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>A comparison of the dielectric method with density, moisture regain, and x‐ray diffraction methods of determining fine structure in cellulosic materials
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A comparison of the dielectric method with density, moisture regain, and x‐ray diffraction methods of determining fine structure in cellulosic materials
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机译：A comparison of the dielectric method with density, moisture regain, and x‐ray diffraction methods of determining fine structure in cellulosic materials
AbstractA comparison between the dielectric method and density, moisture regain, and x‐ray diffraction methods of estimating crystallinity in cellulosic materials is presented. The merits of the dielectric method compared to the other methods are discussed. Although the permittivities of completely crystalline and completely noncrystalline celluloses are not directly measureable, the use of extrapolated values for completely crystalline and completely noncrystalline celluloses make it possible to assign a percentage crystallinity to a given material from a single permittivity measurement. Capacitance measurements are very sensitive, accurate, and rapid. Therefore, the dielectric method is capable of following small and rapid changes in crystalline content arising from mechanical, chemical, or thermal treatments. In such a study, permittivities of completely crystalline and completely noncrystalline celluloses are not required. Since the relationship between permittivity and crystallinity is linear, it appears reasonable to continue to represent the fine structure of a cellulosic material by a simple model of a mixture or two hyprothetical components: “crystalline” and “noncrystalline” cellulose and to retain the concept of “percentage crystallinity” in its
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