Tatjana Rijavec | University of Ljubljana (original) (raw)

Papers by Tatjana Rijavec

Materials

Flammability testing of undergarments is a topic that is often overlooked and rarely on the list ... more Flammability testing of undergarments is a topic that is often overlooked and rarely on the list of textiles to be tested for fire safety. However, it is particularly important for professionals exposed to fire risk to investigate the flammability of underwear as its direct contact with the skin can be critical to the extent and degree of skin burns. This research focuses on the suitability of affordable blends of 55 wt.% modacrylic, 15 wt.% polyacrylate, and 30 wt.% lyocell fibres that have the potential to be used for flame-resistant underwear. The influence of modacrylic fibre linear density (standard and microfibres), ring spinning processes (conventional, Sirospun, and compact), and knitted structure (plain, 2:1 rib, 2:1 tuck rib, single pique, and triple tuck) on their properties required for thermal comfort in high-temperature environments was investigated. Scanning electron and optical microscopy, FT-IR spectroscopy, mechanical testing, moisture regain, water sorption, wetta...

Textile Research Journal, 2015

This paper describes a lamination method of commercially produced silica aerogel composite and in... more This paper describes a lamination method of commercially produced silica aerogel composite and investigates its suitability for thermal insulation within protective footwear applications for severe cold and extreme high-altitude environments. A silica aerogel composite was used with a thickness of 2.7 mm and mass per unit area of 500 gm–2. Silica aerogel dust, which is generated during the crushing of brittle silica aerogel, was prevented from spreading into the environment by two-sided lamination of silica aerogel composite. A solid 5 µm thick membrane was used, reinforced with an abrasive resistant polyester knitted fabric. The thermal conductivity of laminated silica aerogel composite was comparable to that of the non-laminated one and amounted to 0.016 Wm–1K–1. Water vapor permeability of the laminated silica aerogel composite was 1.31 mgcm–2h–1. The silica aerogel composite was subjected to 30,000 cycles of flexing in order to study the impact of its irreversible crushed struct...

The modes of actions of diff erent surfactants during reactive wool dyeing using C.I. Reactive Re... more The modes of actions of diff erent surfactants during reactive wool dyeing using C.I. Reactive Red 120 was investigated at pH 3 and temperatures between 50 and 90°C. The studied surfactants included the following: the anionic surfactant sodium dodecylsulphate (SDS); the cationic surfactant n-dodecyltrimethylammonium bromide (DTAB); the nonionic surfactants Brij C10, Brij S10, Brij L23, Brij 58, Brij S20 and Brij S100; and the commercially available amphoteric product Albegal B. Compared with surfactant-free dyeing, SDS and Brij S100 slightly decreased the dye exhaustion after 360 minutes of dyeing, whereas the other studied surfactants signifi cantly increased the dye exhaustion. The enhanced dye uptake was attributed to the adsorptions of the surfactants to the wool fi bres, which increased the cationic characteristics and the hydrophilicity of the fi bre surface. The surfactants facilitate dye fi xation up to a dyeing temperature of 80°C and decrease it at 90°C. The surfactants increased the K/S values and changed the CIELAB values of the dyeing. Albegal B exhibited the strongest eff ect.

For investigation, technical fibres extracted from flax Linum usitatissimum L. fibre variety plan... more For investigation, technical fibres extracted from flax Linum usitatissimum L. fibre variety planted in Croatia and from Slovenian autochthonous variety from Bela Krajina were used. Flax steams of fibre variety were subjected to water retting for 72 hours, but flax steams of seed variety were dew retted for 4 weeks. Dried retted stems were passed through a mechanical process of breaking and scotching, which were followed by heckling and combing, where the fibres were separated in four length groups. Moisture regain, length, fineness and tensile properties were determined for each length group of both varieties. The properties of investigated flax varieties were different but comparable, as well as the properties of individual fibre’s length groups within the same variety. It was concluded that flax fibres from seed and fibre varieties have adequate morphological and mechanical properties for reinforcing polymer matrix composites.

TEKSTILEC, Sep 26, 2017

Zgodovinske ali historične tekstilije (tekstilije, ki jih hranijo muzeji) so ne oziraje se na sta... more Zgodovinske ali historične tekstilije (tekstilije, ki jih hranijo muzeji) so ne oziraje se na starost in umetniško vrednost zaradi redkosti neprecenljive in so pomembna kulturna dediščina človeštva oziroma vsakega naroda. Belokranjski otirači so okrašene zgodovinske tekstilije, ki so jih Belokranjci uporabljali na svatbah. Prebivalci Bele krajine so jih izdelovali iz domačega platna. Iz doma pridelanega lanenega in konopljenega prediva so izdelovali preje, od 19. stoletja naprej pa so za osnovo pri tkanju uporabljali tudi uvoženo bombažno prejo iz Šlezije, Češke in Moravske [1].

