Study on the Crystallization Behavior of PAN Fibers during Hot-Drawing Process in Supercritical Carbon Dioxide Fluid with Different Strain

2020 ◽  
Vol 976 ◽  
pp. 84-89
Author(s):  
Meng Meng Qiao ◽  
Hai Juan Kong ◽  
Xiao Ma Ding ◽  
Zhi Feng Hu ◽  
Mu Huo Yu
Keyword(s):  
Mechanical Properties ◽  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Carbon Fibers ◽  
Crystallization Behavior ◽  
Strength Analysis ◽  
Drawing Process ◽  
Hot Drawing ◽  
Pan Fibers ◽  
Supercritical Carbon

Hot-drawing of polyacrylonitrile (PAN) fibers is an important step in the production of carbon fibers. In this article, we investigated the effect of strain on the crystallization behavior and mechanical properties of PAN fibers treated in supercritical carbon dioxide (Sc-CO2) fluid. We mainly used the methods of X-ray diffraction (XRD), monofilament strength analysis and differential scanning calorimeter (DSC) to study the crystallization behavior, mechanical properties and thermal behavior of PAN fibers during hot-drawing process. The experimental results showed that the crystallinity and mechanical properties of PAN fibers both increased a lot under the action of strain during hot-drawing in Sc-CO2 fluid. This provides an important method for preparation of higher performance PAN precursor for PAN-based carbon fibers.

scholarly journals Effect of Different Pressures of Supercritical Carbon Dioxide on the Microstructure of PAN Fibers during the Hot-Drawing Process

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 403 ◽  
Author(s):  
Mengmeng Qiao ◽  
Haijuan Kong ◽  
Xiaoma Ding ◽  
Zhifeng Hu ◽  
Luwei Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Strength Analysis ◽  
Drawing Process ◽  
X Ray ◽  
Degree Of Orientation ◽  
Hot Drawing ◽  
Pan Fibers ◽  
Supercritical Carbon

The hot-drawing process of polyacrylonitrile (PAN) fibers is an important step during the production of PAN-based carbon fibers. In this study, supercritical carbon dioxide (Sc-CO2) was used as one kind of media for thermal stretching of PAN fibers to study the effect of different pressures of Sc-CO2 on crystallinity, degree of orientation and mechanical property of PAN fibers during the hot-drawing process. The changes of microstructure and mechanical properties in the PAN fibers were investigated by wide-angle X-ray diffraction, small angle X-ray scattering and monofilament strength analysis. The results showed that as the pressure increased, the crystallinity and degree of orientation of PAN fibers increased. Furthermore, when the pressure was 10 MPa, the crystallinity increased from 69.78% to 79.99%, which was the maximum crystallinity among the different pressures. However, when the pressure was further increased, the crystallinity and degree of orientation of the fibers were reduced. The test results of the mechanical properties were consistent with the trends of crystallinity and degree of orientation, showing that when the pressure was 10 MPa, the tensile strength of the fibers increased from 4.59 cN·dtex−1 to 7.06 cN·dtex−1 and the modulus increased from 101.54 cN·dtex−1 to 129.55 cN·dtex−1.

scholarly journals Study on Crystallization Behaviors and Properties of F-III Fibers during Hot Drawing in Supercritical Carbon Dioxide

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 856 ◽  
Author(s):  
Xiaoma Ding ◽  
Haijuan Kong ◽  
Mengmeng Qiao ◽  
Zhifeng Hu ◽  
Muhuo Yu
Keyword(s):  
Mechanical Properties ◽  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Treatment Time ◽  
Orientation Factor ◽  
X Ray ◽  
X Ray Scattering ◽  
Hot Drawing ◽  
Supercritical Carbon ◽  
Ray Scattering

In order to obtain F-III fibers with high mechanical properties, pristine F-III fibers were hot drawn at the temperature of 250 °C, pressure of 14 MPa, tension of 6 g·d−1, and different times, which were 15 min, 30 min, 45 min, 60 min, 75 min, 90 min, and 105 min, respectively, in supercritical carbon dioxide (Sc-CO2) in this article. All the samples, including the pristine and treated F-III fibers, were characterized by a mechanical performance tester, wide-angle X-ray scattering (WAXS), small-angle X-ray scattering (SAXS), and thermogravimetric analysis (TGA). The results showed that the thermal stability of F-III fibers was enhanced to some extent, and the tensile strength and modulus of F-III fibers had great changes as the extension of treatment time during hot drawing in Sc-CO2, although the treatment temperature was lower than the glass transition temperature (Tg) of F-III fibers. Accordingly, the phase fraction, orientation factor fc of the (110) crystal plane, fibril length lf, and misorientation angle Bφ of all the samples were also investigated. Fortunately, the hot drawing in Sc-CO2 was successfully applied to the preparation of F-III fibers with high mechanical properties.

