AM fibers were stabilized in an oxidizing atmosphere at various temperatures (200, 250, 275, and 300 °C), while the stabilization time was fixed at thirty minutes. The effects of stabilization temperature on the chemical and the physical properties of the prepared stabilized fibers were studied. The chemical structure evolutions of stabilized fibers (SFs) from the precursor fiber were observed with FTIR studies, whereas the microstructure properties were thoroughly characterized with SEM studies. The mechanical strengths of the SFs were obtained from the Young Modulus and the tensile strength analyses. Stabilization temperature at 275°C had been identified as the optimum stabilization temperature for the PAN/AM fibers.

Post spinning treatment of PAN fibers using succinic acid to produce high performance carbon fibers

Carbon ◽  
1998 ◽  
Vol 36 (7-8) ◽  
pp. 893-897 ◽  
Author(s):  
J. Mittal ◽  
R.B. Mathur ◽  
O.P. Bahl ◽  
M. Inagaki
Keyword(s):  
Succinic Acid ◽  
Carbon Fibers ◽  
High Performance ◽  
Pan Fibers

scholarly journals Thermal Analysis and Crystal Structure of Poly(Acrylonitrile-Co-Itaconic Acid) Copolymers Synthesized in Water

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 221
Author(s):  
Hailong Zhang ◽  
Ling Quan ◽  
Aijun Gao ◽  
Yuping Tong ◽  
Fengjun Shi ◽  
...  
Keyword(s):  
Carbon Fibers ◽  
High Performance ◽  
Thermal Stabilization ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Air Atmosphere ◽  
Composition And Structure ◽  
Average Size ◽  
Dsc Curves

The composition and structure of polyacrylonitrile (PAN) precursors play an important role during thermal stabilization, which influences the properties of the resulting carbon fibers. In this paper, PAN homopolymer and PAN-itaconic (IA) copolymers with different IA contents were synthesized by aqueous phase precipitation polymerization. The effects of IA content on the structure and thermal properties were studied using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The morphology of PAN polymers showed that the average size of the PAN particles increased with the increase of IA content in the feed. The content of the IA comonomer on the copolymers was quantitatively characterized by the relative absorbance intensity (A1735/A2243) in FTIR spectrum. With the increase of IA content in the feed, PAN-IA copolymers exhibited lower degree of crystallinity and crystal size than the control PAN homopolymer. The results from DSC curves indicated that PAN-IA1.0 copolymers had lower initial exothermic temperature (192.4 °C) and velocity of evolving heat (6.33 J g−1 °C−1) in comparison with PAN homopolymer (Ti = 238.1 °C and ΔH/ΔT = 34.6 J g−1 °C−1) in an air atmosphere. TGA results suggested that PAN-IA1.0 copolymers had higher thermal stability than PAN homopolymer, which can form a ladder structure easier during thermal processing. Therefore, PAN-IA1.0 copolymers would be a suitable candidate for preparing high performance PAN based carbon fibers.

Development of Porous Polyacrylonitrile Composite Fibers: New Precursor Fibers with High Thermal Stability

2021 ◽  
Vol 2 (4) ◽  
pp. 454-465
Author(s):  
Ehsan Samimi-Sohrforozani ◽  
Sara Azimi ◽  
Alireza Abolhasani ◽  
Samira Malekian ◽  
Shahram Arbab ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Carbon Fibers ◽  
High Performance ◽  
Ternary Phase Diagram ◽  
Decomposition Temperature ◽  
High Thermal Stability ◽  
Composite Fibers ◽  
Porous Composite ◽  
Scanning Calorimetry ◽  
Pan Fibers

