Production and Optimization of Continuous Roving-like UTSI Pitch-based Carbon Fiber Composites PDF Download
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Author: Matthew Patrick Duran
Publisher:
ISBN:
Category :
Languages : en
Pages : 105
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Book Description
UTSI has developed a new low-cost jet-dry-spin method for the production of mesophase pitch-based carbon fibers. The objective of this preliminary study is to optimize the production of the UTSI carbon fiber composites and to better understand the surface texture between the fiber and matrix material. Several fabrication techniques were studied with varied preparation conditions to determine the effects on apparent density, electrical resistivity, tensile and flexural properties. Various polymeric resins and hardeners were used to demonstrate the versatility of the application of UTSI carbon fibers. During these investigations various analysis techniques including Scanning Electron Microscopy (SEM), x-ray diffraction, and optical microscope aided in the determination of the structural characteristics of the fiber and its composite. It was found that vacuum bagging resin infusion is the optimal fabrication process due to its ability to minimize porosity and increase fiber volume/content. The use of extra slow hardener allowed excellent control over the wetting, degassing, and cure time. Increasing applied pressure during the fabrication of the composites increases the fiber content/volume leading to improvements in mechanical properties, apparent density and electrical conductivity. However, excessive pressure causes difficult diffusion of the resin and the crash of carbon fibers which decrease the above properties. A preliminary work also shows that low cost phenolic resin composites and converted C/C composites can be easily prepared using UTSI CF. Fiber surface oxidative treatments with ozone and HNO3 solution were performed for comparison and optimization. Single-fiber fragmentation tests including single-fiber tensile/diameter testing revealed improvements in interfacial shear strength between oxidized carbon fiber (CF) and epoxy resin. Ozone treatment proved to be optimal, increasing flexure strength two-fold with respect to composites fabricated using as received CF.
Author: Matthew Patrick Duran
Publisher:
ISBN:
Category :
Languages : en
Pages : 105
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Book Description
UTSI has developed a new low-cost jet-dry-spin method for the production of mesophase pitch-based carbon fibers. The objective of this preliminary study is to optimize the production of the UTSI carbon fiber composites and to better understand the surface texture between the fiber and matrix material. Several fabrication techniques were studied with varied preparation conditions to determine the effects on apparent density, electrical resistivity, tensile and flexural properties. Various polymeric resins and hardeners were used to demonstrate the versatility of the application of UTSI carbon fibers. During these investigations various analysis techniques including Scanning Electron Microscopy (SEM), x-ray diffraction, and optical microscope aided in the determination of the structural characteristics of the fiber and its composite. It was found that vacuum bagging resin infusion is the optimal fabrication process due to its ability to minimize porosity and increase fiber volume/content. The use of extra slow hardener allowed excellent control over the wetting, degassing, and cure time. Increasing applied pressure during the fabrication of the composites increases the fiber content/volume leading to improvements in mechanical properties, apparent density and electrical conductivity. However, excessive pressure causes difficult diffusion of the resin and the crash of carbon fibers which decrease the above properties. A preliminary work also shows that low cost phenolic resin composites and converted C/C composites can be easily prepared using UTSI CF. Fiber surface oxidative treatments with ozone and HNO3 solution were performed for comparison and optimization. Single-fiber fragmentation tests including single-fiber tensile/diameter testing revealed improvements in interfacial shear strength between oxidized carbon fiber (CF) and epoxy resin. Ozone treatment proved to be optimal, increasing flexure strength two-fold with respect to composites fabricated using as received CF.
