University of Zagreb
Repozitorij Tekstilno-tehnološkog fakulteta Sveučilišta u ZagrebuNot a member yet
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Dizajn luminiscentnim efektima na platnu od lana i kudjelje
Get PDFRad je inspiriran umjetničkom ideologijom i načinom rada i djela umjetnika Bauhausa. Kako bi se realizirala početna ideja, idejni radovi napravljeni u tehnici kolaža poslužili su kao svojevrsna maketa za sjenilo za rasvjetno tijelo. Tehnološkim postupcima i metodama izrađeni su efekti na tekstilnom materijalu, platnu od lana i kudjelje, tkanom na starinskom tkalačkom stanu prije stotinjak godina. Budući da se platno sastoji od dva različita stabljična vlakna, njihovim bijeljenjem postižu se različite nijanse bijele, što pridonosi efektnijem izgleda tkanine. Obrađeno platno fi ksirano je na metalne nosače ormarića, te tako kao cjelina stvaraju ormarić s tekstilnim sjenilom za rasvjetno tijelo koja se može primijeniti u bilo kojem interijeru
Bio-innovation in Cotton Fabric Scouring - Acid and Neutral Pectinases
Get PDFUsing biotechnology during textile processing has been known for years due to its environmental benefits and special performance of enzymes in comparison with the conventional processing of textiles. This paper deals with the bioscouring of cotton fabric with acid and neutral pectinases in comparison with alkali scouring. Variations in technological procedures, as expressed through pad-roll and exhaustion, were also identified for the bioscouring of cotton fabrics. The varied impacts of alkali, acid, and neutral pectinases on the properties of cotton fabrics throughout the processing technology were evaluated for electrokinetic phenomena, hydrophilicity, mechanical and chemical degradation, inorganic residues, and whiteness
TENCEL with a Microbial Barrier for Medical Bras
Get PDFThe goal of the research was to determine the properties of the microbial barrier TENCELr knitted fabrics intended for medical bras. The samples were tested according to a new method developed in the earlier research by the same authors. The most resistant forms of microorganisms of a pathogenic bacterial endospore of the Bacilllus genus were used to investigate microbial barrier permeability. Based on the samples tested and their characteristics, medical bra construction was developed with the aim of reducing irritation for the body part that underwent surgery. The data on the forms and measures were obtained using a 3D body scanner
ELEKTROISPREDANI NANOVLAKNASTI MATERIJALI I FILMOVI ZA REGULACIJU TOPLINE
No full textPhase change materials (PCMs) have an important role in heat energy storage, due to their ability to absorb and release heat preferably at almost equal temperature. Encapsulation of these materials provides them to perform in their full shape. Recently electrospinning has gained attention as an effective way of producing heat storing nanofibers. This thesis considers two aspects. The first one was to encapsulate a phase change material applying ecologically and economically acceptable technique of emulsion electrospinning from a water soluble polymer, polyvinyl alcohol (PVA) and a mixture of plant oils PCM. The second aspect considers polycaprolactone (PCL) not reported yet as a phase change material in the electrospinning of these types of fibers. The PCL was encapsulated through blend elecrospinning along with polyvinylidene fluoride (PVDF) as the matrix. Although many studies reported on the form stable nanofibers when incorporating PCMs, little attention was given to the effect of high heat exposure on their structure stability and mechanical behaviour. In this thesis systematic research was carried on this issue for both material types. PVDF/PCL nanofibers materials were additionally coated by a thin layer of polypyrrole (PPy) or PPy with reduced-graphene oxide (r-GO) to further investigate materials heat storing performance, crystalline structure change, temperature weight loss, mechanical behaviour as a function of temperature and thermal conductivity. The first system showed reliability in heat storing for 100 cycles of heating and cooling, with stable physical structure and fibers morphology. After heat treatment the electrospun materials with the lowest phase change material loading performed with almost unchanged mechanical properties. The PVDF/PCL showed reliable heat storing function with encapsulation efficiency of almost 50%, for the low molecular weight PCL. The thin layer of polypyrrole on the surface of the fibers resulted in the improvement of the dynamic mechanical behaviour as a function of temperature, after materials exposure to firmly higher temperature than PCL’s melting point. The addition of the r-GO had a negligible effect on the temperature and enthalpies of melting and crystallization, while thermal conductivity increased gradually with the change of fibers surface coating during PCL solid phase. With the rapid development of electrospun nanofibrous materials towards commercialization, these types of materials can be used as thermo-regulating fabrics in protective clothing or passive heat storing devices.Materijali s promjenom stanja (eng. phase change