The effect of physical aging on the rates of cold crystallization of poly(ethylene terephthalate)

Crystallization of sucrose glass under ambient conditions: Evaluation of crystallization rate and unusual melting behavior of resultant crystals

“…The materials compressed using greater forces crystallized faster, perhaps due to the closeness of the neighboring molecules. This observation may be equivalent to the acceleration of the crystallization by aging,17 because it also makes the amorphous structure dense. The detailed mechanism of the bulk density effect on the crystallization is out of scope of this study, however, the sucrose glass for the following crystallization studies was fixed at 5 kgf.…”

Effect of thermal and hygrothermal aging on the plane stress fracture toughness of poly(ethylene terephthalate) sheets

“…The embrittlement induced by physical aging can be assessed by determining of the change in the yield stress (σ y -tensile tests) [2][3][4]. Furthermore it can be characterized by measuring the enthalpy relaxation (ΔH -differential scanning calorimetry, DSC) [2,[5][6][7]. Physical aging also influences the fracture mechanical properties of the polymer but only relatively few studies have been published so far.…”

Fast Scanning Calorimetry

“…Tammann's nuclei development method utilizes the often found distinct differences in the temperatures of maximum rate of crystal nucleation and crystal growth, ultimately permitting to gain quantitative information about the nucleation kinetics at low temperature. The evolution of homogeneous crystal nuclei, formed as a result of a specific thermal treatment of a sample, to crystals by heating to elevated temperature has been described for several polymers including PLLA [44][45][46][47]191] and PET [43,[192][193][194]. In particular, it has been shown that cold-crystallization is faster than melt-crystallization at identical temperature, with the observed results being explained by formation of additional crystal nuclei on the thermal pathway to the crystallization temperature.…”