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Highlights: [•] Three annealing mechanisms are present in poly (ethylene terephthalate). [•] Below the crystallization temperature interlamellar crystals form. [•] Annealing without melting occurs by lamellae thickening and is diffusion control. [•] Near the m.pt. annealing involves recrystallization followed by lamellae thickening. [ABSTRACT FROM AUTHOR]

Highlights: [•] Melting point increases with temperature and time due to thickening of lamellae. [•] Increase with temperature used to determine equilibrium melting point. [•] Growth is diffusion controlled depending on the square root of time. [•] Chain entanglements and impurities in the inter-lamellar regions slow to diffuse. [ABSTRACT FROM AUTHOR]

Highlights: [•] Isothermal crystallization kinetics of poly(ethylene terephthalate) measured by FTIR spectroscopy. [•] Crystallinity measured directly. [•] Primary and secondary crystallization measured with similar accuracy. [•] Primary attributed to growth of two-dimensional spherulites restricted by the thickness of the film. [•] Secondary to the growth of lamellae confined to regions between the lamellae. [ABSTRACT FROM AUTHOR]

Abstract: Thermal analysis-FTIR spectroscopy, TA-FTIR, has been used to characterize the phase transitions in thin films of poly(ethylene terephthalate) and it has been shown to have distinct advantages over other TA techniques in particular it was not so limited in sensitivity. Since the technique measured property, such as amorphous content or fractional crystallinity directly rather than the rate of change of the properties with time or temperature, it was not so restricted in the time scale over which measurements were made. It also had the advantage of measuring the change in concentration of different functional groups with temperature and determining the temperature range over which chain mobility set in and defining the type of molecular groups involved in the configurational changes. The change in absorbance and shift in peak position with temperature are discussed in terms of the separation of crystalline and amorphous bands as well as defining the cis/trans ratio as a function of temperature. Depending on the change in absorbance or peak position with temperature of the IR bands, they have been characterized as type I or type II behaviour. Measurements on both have been used to characterize the glass transition, crystallization and melting behaviour of PET. [Copyright &y& Elsevier]

Abstract: The vibrational spectrum of partially crystalline poly(ethylene terephthalate), PET, appears to be unduly complex in that the absorption bands are split into amorphous and crystalline modes and are sensitive to chain configuration and orientation. Assignment of the bands has accordingly proved to be difficult and lead to differences in interpretation. Two-dimensional infrared spectroscopy is a recent novel analytical technique in vibrational spectroscopy which can be used to interpret differences in the spectra with time or temperature accompanying changes in structure and morphology and has been used to analyze the development of crystallinity within a polymer in which amorphous regions are transformed into crystalline regions and involving changes in molecular configuration. Two-dimensional IR correlation spectroscopy has been successfully applied to these problems in the attempt to measure the fractional extent of crystallinity in PET as a function of time and crystallization temperature as well as changes to molecular configuration. [Copyright &y& Elsevier]

FePt films were prepared by magnetron sputtering deposition using Ar as the sputtering gas under different working pressures (0.3–0.7 Pa). The effect of sputtering gas pressure on the microstructure, magnetic, and magnetoresistance properties has been investigated. The results show that the crystallization of FePt films is strongly dependent on the Ar sputter pressure. With the decrease of Ar working pressures, the fct phase forms and the coercivity ( H c) of FePt films rises under the same annealing temperature. As a result, the giant magnetoresistance (GMR) increases by 20% at the room temperature. At 0.7 Pa, the anisotropy magnetoresistance (AMR) can be observed clearly at a low field. However, as the Ar pressure decreases, the increase of GMR leads to a degradation of AMR effect. We believe that the improvement of GMR effect results from the increase of magnetic anisotropy and spin polarization in the process of transformation from the soft magnetic fcc phase to the hard magnetic fct phase. [ABSTRACT FROM AUTHOR]