materials - PCMs) imaju važnu ulogu kod latentne pohrane toplinske energije, obzirom na sposobnosti apsorpcije i oslobađanja topline, po mogućnosti, kod gotovo jednake temperature. Kako bi ovi materijali funkcionirali u potpunosti, poglavito u kritičnom trenutku prijelaza iz krutine u kapljevinu, moraju biti kapsulirani. Nedavno se i tehnika elektroispredanja pokazala kao učinkovit način za proizvodnju nanovlakana za pohranu topline. U ovom doktorskom radu najprije su proizvedena nanovlakna iz mješavine biljnih ulja (u nastavku označen kao PCM) i polivinil akolhola (PVA) uz ekološki prihvatljive tehnike elektroispredanja iz emulzije. Zatim su proizvedena nanovlakna iz polikaprolaktona (PCL), s manjom i većom molekulskom masom, koji do sada nije korišten kao materijal s promjenom stanja za elektroispredena vlakna. PCL je kapsuliran u polivinilidenfluoridnu (PVDF) matricu elektroispredanjem iz polimerne mješavine. Istraživanja su do sada pokazala da vlakna koja kapsuliraju materijale s promjenom stanja imaju stabilnu strukturu, međutim vrlo mala pozornost je posvećena na stabilnost strukture, te mehaničko ponašanje nakon izlaganja ovih materijala većim temperaturama, pri kojima je ovaj materijal u stanju kapljevine. Slijedom ovog razmišljanja u ovom doktorskom radu sustavno je provedeno istraživanje u vezi navedene problematike. PVDF/PCL nanovlaknasti materijali dodatno su obrađeni nanosom površinskog sloja polipirola (PPy-a), te PPy-a u kombinaciji s reduciranim grafenovim oksidom (r-GO) kako bi se ispitao njihov utjecaj na sposobnost pohrane topline, kristalnu strukturu, mehaničko ponašanje u ovisnosti o temperaturi, te na toplinsku vodljivost
Modififi ed Cotton Socks Possibility to Protect from Diabetic Foot Infection
Get PDFDiabetes has become a major public health problem and grows rapidly in the most developed countries of the world. Beside genetic and environmental factors, lifestyle habits play an important role in the development and progression of diabetes mellitus. According to the World Health Organization (WHO) about 15% of diabetic patients develop a foot ulcer in need of medical care. Infection is a serious complication and it is the major responsible cause of lower limb amputation. In this paper the possibility to protect from diabetic foot infection with modifi ed cotton socks. Therefore, the socks made of modifi ed cotton yarn by natural minerals and active carbon were investigated in vitro (fabric hand friction and adsorption) and in vivo (3 IDDM, 4NIDDM, 3 GDM to sweat and fabric hand) to accomplish highest possible level of comfort for diabetic patients. Antimicrobial protection to Gram positive, Gram negative and micro fungi was determined as well. For durability all the characteristics were investigated after 15 washing cycles
Discrepancy of Whiteness and UV Protection in Wet State
Get PDFThe incidence of skin cancer is increasing by epidemic proportions. Basal cell cancer remains the most common skin neoplasm, and simple excision is generally curative. On the other hand, aggressive local growth and metastasis are common features of malignant melanoma, which accounts for 75 percent of all deaths associated with skin cancer. In Croatia only, more than 20.000 new cases of skin cancer has been diagnosed in 2008 of which melanoma 286 new cases and 118 yearly deaths in men, and 275 new cases and 79 deaths in women population. The back sides in men and women, as well as the lower limbs in women, are the most common site for melanomas. The primary cause of skin cancer is believed to be a long exposure to solar ultraviolet (UV) radiation crossed with the amount of skin pigmentation in the population. There are indications that other parts of solar spectrum (e.g. blue light) might also have effects on skin and eyes. Most people think all clothing will protect them, but thats not the case. UV clothing can show UV protection, but in the most cases it does not provide full sun screening properties. UV protection ability highly depends on large number of factors such are type of fi ber, fabric surface and construction, type and concentration of dyestuff, fl uorescent whitening agent (FWA), UV-B protective agents, as well as nanoparticles, if applied. For that reason, jeans and tightly woven fabrics offer a very good level of protection. However, on a hot summer day, those arent the kinds of clothing people usually reach for. More often, when they are on the beach, they wear T-shirt, as well during the swimming in the sea, thinking that it will protect them. Therefore, in this paper the discrepancy of UV protection in wet state was researched. For the purpose, FWA and UV absorber were applied in wide concentration range to white cotton knit fabrics commonly used for T-shirts. Afterwards, the discrepancy in whiteness and UV protection was research in distilled water as well as Adriatic Sea water
LIGHT CONVERSION AND SCATTERING IN UV PROTECTIVE TEXTILES
