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Functionalisation of oriented polymer material
Karin Stana-Kleinschek, Zdenka Peršin, 2008, professional article

Published: 31.05.2012; Views: 676; Downloads: 20
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Zoom on EPNOE activities : EPNOE road map
Karin Stana-Kleinschek, Zdenka Peršin, 2009, other component parts

Published: 31.05.2012; Views: 1046; Downloads: 15
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Use of AFM force spectroscopy for assessment of polymer response to conditions similar to the wound, during healing
Uroš Maver, Tina Maver, Andrej Žnidaršič, Zdenka Peršin, Miran Gaberšček, Karin Stana-Kleinschek, 2011, original scientific article

Abstract: Force spectroscopy is a very promising technique for the evaluation of interactions within different environments. Knowledge about them is especially important during the design and preparation of those modern wound dressings in contact with a changing wound-environment over a prolonged time. Such exposure can cause a drastic decrease in the materialćs mechanical performance, and can lead to degradation, thus lowering the success of any healing process. Our study tries to establish a model system, which would enable us to assess the applicability of the mentioned technique for the evaluation of any interaction changes between polymer molecules and a chosen surface, after exposure to different environments. Our proposed experimental setup consists of two representative polymers, a model silicon surface, and two solutions of various pHs and ionic strengths, respectively. Within the chosen range of parameters, we are confident that we can prove the usefulness of force spectroscopy for further research into polymer suitability, for the development of novel wound dressings.
Keywords: force spectroscopy, AFM, wound dressings, polymer materials, model system
Published: 01.06.2012; Views: 997; Downloads: 43
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The interaction ability of cellulosic materials as a function of fine structure and Helmholtz surface energy
Tatjana Kreže, Karin Stana-Kleinschek, Volker Ribitsch, Zdenka Peršin, Majda Sfiligoj-Smole, 2005, original scientific article

Abstract: Many chemical or physical modification processes significantly influence the accessibility of fiber forming polymers by causing structural changes. The wettability and sorption ability improvements of polymeric materials are major tasks during finishing processes. Different pre-treatment processes are used in order to improve the accessibility of dissociable groups, hydrophilicity, dyeability, and whiteness. These are usually alkaline purification, chemical bleaching and mercerization. In a previous paper we presented the data for structural characteristics (density, crystallinity index, molecular orientation, void volume, diameter and the specific inner surface of void, etc.) of untreated regenerated cellulose fibers (viscose, modal and lyocell) [41]. We now compare the influence of different pre-treatment processes on fiber structure and the accessibility of the chemical groups of these fibers. In order to improve the accessibility, two pre-treatment processes were used: chemical bleaching of fibers and tensionless alkali treatment. The influence of these pre-treatment processes on the structure parameters was evaluated using viscosity measurements (determination of polymerization degree (DIN 54 270)) and iodine sorption ability measurements according to the Schwertassek method (determination of crystallinity index) [13, 16]. The reactivity and accessibility in a polar environment was determined using tensiometry. Contact angles between the fibers and liquids of different polarities were determined using the powder contact angle method and calculated from a modified Washburn equation [26, 28]. The surface free (Helmholtz) energy of differently treated fibers was determined from the contact angle data using the Owens-Wendt-Raeble-Kaelble approximation [30, 33, 35]. The differences in the accessibility of raw and pre-treated regenerated cellulose fibers obtained using tensiometry are compared with the results of the conventional method used to determine moisture adsorption (DIN 54 351, DIN 53 802). In regard to raw fibers, viscose shows the most hydrophilic characteristic: adsorbs the highest amount of moisture, has the fastest penetration velocities (Fig. 6), the smallest contact angle, and the highest SFE (Fig. 8). Modal fibers have the largest contact angle, the lowest SFE, and they adsorb the smallest amount of water vapor. Pre-treatments increase the sorption ability and the surface free (Helmholtz) energy while they decrease the contact angle. This makes the material more accessible to water and chemicals used in the finishing processes although the crystallinity index increases. The main modification in polymer properties caused by the treatments is an increase in the fiber SFE caused by an increase of the fiber surfaces because of swelling in the alkaline medium (washing, slack-mercerization), and due to an increase of accessible OH- and COOH-groups (bleaching). This enables the formation of an increased number of hydrogen bridges between the water molecules and the OH- and COOH-groups. Our investigations confirm the results published earlier thatthe main property necessary for the proper sorption behavior of cellulose materials are the accessible, less ordered regions and not the degree of crystallinity.
Keywords: regenerated cellulose fibers, fiber pre-treatment, iodine sorption, cristallinity, tensiometry, contact angle, Helmholtz surface energy, water adsorption
Published: 01.06.2012; Views: 1557; Downloads: 19
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The plasma polymerisation process for the deposition of amino-containing film on the poly(ethylene terephthalate) dressing-layer for safe wound-healing
Zdenka Peršin, Adolf Jesih, Karin Stana-Kleinschek, 2012, original scientific article

