Equatorial reflex

The value of the angle of tilting of the texture can be determined from the analysis of x-ray fiber diagrams. As Urbanczyk noted [18], the position of layer reflexes oil and ill or the position of equatorial reflexes 010 and 100 can be analyzed. In the first case, the tilting angle of the texture (v ) can be determined from the equation ... 

Equatorial reflexes (010), (110), (100) Meridional reflex (105) Absorption band 875 cm" Absorption band 1343 cm" Absorption band 1473 cm" ... 

The quantitative assessment of the degree of crystallite orientation by x-ray examination is not free of ambiguity. From a comparative analysis [23] in which results obtained from the consideration of (105) and from three different variations of equatorial reflection were compared, the conclusion was that the first procedure can lead to underrated results, i.e., to the underestimation of the orientation. However, it can be assumed that this does not result from an incorrect procedure, but from ignoring the fact that the adjacent (105) reflex can overlap. The absence of the plate effect of the orientation is characteristic of the orientation of crystallites in PET fibers. The evidence of this absence is the nearly identical azimuthal intensity distributions of the diffracted radiation in the reflexes originating from different families of lattice planes. The lack of the plate effect of orientation in the case of PET fiber stretching has to do with the rod mechanism of the crystallite orientation. 

X-ray patterns of smectic polymers are characterized by a series of distinct equatorial layer reflexes at small scattering angles, as is seen from Figs. 8 and 9. The presence of small angle reflexes indicates smectic order in packing of side branches, which are stacked perpendicularly or inclinely to the planes of the smectic layers formed by the backbones of macromolecules. 

In the present context the shift of the observed (h k 0)-reflexes in equatorial direction (perpendicular to tensile direction) display the transversal crystalline strain of the crystallites aligned in tensile direction... 

---