Author: Chang Liu
Publisher:
ISBN:
Category :
Languages : en
Pages : 89
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Book Description
The objective of this study is to investigate the relationship among process, structure, and property of the UTSI pitch-based carbon fibers and optimize carbon fiber's mechanical properties through the stabilization process. Various analysis techniques were employed throughout these investigations which include the Scanning Electron Microscope (SEM), optical microscope, Dia-stron system, MTS, and ImageJ. Several fiber process techniques including fiber spinning, stabilization, and carbonization were explored to determine the effect of the thermal process on the fiber yield, fiber diameter, the sheath-core structure of stabilized fibers, the pac-man and hollow core structures of carbonized fibers, and the resulting mechanical properties of the carbon fibers. It was found that stabilization time and the temperature stepping had a great deal on influence on the resulting carbon fibers. Larger diameter fiber is easy to form sheath-core structure in the stabilization process. Pac-man structure was developed at 600°C during the carbonization. Both stabilization duration and the carbonization temperature control the resulting carbon fiber diameter and fiber structure defects such as the pac-man and hollow core defects. Multi-step stabilization can reduce the total stabilization duration and improve the mechanical properties of the resulting carbon fibers. Fiber structure non-uniformities including fiber diameter distributions for a bundle fiber or along a single fiber, and pac-man angles were determined. Statistical analysis revealed the distribution of the carbon fiber cross-sectional areas and the result is compared against commercial available carbon fibers. Carbon fiber sandwiched composites (CFSCs) were fabricated with UTSI carbon fiber and commercial PAN-based carbon fibers. Several configurations of sandwich structured composites were explored to test the flexural properties with varying sandwich thickness.
Author: Viren Jayantibhai Patel
Publisher:
ISBN:
Category : Carbon fiber-reinforced plastics
Languages : en
Pages : 54
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Book Description
The purpose of this study was to manufacture and mechanically characterize low-cost carbon fiber derived from pitch-based precursor that meets or exceeds the general-purpose carbon fiber. For this study, isotropic coal-tar pitch precursor was used due to its ease in manufacturing carbon fiber and low-cost starting material. Various analyses such as elemental composition, softening point, TGA, FT-IR, NMR, single carbon fiber testing, and SEM were performed to fully characterize the precursor and carbon fiber. Using melt spinning method, the precursor was melt spun at 235 °C, a pressure of 1.5 MPa and a winding speed of 400 rpm to achieve continuous small diameter fibers known as spun/green fibers. The winding speed of the drum collector and the spinneret diameter controlled the overall diameter of the carbon fibers. The green fibers then underwent the thermal treatment processes of stabilization and carbonization. The green fibers were oxidized at 300 °C with a heating rate of 0.25 °C/min in air. Later, they were carbonized at 1100 °C with a heating rate of 1 °C/min in an inert environment. Experimentally it was determined that smaller diameter carbon fibers were easy to fully oxidize with a smaller heating rate. This also resulted in higher mechanical properties due to less defects in their structures. The isotropic pitch-based carbon fiber manufactured in this study have the maximum tensile strength and elastic modulus of 927 MPa and 86 GPa, respectively.
Author:
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Category : Fuel
Languages : en
Pages : 838
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Author:
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ISBN:
Category : Aeronautics
Languages : en
Pages : 296
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Author: Ludwig Rasper
Publisher:
ISBN:
Category : Buckets (Excavating machinery)
Languages : en
Pages : 869
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Author: Pittsburg & Midway Coal Mining Co
Publisher:
ISBN:
Category :
Languages : en
Pages : 72
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Author: United States. Employment Standards Administration
Publisher:
ISBN:
Category : Agricultural wages
Languages : en
Pages : 142
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Author:
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Category : Solar energy
Languages : en
Pages : 44
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Author: Mårten T. Landahl
Publisher: Courier Dover Publications
ISBN: 0486832775
Category : Science
Languages : en
Pages : 147
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Book Description
This classic monograph on unsteady transonic flow — the flow of air encountered at speeds at or near the speed of sound — is of continuing interest to students and professionals in aerodynamics, fluid dynamics, and other areas of applied mathematics. After a brief Introduction, Swedish physicist Mårten T. Landahl presents a chapter in which the two-dimensional solution is derived, succeeded by a discussion of its relation to the subsonic and supersonic solutions. Three chapters on low aspect ratio configurations follow, covering triangular wings and similar planforms with curved leading edges, rectangular wings, and cropped delta wings, and low aspect ratio wing-body combinations. The treatment concludes with a consideration of the experimental determination of air forces on oscillating wings at transonic speeds.
