Modified Vonk's Method to Determine Crystallinity and Crystal Distortion in Polymers |
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Authors: | Tsutomu Asano Shota Sano Toshihiko Okabe Takumi Sano Chie Sawatari |
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Institution: | 1. Department of Physics, Fac. of Science, Shizuoka University (emeritus professor), Suruga-ku, Shizuoka, Japan;2. Department of Chemistry, School of Education, Shizuoka University, Suruga-ku, Shizuoka, Japan;3. Department of Chemistry, Graduate School of Science and Technology, Shizuoka University, Suruga-ku, Shizuoka, Japan |
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Abstract: | Using a modified method developed from Vonk's method, detailed values of crystallinity and crystal disorder were obtained by wide angle X-ray diffraction (WAXD). In Vonk's method, the crystallinity (w) is determined by extrapolation of the WAXD experimental curve back to zero scattering angle, while the distortion factor (k) is determined by the inclination of the experimental curve at zero scattering angle. In our new method, both w and k are determined at the same time by using the least squares method. In order to show the efficiency of our method, the new fitting procedure was applied to the experimental values of polyethylene and polyethylene terephthalate as measured by Vonk, and the values of w and k determined by our new method were compared with those found by Vonk's method. The new fitting method has the advantage that it uses the whole experimental curve. Moreover, our modified Vonk's method enables us to discuss crystal distortions as arising from first-kind (thermal) disorder and second-kind (paracrystalline) disorder. |
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Keywords: | Crystal distortion modified vonk's method polymer crystallinity polyethylene polyethylene terephthalate wide angle X-ray diffraction |
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