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  • 1
    Electronic Resource
    Electronic Resource
    Physical properties of poly(vinyl alcohol) fibers prepared from wet spinning/multi-step drawing (1994)
    Springer
    Journal of polymer research 1 (1994), S. 215-219 
    Details
    ISSN: 1572-8935
    Keywords: Poly(vinyl alcohol) ; Wet Spinning ; Multi-step drawing ; Wide angle X-ray diffraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The preparation of poly(vinyl alcohol) (PVA) fibers by multi-step drawing was examined. The high draw ratio was attained when the drawing just before melting point was repeated. The influences of the draw ratio on mechanical and thermal properties of the fibers were studied. We utilized the wide angle x-ray diffraction (WAXD) as a medium to observe the erystallinity and the orientation of PVA fibers to study their effects on the physical properties of the fibers. With various coagulation bath concentration, both the tenacity and Young's modulus of fibers would increase as the draw ratios increased, the elongation would decrease at the same time. The tenacity was able to reach 41.0 cN/tex with the Young's modulus being 856.2 cN/tex; also, as the draw ratios increased, both crystallinity and orientation would increase. The crystallinity was about 67.2 % and the orientation was about 86.4%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01374098
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  • 2
    Electronic Resource
    Electronic Resource
    Characterization of PAN precursor modified with potassium permanganate (1988)
    Springer
    Journal of materials science 7 (1988), S. 628-630 
    Details
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01730316
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  • 3
    Electronic Resource
    Electronic Resource
    The study of polyacrylonitrile-based activated carbon fibres for water purification: Part I (1992)
    Springer
    Journal of materials science 11 (1992), S. 6-8 
    Details
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00720764
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  • 4
    Electronic Resource
    Electronic Resource
    The effect of the distribution of composition among chains on the properties of polyacrylonitrile precursor for carbon fibre (1991)
    Springer
    Journal of materials science 26 (1991), S. 3996-4000 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Co-monomers were introduced at a controlled rate into the reaction vessel in order to control the distribution of composition among the polymeric chains. When acrylate co-monomer, such as methyl acrylate or 2-ethyl hexyl acrylate was slowly fed into the reactor, the reaction time required for copolymerization to reach a fixed conversion was not affected, and the cycling temperature (or the temperature at the onset of the exotherm) during oxidation for polyacrylonitrile (PAN) precursor was slightly shifted to a higher temperature. On the other hand, as itaconic acid (IA) co-monomer was slowly fed into the reactor, the reaction rate of copolymerization was increased, and the cycling temperature could be depressed to a lower temperature due to the IA co-monomer being able to initiate the cycling of the CN groups. The structures (such as crystallinity, crystal size, orientation) and mechanical properties for PAN precursor and its resulting carbon fibre were influenced by the distribution of composition among the chains.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02402939
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  • 5
    Electronic Resource
    Electronic Resource
    The effect of the distribution of composition among chains on the properties of polyacrylonitrile precursor for carbon fibre (1991)
    Springer
    Journal of materials science 26 (1991), S. 3996-4000 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Co-monomers were introduced at a controlled rate into the reaction vessel in order to control the distribution of composition among the polymeric chains. When acrylate co-monomer, such as methyl acrylate or 2-ethyl hexyl acrylate was slowly fed into the reactor, the reaction time required for copolymerization to reach a fixed conversion was not affected, and the cycling temperature (or the temperature at the onset of the exotherm) during oxidation for polyacrylonitrile (PAN) precursor was slightly shifted to a higher temperature. On the other hand, as itaconic acid (IA) co-monomer was slowly fed into the reactor, the reaction rate of copolymerization was increased, and the cycling temperature could be depressed to a lower temperature due to the IA co-monomer being able to initiate the cycling of the CN groups. The structures (such as crystallinity, crystal size, orientation) and mechanical properties for PAN precursor and its resulting carbon fibre were influenced by the distribution of composition among the chains.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00553481
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  • 6
    Electronic Resource
    Electronic Resource
    The effect of molecular weight on the cross section and properties of polyacrylonitrile precursor and resulting carbon fiber (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 42 (1991), S. 3045-3050 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: In this study, we investigated the effect of molecular weight in the range 1.65-4.29 × 105 (Mw) on the cross section, surface, thermal, and mechanical properties of polyacrylonitrile (PAN) precursor and its resulting carbon fiber. From the results, it can be seen that the molecular weight, with the same solid content of polymer, changes from 1.65 × 105 to 4.29 × 105 and the cross section of PAN precursor changes from a circular shape with no notable grooves surface to a been shape with a surface containing deep and straight grooves. PAN precursor with higher molecular weight has a higher onset of exothermic temperature and a higher peak temperature, but has a higher aromatization index (AI value) due to its thin and flat cross section, which causes rapid cyclization during oxidation. An increase in molecular weight results in an increase in crystal size and preferred orientation and a decrease in average pore diameter. This decrease can improve the mechanical properties of PAN precursor and its resulting carbon fiber.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1991.070421124
