Crystalline fully/highly oriented

Fig. 8.13. Four-phase model of highly oriented semicrystalline fiber, (a) crystalline lamellae, (b) fully extended tie segments, (c) non-extended tie segments, (d) matrix (folds, ciliae, broken chains).

UHMWPE is a linear semicrystalline polymer, composed of crystalline and amorphous phases. The typical crystallinity values are in the range of 45-60%. The crystalline phase contains chains folded into highly oriented lamellae. These lamellae are oriented randomly within the amorphous phase. The lamellae are linked to each other by tie molecules. Yet, this two-phase description, fully crystalline and fully amorphous phases, has... 

In the remainder of this section, we compare EISFs and Lorentzian line widths from our simulation of a fully hydrated liquid crystalline phase DPPC bilayer at 50°C with experiments by Kdnig et al. on oriented bilayers that, in order to achieve high degrees of orientation, were not fully hydrated. We consider two sets of measurements at 60°C on the IN5 time-of-flight spectrometer at the ILL one in which the bilayer preparations contained 23% (w/w) pure D2O and another in which bilayer orientation was preserved at 30% D2O by adding NaCl. The measurements were made on samples with two different orientations with respect to the incident neutron beam to probe motions either in the plane of the bilayers or perpendicular to that plane. 

The neck is more or less fully developed and a fibrillar structure is obtained. This structure is less susceptible to degradation because of its high degree of orientation and high crystallinity. This explains the drop and then levelling off of the carbonyl content in this latter stage. 

All the highly crystalline Type I sputtered films are more or less porous, with densities of the order of 3,8 gm cm , compared with a typical value of 4.92 gm cm quoted for fully dense single crystals. Fleischauer et al pointed out that the ease with which the crystals can bend to a basal plane orientation will depend on the crystal size and the density of packing. They also suggested that an increased degree of pre-etching of the substrate would increase the number of reactive sites available for crystal formation, and therefore the density of crystal packing, as well as the... 

---