degree of crystallinity

of a polymer
The fractional amount of @[email protected] in the polymer sample (\(w_{c}\) for @[email protected]; \(\psi_{c}\) for @[email protected]).
  1. The assumption is made that the sample can be subdivided into a crystalline phase and an amorphous phase (the so-called two-phase model).
  2. Both phases are assumed to have properties identical with those of their ideal states, with no influence of interfaces.
  3. The degree of @[email protected] may be expressed either as the @[email protected] or as the @[email protected], the two quantities being related by \(w_{c} = \frac{\psi_{c}\rho_{c}}{\rho}\) where \(\rho\) and \(\rho_{c}\) are the densities of the entire sample and of the crystalline fraction, respectively.
  4. The degree of @[email protected] can be determined by several experimental techniques; among the most commonly used are: (i) X-ray @[email protected], (ii) @[email protected], (iii) density measurements, and (iv) @[email protected] @[email protected] (IR). Imperfections in crystals are not easily distinguished from the amorphous phase. Also, the various techniques may be affected to different extents by imperfections and interfacial effects. Hence, some disagreement among the results of quantitative measurements of @[email protected] by different methods is frequently encountered.
Purple Book, 1st ed., p. 75 [Terms] [Book]