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  • 7
    Electronic Resource
    Electronic Resource
    Effect of comonomer composition on the properties of polyacrylonitrile precursor and resulting carbon fiber (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 43 (1991), S. 679-685 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Since the itaconic acid (IA) comonomer is the potential initiator of cyclization, therefore the introduction of IA comonomer into polyacrylonitrile (PAN) precursor can depress the onset of exotherm (or cyclized temperature) and peak temperature. However, the more the IA content, the lower the conversion of acrylonitrile (AN) in the polymerization reaction. Although 2-ethylhexyl acrylate (2-EHA) comonomer in PAN precursor may prevent the cyclization propagation of nitrile groups during oxidation, PAN precursor with a few percent of 2-EHA comonomer has a more preferred orientation. As the content of 2-EHA comonomer further increases, the orientation of the resulting carbon fiber decreases correspondingly.In this study, PAN precursor, with the composition of 98 mol % AN, 1.5 mol % 2-EHA, and 0.5 mol % IA, and its resulting carbon fiber have the best mechanical properties. From the results, it is shown that there is a good relationship between the tenacity and modulus of PAN precursor and those of its resulting carbon fiber.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1991.070430405
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  • 8
    Electronic Resource
    Electronic Resource
    The effect of the side chain of acrylate comonomers on the orientation, pore-size distribution, and properties of polyacrylonitrile precursor and resulting carbon fiber (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 42 (1991), S. 3039-3044 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The side-chain size of acrylate comonomer in polyacrylonitrile (PAN) precursor markedly influences the microstructure of PAN fiber and its resulting carbon fiber. In this paper, we propose that the model of the crystal orientation of PAN precursor and its resulting carbon fiber can explain the effect of the side-chain size of acrylate comonomer on the orientation of PAN fiber and carbon fiber. When PAN precursor contains a larger side chain of comonomer, PAN precursor has the preferred crystal orientation and higher crystallinity and the orientation of its resulting carbon fiber unexpectedly decreases. This is because the larger the side chain is, the lower is the orientation of the amorphous region of PAN fiber; as a result, the average orientation after carbonization decreases. In the same mole fraction of comonomer, the carbon fiber based on PAN precursor with a smaller side chain of acrylate comonomer has better mechanical properties and higher yield.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1991.070421123
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  • 9
    Electronic Resource
    Electronic Resource
    Thermal stabilization of polyacrylonitrile fibers (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 35 (1988), S. 631-640 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Polyacrylonitrile (PAN) fibers pretreated with potassium permanganate have reduced the activation energy of cyclization and the oxidation time, and also improved the properties of the resultant carbon fibers. The activation energy of cyclization is reduced to 24 ± 1 kcal/mol from 30 ± 3 kcal/mol and the tensile strength of the carbon fibers increases by about 20-40%. The method of measuring the “aromatization index” (AI) value is modified and is recommended in checking the oxidation process. All fully stabilized PAN fibers have almost the same AI value. However, the oxidation time is decreases by 30 min when oxidation temperature is raised by 10°C.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1988.070350306
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  • 10
    Electronic Resource
    Electronic Resource
    The microstructure of stabilized fibers (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 35 (1988), S. 863-874 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The morphology and microstructure of a stabilized fiber, nonburning fiber, has been investigated under optical and electron microscopes, and a model for the structure of the stabilized fiber is presented. Skin-core morphology was found in the cross section of the stabilized fiber. The proposed model is consistent with the lamellar-plate-like structure, measuring about 400-700 Å in thickness, 500-4000 Å in breadth and 0.1-0.5 μ m in length along the fiber axis, which is composed of microfibrils. The structure has some circumferential distribution in the outer zone, while the inner zone has a radical distribution. Evidence for the lamellar-plate structure, including two chemical structures and having two different crystalline phases, which are the original AN units and the ladder polymer, were obtained from electron microscopy, wide-angle X-ray, and electron diffraction analyses.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1988.070350402
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