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Priprava industrijske vode iz reke Mure : diplomsko delo visokošolskega študija
Lidija Fras Zemljič, 1998, undergraduate thesis

Published: 26.07.2007; Views: 1765; Downloads: 0

3.
ELEMENTARNA KARAKTERIZACIJA FUNKCIONALIZIRANIH VLAKEN
Marko Munda, 2011, undergraduate thesis

Abstract: V nalogi je izvedena protimikrobna funkcionalizacija dveh vlaknotvornih polimerov (naravni polimer: celuloza, sintetični polimer: polietilentereftalat) ki se najpogosteje uporabljata v najnaprednejših panogah kot so embaliranje živilskih izdelkov, razvoj novih medicinskih in sanitetnih materialov, ter vsadkov, itd. Za funkcionalizacijo le-teh smo uporabili polisaharid hitozan in sicer absorbiran v obliki tankih površinskih slojev s katerimi vnašamo v vlakna nove funkcionalne skupine, ki so gonilna sila biološke aktivnosti. Zatorej je bistvenega pomena uporaba tehnik, ki omogočajo analizo površinske elementarne sestave funcionaliziranih materialov. Cilj diplomske naloge je tako preučevanje površin funkcionaliziranih materialov z uporabo spektroskopskih metod ATR-FTIR ter komplementarne Raman spektrofotometrije za kvalitativno analizo funkcionalnih skupin vlaken. Doslej se je obema tehnikama namenjalo premalo pozornosti in sta tako okviru diplomske naloge podrobno preučeni in optimirani za uporabo vlaknotvornih polimerov funkcionaliziranih s polisaharidi. Analize funkcionaliziranih PET folij so pokazale da se hitozan v obliki filma oprime nosilnega materiala le mehansko in/ali s fizikalno adsorpcijo, medtem ko pa na celuloznih vlaknih ni moč zaslediti hitozana.
Keywords: celulozna vlakna, polietilentereftalat, hitozan, funkcionalizacija, ATR FT-IR, Raman
Published: 12.10.2011; Views: 2029; Downloads: 248
.pdf Full text (1,69 MB)

4.
Funkcionalizacija vlaken s sinergistično formulacijo tenzid-polisaharid
Matej Bračič, 2011, master's thesis/paper

Abstract: Številni postopki funkcionalizacije medicinskih tekstilij so človeku in okolju neprijazni. Zaradi tega, vse večje zdravstvene osveščenosti ljudi in številnega porasta različnih bolezni se povečuje zanimanje za postopke, kjer se uporabljajo okolju prijazni alternativni polisaharidi. Večina alternativnih polisaharidov ima za tovrstno uporabo pomanjkljivosti, kot je omejena inhibicija patogenih bakterij. Ideja magistrske naloge je v razvoju sinergistične formulacije med polisaharidom hialuronsko kislino z vlažilnim učinkom in novo, naravno kationsko površinsko aktivno snovjo MKM s protimikrobnimi lastnostmi, za premaz na viskozni tkanini. Za karakterizacijo sinergistične formulacije med MKM in hialuronsko kislino smo uporabili nevtralizacijske potenciometrične titracije, potenciometrične titracije z uporabo ionselektivne elektrode, občutljive za površinsko aktivne snovi, ter fluorimetrične titracije na osnovi pirena. Rezultati so pokazali, da so interakcije med obema nad kritično koncentracijo asociacije močno kooperativnega značaja. Izoterme stopnje vezanja pa kažejo na vezavo površinsko aktivnega sredstva na hialuronsko kislino v presežku. Karakterizacijo viskozne tkanine, funkcionalizirane s sinergistično formulacijo, smo izvedli z uporabo nevtralizacijskih potenciometričnih titracij, meritvijo stičnega kota s tenziometrijo in protimikrobnim testiranjem. Funkcionalizirana viskozna tkanina izkazuje pozitiven naboj zaradi prisotnosti MKM, kar se neposredno odraža v njeni izredni redukciji patogenih bakterij. Funkcionalizacija viskozne tkanine s sinergistično formulacijo med MKM in hialuronsko kislino je inovativna in primerna za uporabo v medicinske namene, predvsem na področju celjenja ran.
Keywords: medicinske tekstilije, viskoza, površinsko aktivne snovi, polisaharidi, hialuronska kislina, potenciometrične titracije, fluorimetrična spektroskopija, tenziometrija, stični kot, protimikrobno testiranje
Published: 12.10.2011; Views: 2118; Downloads: 270
.pdf Full text (1,48 MB)

5.
Cellulose fibres functionalised by chitosan : characterization and application
Simona Strnad, Olivera Šauperl, Lidija Fras Zemljič, 2010, independent scientific component part or a chapter in a monograph

Keywords: cellulose fibers, medical applications, chitosan, antimicrobic properties
Published: 31.05.2012; Views: 1064; Downloads: 14
URL Link to full text

6.
Uporaba hitozana na tekstilijah za medicinske namene
Tijana Ristić, Matej Bračič, Andrej Zabret, Lidija Fras Zemljič, 2011, published scientific conference contribution