Abstract: This article presents a new approach for preparing antimicrobial layer as a part of multi-composite dressing for safe and efficient wound - healing within a moist environment. Plasma polymerisation using a mixture of argon, ammonia, and hexane gases was used for preparing a thin polymer film on the poly(ethylene terephthalate) (PET) surface. The plasma deposition efficiency, regarding the amount of nitrogen, was evaluated by the Kjeldahl method, whilst the absorption of C.I. Acid Orange 7 dye onto accessible amino groups was monitored within the UV/VIS spectral region. The quantitative amount of charged surface groups was determined by potencometric titration. The results obtained using Kjeldahl method indicated the presence of a substantial amount of nitrogen within the deposited film. Furthermore, mono - azo acidic dye was absorbed onto the polymerised sample, pointing to the formation of an ionic bond between the sulphuric and amino groups. The plasma deposited PET samples resulted in inhibitions regarding all the pathogen microorganisms used, mostly those present in the infected wound.
Keywords: plasma polymerisation, argon, ammonia, hexane, poly(ethylene terephthalate), antimicrobial properties, wound dressing
Published: 01.06.2012; Views: 1010; Downloads: 48
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Effects of plasma treatment on water sorption in viscose fibres
Miha Devetak, Nejc Skoporc, Martin Rigler, Zdenka Peršin, Irena Drevenšek Olenik, Martin Čopič, Karin Stana-Kleinschek, 2012, original scientific article

Abstract: We investigated water sorption in viscose nonwoven fibres manufactured by Tosama d.d. with the surface density of 175 g/m2. A comparison between untreated fibres and by oxygen plasma treated fibres was made using optical polarization microscopy. Plasma treatment was done for 10 minutes at pressure of 75 Pa at current of 250 mA at the power of 500 W. Swelling was characterized by measurements of fibre diameter. Modifications of intensity of the polarized light transmitted through the fibre were measured as a function of time of exposure to water. Characteristic swelling and intensity modification times were resolved for untreated and oxygen plasma treated fibres. The swelling time of oxygen plasma in comparison to untreated plasma is reduced by the factor of 0.54 and intensity change time by the factor of 0.4. From the characteristic swelling and intensity change times it was concluded that oxygen plasma treatment of viscose increases the speed of water sorption.
Keywords: plasma treatment, viscose, optical polarization microscopy
Published: 01.06.2012; Views: 847; Downloads: 22
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Binding silver nano-particles onto viscose non-woven using different commercial sol-gel procedures
Tanja Pivec, Zdenka Peršin, Silvo Hribernik, Tina Maver, Mitja Kolar, Karin Stana-Kleinschek, 2012, original scientific article

Abstract: The paper presents possible solution of Ag binding using commercial sol-gel systems which enable its low release into a wound, providing a good antimicrobial effect on those bacterial cultures that are most likely present in the wound. The influence of different sol-gel systems on the hydrophilic properties of carrier materials and the level of released silver has been studied. The results showed that sol-gel as binding-systems could provide proper hydrophilic properties of material, whilst binding silver strongly enough providing at the same time excellent antimicrobial activity of the treated viscose meterials.
Keywords: silver nano-particles, sol-gel, viscose non-woven, silver release, hydrophilicity, antimicrobial properties
Published: 01.06.2012; Views: 1825; Downloads: 34
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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: 1117; Downloads: 23
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