A METHOD FOR EVALUATING STRUCTURAL DISTORTION FROM X-RAY-SCATTERING PATTERNS WITH BROAD PEAKS AND ITS APPLICATION TO THERMALLY STABILIZED ACRYLIC FIBERS

A method has been proposed for evaluating the lattice distortion that yields broad X-ray scattering peaks. The long-period structure of ther mally stabilized acrylic fibers has been analyzed by applying this met hod to the meridional small-angle X-ray scattering. The period length of the acrylic fibers increases during stabilization, while the distor tion of the period remains unchanged, maintaining a coefficient of var iation of about 0.3. It is concluded from a simulation using a model l attice that the cyclization of molecular segments proceeds faster in d isordered regions than in crystalline regions and that the cyclization in the crystalline regions proceeds preferentially from crystallites separated by smaller cyclized regions. (C) 1993 John Wiley & Sons, Inc .