Polyacrylonitrile (PAN) fibers with unique properties are becoming increasingly important as precursors for the fabrication of carbon fibers. Here, we suggest the preparation of porous PAN composite fibers to increase the homogeneity and thermal stability of the fibers. Based on the thermodynamics of polymer solutions, the ternary phase diagram of the PAN/H2O/Dimethylformamide (DMF) system has been modeled to introduce porosity in the fibers. Adding a conscious amount of water (4.1 wt.%) as a non-solvent to the PAN solution containing 1 wt.% of graphene oxide (GO), followed by wet spinning, has led to the preparation of porous composite fibers with high thermal stability and unique physicochemical properties. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) results elucidate that PAN/GO/H2O porous composite fibers have a higher thermal decomposition temperature, increased residual weight, reduced heat release rate, and higher crystallinity in comparison with the pristine PAN fibers, being a promising precursor for the development of high-performance carbon fibers. The results show a promising application window of the synthesized PAN fibers in electronic and electrochemical devices.

scholarly journals Effect of Thermal Stabilization on PAN-Derived Electrospun Carbon Nanofibers for CO2 Capture

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4197
Author(s):  
Elisa Maruccia ◽  
Stefania Ferrari ◽  
Mattia Bartoli ◽  
Lorenzo Lucherini ◽  
Giuseppina Meligrana ◽  
...  
Keyword(s):  
Carbon Nanofibers ◽  
Co2 Capture ◽  
Carbon Capture ◽  
Thermal Stabilization ◽  
Co2 Uptake ◽  
Stabilization Temperature ◽  
Co2 Adsorption Capacity ◽  
Nitrogen Doped Carbon ◽  
Poly Acrylonitrile ◽  
Pan Fibers

Carbon capture is amongst the key emerging technologies for the mitigation of greenhouse gases (GHG) pollution. Several materials as adsorbents for CO2 and other gases are being developed, which often involve using complex and expensive fabrication techniques. In this work, we suggest a sound, easy and cheap route for the production of nitrogen-doped carbon materials for CO2 capture by pyrolysis of electrospun poly(acrylonitrile) (PAN) fibers. PAN fibers are generally processed following specific heat treatments involving up to three steps (to get complete graphitization), one of these being stabilization, during which PAN fibers are oxidized and stretched in the 200–300 °C temperature range. The effect of stabilization temperature on the chemical structure of the carbon nanofibers is investigated herein to ascertain the possible implication of incomplete conversion/condensation of nitrile groups to form pyridine moieties on the CO2 adsorption capacity. The materials were tested in the pure CO2 atmosphere at 20 °C achieving 18.3% of maximum weight increase (equivalent to an uptake of 4.16 mmol g−1), proving the effectiveness of a high stabilization temperature as route for the improvement of CO2 uptake.

scholarly journals Structure and Properties of Polysulfone Filled with Modified Twill Weave Carbon Fabrics

Polymers ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 50
Author(s):  
Dilyus I. Chukov ◽  
Sarvarkhodza G. Nematulloev ◽  
Viсtor V. Tсherdyntsev ◽  
Valerii G. Torokhov ◽  
Andrey A. Stepashkin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surface Modification ◽  
Carbon Fibers ◽  
High Performance ◽  
Fiber Surface ◽  
Polymer Matrices ◽  
Thermosetting Polymers ◽  
Chemical Inertness ◽  
Twill Weave ◽  
Carbon Fabrics

Carbon fabrics are widely used in polymer based composites. Nowadays, most of the advanced high-performance composites are based on thermosetting polymer matrices such as epoxy resin. Thermoplastics have received high attention as polymer matrices due to their low curing duration, high chemical resistance, high recyclability, and mass production capability in comparison with thermosetting polymers. In this paper, we suggest thermoplastic based composite materials reinforced with carbon fibers. Composites based on polysulfone reinforced with carbon fabrics using polymer solvent impregnation were studied. It is well known that despite the excellent mechanical properties, carbon fibers possess poor wettability and adhesion to polymers because of the fiber surface chemical inertness and smoothness. Therefore, to improve the fiber–matrix interfacial interaction, the surface modification of the carbon fibers by thermal oxidation was used. It was shown that the surface modification resulted in a noticeable change in the functional composition of the carbon fibers’ surface and increased the mechanical properties of the polysulfone based composites. Significant increase in composites mechanical properties and thermal stability as a result of carbon fiber surface modification was observed.

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