Structure of non-ordered regions in linear polyethylene lamellae

Promising aspects of the structural modification of polymers and polymer composites with the aid of high pressures

“…Figure 12 presents the dependence of the degree of crystallinity of SHMPE specimens on the draw ratio, obtained from X-ray data (K x ) and from density measurements (K d ). 162 Evidently the absolute values of the X-ray degree of crystallinity are smaller than those found from the measurements of r. The observed difference between the values of K x and K d agrees with the available literature data 163,164 and can have two explanations.…”

“…According to Egorov et al, 163 X-ray diffraction analysis yields the so called `geometrical' degree of crystallinity, because the macromolecules arranged parallel to one another but without a threedimensional order are detected by this method as disordered regions. On the other hand, in dilatometric measurements they can contribute to the crystalline phase.…”

“…It is therefore used to determine a or . The parameter DK may be treated as the decrease in the fraction of oriented macromolecules in the noncrystalline regions 163 or in the volume of the interfacial regions. 164 Comparison of the data presented in Fig.…”

Morphological Consequences of Interchange Reactions during Solid State Polymerization in Oriented Polymers

“…It consists of the set of chains that emanate from opposite faces of two crystals. The area of each face is taken to be (50 Å) 2 , with 100 chains emanating from each face. Intercrystalline wall distances of 30, 50, 70, 100, and 120 Å have been considered in this work.…”

“…There have been a few attempts to experimentally quantify the different topological chains in the noncrystalline regions of oriented polymers. , There is also abundant theoretical work on the thermodynamic equilibrium in semicrystalline structures. These have used free energy minimization, ,− or the Gambler's ruin approach, with either a random walk model − or an RIS scheme .…”