TIT# Novel Aspects in the Structure of Poly(ethylene terephthalate) As
     Revealed by Means of Small-Angle X-ray Scattering
AUT# Santa Cruz, C.; Stribeck, N.; Zachmann, H. G.; Baltà Calleja, F. J.
SOU# Macromolecules (1991), 24, 5980-5990
LOC# xv010  @selbst.ftx
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ABS# The absolute intensity of the small-angle X-ray scattering (SAXS) of
     poly(ethylene terephthalate) (PET) samples crystallized at different
     temperatures for different times was measured by means of a Kratky
     camera. The correlation function and the interface distribution function
     were calculated, and the values obtained from different methods for the
     long period L, the crystal thickness $l_c$, the thickness of the
     amorphous regions $l_a$, and the linear degree of crystallinity
     $x_{CL}$ were compared with each other. After a critical examination of
     the different methods, including model calculations of the interface
     distribution function and the correlation function, it is shown that,
     in the case of a broad distribution of the thicknesses, the interface
     distribution function gives the more reliable results for $l_c$, $l_a$,
     and L. By comparing the linear crystallinity $x_{CL}$ determined from
     SAXS with the crystallinity $x_c$ as determined from wide-angle X-ray
     scattering or from density, it is concluded that the material is not
     homogeneously filled with lamellar stacks. The coherently scattering
     lamellar stack consists of only 3-6 lamellae.