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  • Small angle x-ray diffraction studies of PET fibres
    Sfiligoj-Smole, Majda ; Zipper, P. ; Jeler, Slava
    The application of supercritical fluids (SCF) to the technological processes of fibre treatment is becoming increasingly important. Therefore we investigated highly oriented semicrystalline ... unmodified poly(ethylene terephalate) fibers by means of SAXS in order to study the influence of supercritical CO2 (critical data: Tc = 304.2 K, pc = 7.38 MPa) , an environment-friendly dyeing media, on the lamellar structure and on the content, size and shape of macrovoids in the fibers. Blind dyeing was performed in an autoclave after two different methods: the isothermal-isobaric method and the temperature-pressure step method. To elucidate the effects of the treatment conditions on the macrovoid system and the lamellar colloid structure, scattering curves of untreated and treated fibres were determined in equatorial and meridional directions, and small angle x-ray photographs were taken as well. Several parameters pertaining to the void system and the long period of the fibres were derived therefrom. The results suggest that the microvoid system of the fibres is more influenced by the SCF than the lamellar structure. As the treatment conditions in SCF were adapted to the dyeing conditions, they are probably too low to cause considerable changes in the two-phase fibrillar structure. Within the treatment levels used only the highest temperature changes the long period significantly, but there is no significant difference in the crystallinity according to the treatment conditions. The content of the free volume in the untreated PET fibres is very low, as expected. Due to the physical treatment at the SCF conditions, some modifications of the microvoid system were observed
    Source: Progress in colloid & polymer science. - ISSN 0340-255X (Vol. 105, 1997, str. 85-90)
    Type of material - article, component part
    Publish date - 1997
    Language - english
    COBISS.SI-ID - 3001366