Abstract
It is shown that liquid crystal polyester can be extruded and drawn from the melt into fine fibres which possess stiffnesses up to 68 GPa. Thicker fibres with smaller draw ratios have correspondingly lower stiffnesses, which are correlated with molecular alignments characterized by flat plate X-ray diffraction. Fibres with a range of diameters were heat-treated over a range of temperatures to determine the effect of annealing on preferred orientation and stiffness. Heat-treatment of as-spun fibres produced maxima in axial stiffness at 170° C, corresponding to an increase in preferred orientation, and 270° C, corresponding to the development of quasi-crystalline order which is analysed. Scanning electron microscopy showed the existence of needle-like domains of approximately circular cross section up to 0.8 μm in diameter. These were aligned in the direction of drawing in contrast to being haphazardly arranged in a hot rolled specimen displaying no preferred orientation.
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References
D. C. Prevorsek, in “Polymer Liquid Crystals”, Ch. 12, edited by A. Ciferri, W. Krigbaum and B. Meyer (Academic Press, New York, 1982).
A. Ciferri andB. Valenti, in “Ultra High Modulus Polymers” Ch. 7, edited by A. Ciferri and I. M. Ward (Applied Science, London, 1979).
D. Acierno, F. R. La Mantia, G. Polizzotti, A. Ciferi andB. Valenti,Macromolecules 15 (1982) 1455.
K. Shimamura, J. L. White andJ. F. Fellers,J. Appl. Polym. Sci. 26 (1981) 2165.
W. J. Jackson Jr andH. F. Kuhfuss,J. Polym. Sci., Polym. Chem. Ed. 14 (1976) 2043.
H. F. Kuhfuss andW. J. Jackson Jr, U.S. Patents 3 778 410 (1973) and 3 804 805 (1974).
A. M. Donald andW. H. Windle,Polymer 25 (1984) 1235.
A. A. Bright andL. S. Singer,Carbon 17 (1979) 59.
J. C. Jenkins andG. M. Jenkins,ibid. 24 (1986) 93.
J. C. Jenkins andG. M. Jenkins, in Proceedings of the Conference on Pitch, University of Newcastle, UK, 1987 (Society of Chemical Industry, 1987) Paper 15.
H. Tharpar andM. Bevis,J. Mater. Sci. Lett. 2 (1983) 733.
A. M. Donald andA. H. Windle,J. Mater. Sci. 19 (1984) 2085.
C. J. Lewis, private communication (1986).
O. Kratky,Koll. Zh. 64 (1933) 213.
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Jenkins, J.C., Jenkins, G.M. The induction of preferred orientation in a liquid crystal co-polyester by extrusion and drawing. J Mater Sci 22, 3784–3792 (1987). https://doi.org/10.1007/BF01161495
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DOI: https://doi.org/10.1007/BF01161495