Ultra-Drawing and the Resultant Structure and Properties of Poly(acrylonitrile) and Its Copolymers with Different Thermal Stabilities
Daisuke Sawai, Yuya Fujii, Kazuto Hatakeyama, Tetsuo Kanamoto
Department of Applied Chemistry, Tokyo University of Science
JAPAN

Keywords: Poly(acrylonitrile), Acrylonitrile Copolymers , Ultra-Drawing

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A two-stage draw technique, consisting of the initial solid-state coextrusion followed by the second-stage tensile drawing, was applied for ultradrawing of three acrylic polymers with different thermal stabilities, i.e. poly(acrylonitrile) (PAN) and two copolymers of acrylonitrile with methyl methacrylate (AN/MA) or methacrylic acid (AN/MAA). Although optimum draw temperatures for the second-stage draw were 170-180°C for all of the three polymers, the maximum achieved total draw ratios (DRt) were ~70 for PAN and AN/MA and ~45 for thermally less stable AN/MAA. Thus, the highest achieved chain orientation function fc = 0.988 for AN/MAA was significantly lower than fc = 0.995 for the other two polymers. It is noted, however, that the fc value achieved for AN/MAA was significantly higher than the highest fc value of ~0.97 previously reported for tensile drawing of a PAN fiber. These facts indicate that the two-stage draw technique is an excellent technique for achieving higher draw and chain orientation. The highest tensile modulus and strength were obtained by drawing of AN/MA; the values were 24 and 1.3 GPa, respectively.