Tekstilec, 2013

Grobo volno največkrat uporabljajo kot polnilo za blazine in prešite odeje ali kot toplotno izola... more Grobo volno največkrat uporabljajo kot polnilo za blazine in prešite odeje ali kot toplotno izolacijo v gradbeništvu. Naša raziskava je bila osredinjena na uporabo domače volne za tehnične namene, kjer bi npr. lahko nadomestila poliuretanska polnila. V članku so predstavljeni izsledki raziskave lastnosti plastenih volnenih vlaknovin primerljive ploščinske mase, ki so bile utrjene z dvokomponentnimi poliestrskimi (BiCoPES) in enokomponentnimi polipropilenskimi (PP) vezivnimi vlakni. Kot temeljno vlakno je bila uporabljena groba domača volna. Vsebnost oprane volne v vlaknovinah je bila nad 85 odstotki. Vlak novina, utrjena s PP-vlakni, je bila kompaktnejša, tanjša in nižje trdnosti od vlaknovine, utrjene s poliestrskimi vlakni. Morfologija kohezivnih povezav (med sintetičnimi vlakni) in adhezivnih povezav (med sintetičnimi vlakni in volno) se je za PP vlakna razlikovala od BiCoPES vlaken. PP vlakna so se s segrevanjem mestoma popolnoma stalila, medtem ko se je BiCOPES-vlaknom stalil le plašč in so ohranila obliko vlaken ter zato prispevala k trdnosti vlaknovine. Adhezija med sintetičnimi vlakni in volno je bila slaba. Izmerjena toplotna prevodnost vlaknovin z vlakni PP in BiCoPES je bila primerljiva, prav tako je bila primerljiva maksimalna tlačna napetost pri maksimalni tlačni sili. Ključne besede: groba domača volna, plastene vlaknovine, vezivna vlakna, adhezija

Textile Research Journal, 2014

The influence of wet cleaning, as a promising process compared to washing, on the physical and ch... more The influence of wet cleaning, as a promising process compared to washing, on the physical and chemical properties of functional cotton fabrics with high added value is presented. Fabric characterization before and after durable press finishing and after 10 cycles of washing and wet cleaning is made using standard methods – measuring dimensional stability, construction characteristics, crease resistance, tensile properties, swelling properties, appearance with coefficient of friction and geometrical roughness, surface characterization by scanning electron microscopy and electrokinetic potential. It can be seen that wet cleaning, which has been used in practice, together with adequate pretreatment, as a substitute for dry cleaning, can also be successfully implemented as a process to substitute washing, particularly when high-value-added articles are concerned.

GLASNIK HEMIČARA, TEHNOLOGA I EKOLOGA REPUBLIKE SRPSKE, 2012

Kvalitet sportske odjeće se ocjenjuje preko njene toplotno fiziološke i ergonomske udobnosti. U ... more Kvalitet sportske odjeće se ocjenjuje preko njene toplotno fiziološke i ergonomske udobnosti. U ovom radu je ispitivana povezanost mehaničkih svojstava pletenina i ergonomske udobnosti odjeće. Sportska odjeća se izrađuje od različitih vrsta materijala koji vizuelno mogu izgledati isto, ali kada su u pitanju mehanička svojstva koja su uveliko povezana sa prilijeganjem i deformacijom odjeće u toku upotrebe, između njih može postojati značajna razlika.Za izradu ženskih biciklističkih hlača korištene su dvije vrste pletenina istih konstrukcijskih karaktristika ali različitih sirovinskih sastava. Od navedenih pletenina izrađena su dva modela ženskih biciklističkih hlača. Za izradu oba modela hlača korišteni su krojni dijelovi iste konstrukcije ali sa kombinacijama pletenina različite rastegljivosti za pojedine krojne dijelove radi postizanja bolje ergonomske udobnosti. Povezanost mehaničkih svojstava pletenina i ergonomske udobnosti modela ženskih biciklističkih hlača utvrđivana je kroz...