Get PDFThe primary cause of skin cancer is believed to be a long exposure to solar ultraviolet radiation (UV-R) crossed with the amount of skin pigmentation in the population. It is believed that in childhood and adolescence 80% of UV-R gets absorbed, whilst in the remaining 20% gets absorbed later in the lifetime. This suggests that proper and early photoprotection may reduce the risk of subsequent occurrence of skin cancer. Textile and clothing are the most suitable interface between environment and human body. It can show UV protection, but in most cases it does not provide full sun screening properties. UV protection ability highly depends on large number of factors such as type of fibre, fabric surface and construction, type and concentration of dyestuff, fluorescent whitening agent (FWA), UV-B protective agents, as well as nanoparticles, if applied. Based on electronically excited state by energy of UV-R (usually 340370 nm), the molecules of FWAs show the phenomenon of fluorescence giving to white textiles high whiteness of outstanding brightness by reemitting the energy at the blue region (typically 420470 nm) of the spectrum. By absorbing UV-A radiation, optical brightened fabrics transform this radiation into blue fluorescence, which leads to better UV protection. Natural zeolites are rock-forming, microporous silicate minerals. Applied as nanoparticles to textile surface, it scatters the UV-R resulting in lower UV-A and UV-B transmission. If applied with other UV absorbing agents, e.g. FWAs, synergistic effect occurs. Silicones are inert, synthetic compounds with a variety of forms and uses. It provides a unique soft touch, is very resistant to washing and improves the property of fabric to protect against UV radiation. Therefore, the UV protective properties of cotton fabric achieved by light conversion and scattering was researched in this paper. For that purpose, the stilbene-derived FWAs were applied on cotton fabric in wide concentration range without/with the addition of natural zeolite or silicone polydimethylsiloxane. UV protection was determined in vitro through ultraviolet protection factor. Additionally, the influence to fabric whiteness and hand was researched
Cumulative effects of washing on properties of cotton fabrics and their blends
Get PDFApart from removing soils and preventing redeposition, chemical and mechanical activities during washing also change the structure of the textile treated. The intensity of these changes is dependent on the initial level of quality of the textiles treated, as well as upon the processing conditions (temperature, washing agent, mechanical parameters, number of washing cycles, etc). The aim of this paper was study cumulative effects of washing on properties of cotton fabrics and their blends through RAL-GZ 992 quality criteria evaluated through ash content, whiteness, tint deviation, mechanical and chemical damage. Electrokinetic potential, pilling resistance and morphology of cotton and their blends were selected as evaluation criteria for surface characterization of cotton and their blends after multiple washing cycles
An Efficient Synthesis of Pyridoxal Oxime Derivatives under Microwave Irradiation
Get PDFQuaternary salts of pyridoxal oxime have been synthesized by the quaternization of pyridoxal oxime with substituted phenacyl bromides using microwave heating. Microwave-assisted rapid synthesis was done both in solvent (acetone) and under solvent-free conditions. Good to excellent yields (58%94%) were obtained in acetone in very short reaction times (35 min) as well as in the solvent-free procedure (42%78%) in very short reaction times (710 min) too. Effective metodologies for the preparation of pyridoxal oxime quaternary salts, having the advantagies of being eco-friendly, easy to handle, and performed in shorter reactions time are presented. The structure of compound 7, in which a 4-fluorophenacyl moiety is bonded to the pyridinium ring nitrogen atom, was unequivocally confirmed by the single-crystal X-ray diffraction method
Study on the Inuence of Calendaring Process on Thermal Resistance of Polypropylene Nonwoven Fabric Structure
Get PDFThepurposeofthispaperistoinvestigatetheinuenceofcalenderingprocessonpolypropylenenonwoven structureandthermalresistance. Thestudywasfocusedontheinuenceofmassperunitarea, thickness, density, porosity, characteristic opening size and additional thermal bonding by calendering. Thermal resistance of polypropylene nonwoven fabric manufactured using the mechanical carding process and bonding using the needling process, where a part of the samples was additionally bonded by the thermal calendering process, were investigated. The nonwoven fabrics were tested for thermal resistance on the guarded hot plate. Statistical analyses were performed to examine the signicance between the observed parameters. Correlation matrix analyses were used to reveal relationship behaviour among the variables. A change in structure of the calendered samples caused a considerably lower thermal resistance i.e. better thermal conductivity. A change of the average value of thermal resistance after calendering related to non-calendered fabric mass between 150 and 500 g/m2 ranged from 53.9 to 41.0%. With increasing nonwoven fabric mass, the dierence between thermal resistances of needled and needled as well as additionally bonded by calendering the nonwoven fabric was reduced