Effect of molecular orientation on the crystallization and melting behavior in poly(ethylene terephthalate)

The chemistry, manufacture and tensile behaviour of polyester fibers

“…It was found that crystallization begins at a critical amorphous orientation of 0.18 [57]. The larger increase in amorphous phase orientation is due to the strong interaction between crystallites and surrounding amorphous matrix [57]. ∑ 6000-10 000 m/min FOY (fully oriented yarn).…”

Structural development of poly(ethylene terephthalate) during uniaxial stretching above the glass‐transition temperature: Study of the statistical influence of the stretching variables

“…The effect of the level of the amorphous molecular orientation (noncrystallized samples) on T cc was reported elsewhere: it decreased toward the glass transition as f am increased. 25,59 Again, at high k st , the influence of T st on T cc was enhanced strongly. The effect of the stretching parameters on v c was similar to the previously discussed effects for Figure 5(b): a higher T st decreased the crystallinity because of the predomination of polymer chain relaxation; at high k st , this variation was enhanced (interaction effect); an increased k st increased v c .…”

“…If amorphous chains are oriented but not crystallized during the stretching process, T cc decreases toward the glass transition as f am increases. 25,61 A decrease in T cc and DH cc with respect to the as-molded PET was shown by all of the samples stretched at a lower T st (90 C; C1, C3, C5, and C7), and an opposite effect was observed for all of the samples submitted to a higher T st value (110 C). This suggested an important influence of T st on the cold crystallization and, consequently, on the orientation of the amorphous phase.…”

Structure evolution of PET under step-wise and continuous deformation modes: the effect of stress relaxation on the strain-induced morphology

“…The ‹cos 2 φ› could be evaluated from the full-width at half maximum (Δφ) of the Gaussian azimuthal intensity distribution by evaluating the integral for each value of Δφ from the relation [5] :…”