Amorphous material/polymers/regions oriented

Noncrystalline or amorphous materials produce patterns with only a few diffuse maxima, which may be either broad rings or arcs if the amorphous regions are partially oriented [3]. Synthetic polymers, which are branched or cross-linked, are usually amorphous, as are linear polymers with bulky side groups, which are not spaced in a stereoregular manner along the backbone [3]. 

Orientation, as well as crystallinity, affects the barrier properties of polymers. During orientation, in a crystalline material, the crystalline lamellae are realigned in the orientation direction, and the molecular chains in the amorphous regions are also realigned. This has two consequences. Eirst, the chain separation in the amorphous regions is decreased, increasing the intermolecular attractions and resulting in decreased chain mobility. Second, the rotation of the crystallites in the... 

Characterization of polymer orientation is most often accomplished via X-ray techniques which are suited to crystalline and paracrystalline regions (i-d). However, semicrystalline polymers present a complex system of crystalline, amorphous, and intermediate pluses ( -d) and complete characterization of semicrystalline polymers can only be achieved by application of a variety of techniques sensitive to particular aspects of orientation. As discussed by Desper (4), one must determine the degree of orientation of the individual phases in semicrystalline polymers in order to develop an understanding of structure-property relationships. Although the amorphous regions of oriented and unoriented semicrystalline polymers are primarily responsible for the environmental stress cracking behaviour and transport properties of the polymers, few techniques are available to examine the state of the amorphous material at the submicroscopic level. 

Birefringent samples have a refractive index that depends on the direction of the electric field in the light. They may be single crystals, or polycrystalline or amorphous polymers with oriented regions [23, 69]. Materials containing... 

The properties of a semicrystalline polymer are controlled by its degree of crystallinity, the alignment of crystallites relative to one another, the number and type of links between the crystallites and amorphous regions, and the overall orientation of molecules within the material. 

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