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Keywords: PET vlakna, temperaturna obdelava, struktura PET vlaken, Raman spektroskopija, orientacija
Published: 26.07.2007; Views: 2040; Downloads: 0

Abstract: Two PET wool-type fibres were studied for this research, i.e. a normal wool-type and a low-pilling modification. The structural morphology and crystalline orientation of the fibres were investigated by means of wide-angle x-ray scattering (WAXS), density measurements and infrared (IR) spectroscopy. The degree of crystallinity, crystallite orientation, apparent crystallite dimensions and micro-void system were determined by x-ray scattering. Birefringence measurements were used to study the average molecular orientation and the orientation of macromolecular chain segments in the amorphous regions. In addition, PET samples were conventionally dyed and the effect of the structure on colour was followed using colorimetry. Significant differences between the two PET wool fibre types were observed; i.e. crystallinity is higher for the standard PET wool fibre type, the crystallites are slightly larger and better oriented, long periods are larger, the orientation of molecular segments in non-crystalline phase is higher, and bigger voids are formed. The observed structure gives rise to fibres higher tenacity and higher bending stiffness.
Published: 31.05.2012; Views: 1034; Downloads: 70
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Keywords: tekstilni materiali, nanotehnologija, modifikacija vlaken
Published: 15.06.2015; Views: 1175; Downloads: 48
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Abstract: Zaradi čedalje globlje ekološke ozaveščenosti in okoljevarstvenih zahtev obravnavamo v sodobnem času izdelavo, uporabo in odstranjevanje materialov veliko bolj kritično. Naravna celulozna vlakna so v tem pogledu izkazala svojo kakovost in popolnoma izpolnila vse ekološke kriterije. Naravna celulozna vlakna uporabljamo za tekstilne in tekstilnotehnične namene. To so vlakna iz ličja stebel, ki tvorijo vlaknate snopiče v notranjem ličju stebel dvokaličnic, in listna vlakna, ki tečejo po dolžini listov enokaličnic, ter semenska vlakna in vlakna iz plodov. Lan, konopljo, juto, ramijo, sisal ter kokos uporabljamo predvsem za tehnične namene. V zadnjem času pa izjemno narašča zanimanje za obnovljive surovinske vire tudi na področju vlaken. V ospredju so vlakna rastlinskega izvora. Pri iskanju novih surovinskih virov se proučujejo številne rastline, ki ne spadajo med tradicionalne vire vlaken, da bi iz njihovih stebel ali listov izolirali vlakna uporabnih lastnosti. Pri izolaciji vlaken pridobimo tehnična vlakna, kar pomeni, da so celulozna vlakna večcelične strukture, pri katerih so posamezne celice vezane v snopiče. Poleg konvencionalnih načinov izolacije vlaken se uporabljajo tudi številni sodobni postopki, kot so biotehnološki z uporabo encimov, itd. Način, kako vlakna izoliramo, vpliva na površinsko morfologijo vlaken. V prispevku so predstavljena nekatera vlakna, ki jih pridobivamo iz kmetijskih odpadkov, kot so slama žitaric, listi ananasa, sladkorni trs, hmeljeva stebla, kinoa, vlakna iz različnih trav itd.
Keywords: tekstilna vlakna, celulozna vlakna, lignocelulozna vlakna, rastlinska vlakna, naravno obnovljiva vlakna, netradicionalna vlakna
Published: 10.07.2015; Views: 1244; Downloads: 89
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Abstract: Electrospinning is a method based on the use of electrostatic forces for producing continuous fibres with the diameter from between ten nanometres to some micrometres. Such fine fibres cannot be produced with conventional methods for the production of nonwovens. The nanofibres formed with electrospinning have an exceptionally large active surface area per mass unit (fibre surface at diameter of 100 nm equals 40 $m^2$/g) and the spinning process itself enables a planned formation of the web structure (e.g. planned size of pores in the web by adjusting the nanofibre diameter and fibre thickness). Nanofibres can be electrospun from synthetic or natural polymers and their blends, from polymers with various nanoparticles (metal, ceramic etc), active substances etc. We can fabricate individual fibres, as well as webs with a random or planned fibre arrangement. Fibres with a complex structure, e.g. core shell or hollow fibres, can be produced with a special electrospinning method. Regarding the advantages demonstrated by the nanofibres fabricated with electrospinning, this procedure has become an important part of research in seve ral fields of use of technical textiles, e.g. shielding materials, air and oil filters in the car industry, agrotextiles and most of all medical textiles. The method can also be used in the production of batteries and photovoltaic cells. Apart from the apparatus designed for the research purpose in laboratories, pilot devices and the devices designed for the use in the industry can be found on the market. The paper comprises the introduction of the preparation procedure of nanofibres on an electrospinning apparatus, the morphological characteristics of fibres and the characteristics of electrospun webs in dependence of the conditions when forming fibres.
Keywords: nanotechnology, nanofibres, electrospinning, 3D-structure
Published: 10.07.2015; Views: 892; Downloads: 50
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