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DTIC ADA141755: Fabrication of Biaxially Oriented Films via Poly(P-... |
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by Defense Technical Information Center |
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The fundamental innovation arising from this research is |
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that the state of spatial biaxial order in lyotropic |
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Poly(p-phenylene terephthalamide)(PPTA/H2SO4 liquid |
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crystal solutions is strongly controlled by an externally |
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imposed stress field. Also the orientation only relaxes |
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slowly after the stresses are released. This enables |
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processes to b devised that develop biaxial stress on a |
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flowing liquid crystal to cause high levels of molecular |
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orientation. Since the character of the stress, i.e., the |
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magnitude and direction of the sigma ij components, is |
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set by the experimental conditions, then the orientation |
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is also controllable. Thus a process has been developed |
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which takes advantage of the rheological and phase |
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behavior of PPTA/H2SO4 to create films ranging from |
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uniaxial through unequal biaxial to equal biaxial |
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orientation. This and other structural features have been |
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documented by WAXS, pole figure analysis, microscopy and |
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SAXS. Also mechanical property studies show that a range |
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of strengths and moduli can be obtained including a film |
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of equal axial orientation (fzc = 0.45, fyc = 0.50 using |
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the White-Spruiell indices from 0.0 to 0.5 where 0.5 |
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means perfect orientation). Property values for this film |
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are modulus in the machine direction = 700,000 psi and |
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transverse direction = 800,000 psi with tensile strengths |
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in the machine direction = 25,000 psi and transverse |
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direction = 30,000 psi. |
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Date Published: 2018-01-19 12:34:36 |
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Identifier: DTIC_ADA141755 |
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Item Size: 5421714 |
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Language: english |
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Media Type: texts |
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# Topics |
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DTIC Archive; Fellers,J F ; TENNESSE... |
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@chris85 |
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