Abstract: Hitozan je kationski biopolimer, pridobljen iz polisaharida hitina. Zaradi svojih izjemnih lastnosti, kot so biorazgradljivost, netoksičnost in protimikrobna učinkovitost je hitozan našel uporabnost na različnih področjih, predvsem v farmaciji, medicini in tekstilni industriji. V zadnjem času je mogoče opaziti porast zanimanja za uporabo hitozana v medicinskih in higienskih aplikacijah, v obliki vlaken, membran, hidrogelov, ali kot premaz za doseganje protimikrobnih lastnosti tekstilij.
Keywords: hitozan, medicinske tekstilije, protimikrobni učinek
Published: 01.06.2012; Views: 1621; Downloads: 85
URL Link to full text

7.
Antimicrobial efficiency of functionalized cellulose fibres as potential medical textiles
Tijana Ristić, Lidija Fras Zemljič, Monika Novak, Marjetka Kralj Kunčič, Silva Sonjak, Nina Gunde-Cimerman, Simona Strnad, 2011, independent scientific component part or a chapter in a monograph

Abstract: This chapter presents an overview of methods for cellulose fibres functionalization in order to introduce antimicrobial activity. In view the need for ecologically friendly textiles antimicrobial finishing is introduced, together with some strategies for the functionalization of fibres using biodegradable polysaccharides such as the use of chitosan. Additionally,the methods used for the microbiological testing of these fibres are discussed and the current disadvantages of these methods indicated. Moreover, a new strategy for a reliable methodology regarding the antimicrobial testing of oriented fibre-based polymers such as cellulose is discussed, which could also be useful within several other polymer industrial fields.
Keywords: anitmicrobial agents, medical textiles, cellulose fibres, microbiological test, antimicrobial efficiency
Published: 01.06.2012; Views: 1517; Downloads: 43
URL Link to full text

8.
Analysis of the oxidation of cellulose fibres by titration and XPS
Lidija Fras Zemljič, Leena Sisko Johansson, Peer Stenius, Janne Laine, Karin Stana-Kleinschek, Volker Ribitsch, 2005, original scientific article

Abstract: The purpose of this study was to evaluate the effect of selective oxidation on the surface properties of cotton cellulose fibres. Four different methods to evaluate the accessibility, nature and content of ionisable acidic groups (charge) in the fibres were applied: potentiometric and conductometric titrations, polyelectrolyte adsorption and X-ray photoelectron spectroscopy (XPS). The results from this combination of methods show that two processes take place when the oxidation method is applied: elimination of low molecular mass non-cellulosic compounds and formation of new acidic groups in the cellulose chains. Which of these processes is predominating depends on oxidation time, but the first one is initially more important. Polyelectrolyte adsorption and XPS show that the surface concentration of acidic groups is considerably lower than the bulk concentration, i.e. during oxidation the content of carboxyl groups in the surface region decreases, while it increases in amorphous regions. The decrease is due to the dissolution of low molecular weight compounds; the increase is due to the formation of new acidic groups. The use of titration methods in combination with XPS appears to be a very useful tool for identification of the formation and distribution of ionic groups in cotton fibres and their surfaces.
Keywords: textile fibres, cotton fibres, cellulose fibres, oxidation, X-ray photoelectron spectroscopy, XPS, acid groups in fibres
Published: 01.06.2012; Views: 1418; Downloads: 73
URL Link to full text

9.
Adsorption and antibacterial activity of soluble and precipitated chitosan on cellulose viscose fibers
Lidija Fras Zemljič, Tijana Ristić, Tina Tkavc, 2012, original scientific article

Abstract: The aim and novelty of this work was to compare the adsorption of totally-soluble chitosan (acidic solution) against the adsorption of precipitated chitosan, onto cellulose fibers. The influences of both these chitosan-adsorption procedures on a final amino groupćs content in functionalized cellulose fibers were studied, using potentiometric titration and the conventional spectrophotometric C.I. Acid Orange 7 method. Surface modification and adsorption of chitosan were, in addition, monitored by determining XPS spectra. The antimicrobial activities of both chitosan- functionalised cellulose fibers were examined, in regard to pathogen bacteria and fungus.
Keywords: functionalized viscose, chitosan solution, precipitates, potentiometric titration, spectrophotometry, antimicrobial activity
Published: 01.06.2012; Views: 1444; Downloads: 253
.pdf Full text (372,02 KB)
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10.
Mild oxidation of cellulose fibers using dioxygen as ultimate oxidizing agent
Gabriela Biliuta, Lidija Fras Zemljič, Valeria Harabagiu, Sergiu Coseri, 2011, original scientific article

Abstract: Two types of regenerate cellulose fibres were oxidized under mild conditions, by using N-hydroxyphthalimide as catalyst and molecular oxygen as ultimate oxidizing agent. The amounts of negatively charged groups introduced were determined by means of potentiometric titration. The degree of polymerization and molar mass of the oxidized fibres determined viscosimetrically, has been found to be almost unaffected during oxidation.
Keywords: viscose fibers, modal fibers, oxidation, N-hydroxyphthalimide, NHPI, phthalimide-N-oxyl radical, PINO
Published: 01.06.2012; Views: 1031; Downloads: 32
URL Link to full text

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