Peculiarities of the Fine Structure of PET Fibers and the Relationship to Their Basic Physical Properties

PET fibers in final form are semi-crystalline polymeric objects of an axial orientation of structural elements, characterized by the rotational symmetry of their location in relation to the geometrical axis of the fiber. The semi-crystalline character manifests itself in the occurrence of three qualitatively different polymeric phases: crystalline phase, intermediate phase (the so-called mesophase), and amorphous phase. When considering the fine structure, attention should be paid to its three fundamental aspects: morphological structure, in other words, super-or suprastructure; microstructure; and preferred orientation.