Smart Materials and Structures

A prototype of a new shape-memory nitinol knitted fabric intended for use as an active thermal in... more A prototype of a new shape-memory nitinol knitted fabric intended for use as an active thermal insulating interlining in firefighting protective clothing was developed in the study presented in this paper. Weft knitted fabrics were made from commercially available cold-worked nickel titanium alloy monofils. Knits were made on a manual knitting machine from a monofil measuring 0.1 mm in diameter, while a hand-made knit was prepared from a monofil measuring 0.2 mm in diameter. Nitinol fabrics were annealed at 500 °C to achieve an austenite transition temperature of 75 °C. A special constructed mould made of a steel frame and aluminium domes measuring 30 and 20 mm in height was used to give the nitinol fabrics a new temporary shape. A two-way, shape-memory effect of the nitinol fabrics was achieved using a 15-cycle training process. The achieved shape-memory effect was tested in a heated chamber at 100 °C, where bulges measuring 12–25 mm in height occurred. NiTi knits made from finer m...

Textile Research Journal

The choice of a comfortable pillow is essential for good sleep. The filling material for pillows ... more The choice of a comfortable pillow is essential for good sleep. The filling material for pillows should be bulky, resilient and comfortable. For reasons of price, availability and resilience, polyester is the most commonly used filling material. Its drawbacks, however, lie in poor moisture management and a lack of biodegradability. This is the first study of the physical and microclimate properties of pillows with carded filling containing lyocell fiber. Pillow samples were manufactured on an industrial production line. Their carded fillings were rolled and comprised either 30% or 50% lyocell, blended with polyester (virgin and recycled), high elastic triexta and biodegradable polylactide fibers. In simulated sleeping conditions, using a thermal sweating manikin, it was proven that pillows with fillings made of 50% lyocell blended with polyester demonstrated an enhanced microclimate through much better moisture management than pillows with fillings made from pure polyester. It was a...

TEKSTILEC

The importance of industrial hemp as a source of highly valuable textile fi bres is briefl y pres... more The importance of industrial hemp as a source of highly valuable textile fi bres is briefl y presented through its use for textiles and composites and its increasing cultivated areas in the 21 st century. On the territory of present Slovenia, about 160 ha of agricultural area was cultivated with hemp before WWII, then it quickly began to decline and at the end of the 1970s, it was no longer cultivated. Revitalization of industrial hemp in Slovenia with fi eld experiments started already in the years 2000/2001 for producing seeds, whereas hemp fi bres were used only as an insulation for buildings. The textile technological properties of hemp fi bres from diff erent varieties grown in Slovenia have not been examined till now. They are important for using hemp fi bres in highly valuable textile products. The properties of green hemp fi bres extracted mechanically from non-retted hemp stems of Cannabis sativa L. var. sativa (varieties: Novosadska, Juso-11, Bialobrzeskie, Unico-B and Beniko) were determined. All the analysed varieties except Beniko had stem height over 200 cm. The highest yield of green fi bres was 33.1% (Novosadska). The analysed green fi bres' content was 1.24-3.26% of ash, 7.77-8.50% of moisture regain, 10.69-13.92% of water-soluble substances and 8.45-10.83% of pectin. Through a biodegradation process of retting green hemp fi bres in tap water at temperature 35°C, 9.01-18.89% of dry mass was removed after ten days. Average linear density of green hemp fi bres was very high, around 200 tex. Tenacity of fi bres' bundles was in the range of 167-272 MPa, but tenacity of elementary fibres was 548-672 MPa. From the curves of specifi c stress-strain, it is seen that green hemp fi bres from all fi ve varieties had similar superstructure. All analysed green hemp fi bres had high linear density and low mechanical properties. For textile application, they should be further processed into fi ner fi bres in order to increase their tensile stress and become also more fl exible and soft. Keywords: Cannabis sativa, non-retted hemp fi bres, green hemp fi bres, hemp in Slovenia, revitalization of industrial hemp

Journal of the Serbian Chemical Society, 2016

Flax fibers were modified with NaOH and NaClO2 under different conditions in order to clarify eff... more Flax fibers were modified with NaOH and NaClO2 under different conditions in order to clarify effects of hemicelluloses and lignin removal on the morphology and properties of flax fibers, but also to improve fiber quality. The quality of flax fibers was characterized in terms of chemical composition, fineness, whiteness, mechanical and sorption properties. Both treatments, alkali treatment leading to hemicelluloses removal (up to 72 % of hemicelluloses removed) and chlorite treatment leading to lignin removal (up to 96 % of lignin removed), induce a modification of morphology and properties of flax fibers. For 5 % NaOH treatments, as well as all NaClO2 treatments, increase in the crystallinity was observed, while for higher NaOH concentrations, the mercerization phenomenon induces a slight decrease of the crystallinity. Modification with NaClO2 results in fiber fibrillation while modification with NaOH at boiling temperature results in smoother fiber surfaces. Both treatments cause ...