2002 Volume 59 Issue 5 Pages 274-280
A two-stage draw technique, consisting of the initial solid-state coextrusion followed by the second-stage tensile drawing, was applied. for ultradrawing ofthree 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.
