Crystalline-amorphous features significance

Miscibility or compatibility provided by the compatibilizer or TLCP itself can affect the dimensional stability of in situ composites. The feature of ultra-high modulus and low viscosity melt of a nematic liquid crystalline polymer is suitable to induce greater dimensional stability in the composites. For drawn amorphous polymers, if the formed articles are exposed to sufficiently high temperatures, the extended chains are retracted by the entropic driving force of the stretched backbone, similar to the contraction of the stretched rubber network [61,62]. The presence of filler in the extruded articles significantly reduces the total extent of recoil. This can be attributed to the orientation of the fibers in the direction of drawing, which may act as a constraint for a certain amount of polymeric material surrounding them. 

Peak maxima are observed near 2930 and 2890 cm-1. CH stretching features for fatty compounds (and proteins) and carbohydrates are significantly different. More bands are observed for crystalline simple sugars, than complex, amorphous, or fully hydrated carbohydrates. 

The disorder of the atomic structure is the main feature which distinguishes amorphous from crystalline materials. It is of particular significance in semiconductors, because the periodicity of the atomic structure is central to the theory of crystalline semiconductors. Bloch s theorem is a direct consequence of the periodicity and describes the electrons and holes by wavefunctions which are extended in space with quantum states defined by the momentum. The theory of lattice vibrations has a similar basis in the lattice symmetry. The absence of an ordered atomic structure in amorphous semiconductors necessitates a different theoretical approach. The description of these materials is developed instead from the chemical bonding between the atom, with emphasis on the short range bonding interactions rather than the long range order. 

In the following, we compare the spectra of the corresponding amorphous and crystalline materials. In this connection another feature is significant, the shift of absorption which may occur in either direction. Going from the crystal to the amorphous material, this shift is towards smaller energies in Ge, Si and 111—V compounds, and in the opposite direction in Se and Te. 

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