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1.
X-ray study of pre-treated regenerated cellulose fibres
Majda Sfiligoj-Smole, Zdenka Peršin, Tatjana Kreže, Karin Stana-Kleinschek, Volker Ribitsch, Susanne Neumayer, 2003, original scientific article

Abstract: Regenerated cellulose fibres have had an important role to play in the man-made fibre field. The very special characteristics of different types of regenerated cellulose fibres, e.g. mechanical properties, sorption characteristics, and aesthetics were conditioned by the differences in their fine structure due to fibre formation processes. Additionally, the finishing processes could influence the fibre structure. A study was done of the crystalline structures of a solvent-spun cellulose fibre type (Lenzing Lyocell), made according to the NMMO process, and two conventional cellulosic fibre types, made by the viscose process (Lenzing Viscose and Lenzing Modal). The fibres were pre-treated (bleached and slack mercerised) and structural changes were followed by wide angle and small angle x-ray scattering (WAXS and SAXS), respectively. The periodical structure, determined by long spacing, was nearly the same in all the different types of fibres. A slight increase was observed after the treatment of viscose and modal fibres, but an unpronounced fall of a long period accompanied the pre-treatment of lyocell fibres. Some changes in crystallinity and crystalline orientation occurred due to the treatment conditions. The structural changes were correlated to the iodinesorption and mechanical properties.
Keywords: regenerated cellulose fibres, fibre structure, fibre properties, x-ray analysis, WAXS, SAXS, cellulose pre-treatment
Published: 01.06.2012; Views: 1337; Downloads: 54
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2.
The influence of structural properties on the dye diffusion and dyeability of PA 6 fibres
Simona Strnad, Slava Jeler, Karin Stana-Kleinschek, Tatjana Kreže, 2003, original scientific article

Abstract: The relationships were investigated between the structural and dyeing properties of different structurally modified PA 6 fibers. PA 6 monofilament yarn samples were applied having different crystalline degrees and different content of alpha, respectively gamma crystalline modification. The diffusion coefficients of two different acid dyes were determined together with the content of dyestuff absorbed (under specific conditions) by fiber samples. In order to estimate colorimetry method from the viewpoint of polymer structural change detection, the colors of the dyed PA 6 samples were determined (L*, a*,b*, C*, h coordinates) and the color differences (L*, a*, b*, C*, H*, E*) were calculated between untreated standard and structurally modified samples. The dyeability of PA 6 fibers depended mainly on the way in which crystallinity had been achieved, i.e. on the materialćs history. Different crystalline modifications caused different sorption properties and fiber dyeability. Smaller increases (app 20%) of crystallinity degree caused a decrease in diffusion coefficients. Contrary to expectations, the significant increase of crystallinity degree (app 50%) had an influence on the increase ofdyeability, presumably owing to the formation of larger empty spaces in the structure. The results achieved by colorimetry were in good correlation with dye absorption measurements. The colorimetry of dyed fiber samples was sensitive enough to detect even small differences in the quantities of absorbed dyestuff.
Keywords: textiles, PA 6 fibres, dyeing, dyeability, fibre structure, crystallinity, chemical modification
Published: 01.06.2012; Views: 1543; Downloads: 16
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