Enhancement of the Mechanical Properties of PEBAX Graphene Nanocomposite Using Supercritical Fluid Assisted Extrusion Polymer Processing Technique

2017 ◽  
Vol 883 ◽  
pp. 75-84 ◽  
Author(s):  
Nireeksha Karode ◽  
Laurence Fitzhenry ◽  
Siobhán Matthews ◽  
Philip Walsh ◽  
Austin Coffey
Keyword(s):  
Mechanical Properties ◽  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Mechanical Performance ◽  
Mechanical Analysis ◽  
Polymer Processing ◽  
Processing Technique ◽  
Graphene Nanocomposites ◽  
Mechanical Tensile ◽  
Supercritical Carbon

Medical tubing used in minimally invasive devices presents a number of design considerations depending on the material used, design requirements (such as sufficient stiffness, flexibility and biocompatibility) and processing conditions. Currently, manufacturing industries adopt co-extrusion systems to meet design specifications, by using multilayer configuration leading to higher cost per device and increased complexity. This paper investigates the mechanical performance of nanocomposites using supercritical carbon dioxide assisted polymer processing technique. The use of innovative medical compounds such as PEBAX graphene nanocomposites have resulted in measurable improvements in mechanical properties. This study also presents the effect of supercritical carbon dioxide on the mechanical and physical properties of the polymer matrix. The mechanical properties have been investigated using dynamic mechanical analysis (DMA) and mechanical tensile test, where sufficient reinforcement was observed depending on the composition of graphene within PEBAX matrix. ATR-FTIR was used to further analyze the effect of supercritical carbon dioxide and interactions within the polymer composite matrix.

Effects of Supercritical Carbon Dioxide on Interfacial Properties of Carbon Fiber

2012 ◽  
Vol 535-537 ◽  
pp. 2577-2584
Author(s):  
Kui Liu ◽  
Ling Hui Meng ◽  
Jing Cheng Zeng ◽  
Xue Bin Feng
Keyword(s):  
Carbon Dioxide ◽  
Carbon Fiber ◽  
Supercritical Carbon Dioxide ◽  
Carbon Fibers ◽  
Interfacial Properties ◽  
Treatment Method ◽  
Treated Carbon ◽  
Lower Temperature ◽  
Carbon Fiber Epoxy ◽  
Supercritical Carbon

In this paper , a new treatment method based on polyacrylonitrile (PAN) based carbon fiber treated by supercritical carbon dioxide (SCCO2) is proposed. This method aiming to obtain a controlled interface is green and pollutionless . The surface state of carbon fibers both untreated and treated on different temperature was studied by using SEM, AFM and XPS. The results show that SCCO2 can erode the surface of carbon fibers. Roughness of modified carbon fiber is higher than that of the untreated. Interfacial properties of the treated carbon fiber /epoxy microcomposites were improved. Interfacial shear strength (ILSS) of CFRP shows that treated carbon fiber /epoxy at a lower temperature can be increased by 17.35%, which means that an effect of optimized interface is obtained.

Mechanical properties of microcellular and nanocellular silicone rubber foams obtained by supercritical carbon dioxide

2019 ◽  
Vol 51 (6) ◽  
pp. 559-568 ◽  
Author(s):  
Bin Xiang ◽  
Yalan Jia ◽  
Yajie Lei ◽  
Fengshun Zhang ◽  
Jiangping He ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Silicone Rubber ◽  
Supercritical Carbon

scholarly journals Time-Dependence of Mechanical Property Alterations on Anthracite Coals Treated by Supercritical Carbon Dioxide

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Wei Li ◽  
Bin Pang ◽  
Er-lei Su ◽  
Quanlin Yang ◽  
Qingquan Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Time Dependence ◽  
Coal Mass ◽  
Stress Constraint ◽  
Physical Chemical ◽  
Anthracite Coal ◽  
Triaxial Compressive Strength ◽  
Supercritical Carbon

The injection of supercritical carbon dioxide (Sc-CO2) into coal seams remarkably changes the physical-chemical structures of coal mass and thereby improves coal mechanical properties. In this study, a series of unconfined and triaxial compressive strength tests were performed on anthracite coal samples under the pressure of 8 MPa at the temperature of 35°C for 24 h and 48 h, respectively. Besides, experiments with longer Sc-CO2 treatment time were carried out on coal mass without stress constraint to observe the damage mode of coal. The results show that Sc-CO2 treatment obviously alters time-dependent mechanical properties of anthracite coal. The coal samples treated with Sc-CO2 for 240 h and 960 h show different damage modes from limited fractures to a complicated fracture network. The time-dependence of the mechanical weakening model on Sc-CO2-treated coal was proposed to explain the link between CO2 flow and mechanical weakening effect by means of physical-chemical effects on time scales.

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