Semicrystalline polymers lamellar spacing

FIGURE 10.9 Schematic diagram of a SAXS-WAXS experiment performed on a semicrystalline polymer SAXS provides a measure of lamellar spacing, whereas the crystal structure is derived from the WAXS measurements. 

Two new parametets for describing the SAS data from semictystalline polymers are introduced. These are the ellipticity of the trace of the lamellar peak-maxima, and the orientation parameter determined from the increase in the longitudinal width of the lamellar peak with the distance from the meridional axis. These two parameters along with Ae lamellar spacing, tilt-angle of the lamellar plane, the diameter and the coherence length of the lamellar stack, and the lamellar intensity completely describe the SAS data from oriented semiciystalline polymers. These parameters can be obtained by fitting the 2-D SAS from uniaxially oriented semicrystalline polymers in elliptical coordinates. 

Polymer chains in semicrystalline polymers such as polyolefines, aliphatic polyamides (nylons), and aliphatic polyesters crystallize in the form of lamellae of folded chains that are organized to form lamellar stacks (Fig. 2.14a). The spaces between the lamellae and between the stacks are occupied by... 

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