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1.
Influence of cross-linkers on the wash resistance of chitosan-functionalized polyester fabrics
Tanja Pušić, Tea Bušac, Julija Volmajer Valh, 2024, izvirni znanstveni članek

Opis: This study investigates the wash resistance of polyester fabrics functionalized with chitosan, a biopolymer known for its biocompatibility, non-toxicity, biodegradability and environmentally friendly properties. The interaction of chitosan with synthetic polymers, such as polyester, often requires surface treatment due to the weak natural affinity between the two materials. To improve the interaction and stability of chitosan on polyester, alkaline hydrolysis of the polyester fabric was used as a surface treatment method. The effectiveness of using cross-linking agents 1,2,3,4-butane tetracarboxylic acid (BTCA) and hydroxyethyl methacrylate (HEMA) in combination with ammonium persulphate (APS) to improve the stability of chitosan on polyester during washing was investigated. The wash resistance of polyester fabrics functionalized with chitosan was tested after 1, 5 and 10 washes with a standard ECE detergent. Staining tests were carried out to evaluate the retention of chitosan on the fabric. The results showed that polyester fabrics functionalized with chitosan without cross-linkers exhibited better wash resistance than the fabrics treated with crosslinkers.
Ključne besede: polyster, functionalization, chitosan, cross-linkers, stability, washing
Objavljeno v DKUM: 10.09.2024; Ogledov: 55; Prenosov: 13
.pdf Celotno besedilo (17,25 MB)
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Influence of the temperature on the efficiency of cellulose treatment using copolymer chitosan-eugenol
Olivera Šauperl, Jasna Tompa, Julija Volmajer Valh, 2014, izvirni znanstveni članek

Opis: In order to achieve effective antimicrobial protection of textile materials against microorganisms, a natural compound called chitosan has become very interesting. In regard to the antimicrobial protection of textile materials, functionalization with chitosan does not affect some other properties, such as anti-oxidative or any other action. For this reason, it seems appropriate for chitosan to be combined with any natural antimicrobial active compound, such as eugenol, an extract of clove oil. During this research viscose as a representative of cellulose fibers was used, because it can be functionalized relatively easily. In terms of functionalization, the drying temperature of viscose, after antimicrobial compound application onto substrate, as well as the successful synthesis of copolymer chitosan/eugenol is also important. FTIR spectroscopy was used to evaluate the efficiency of synthesizing a chitosan/eugenol graft copolymer. The spectrophotometric method Acid Orange 7 was chosen as a means for determining the proportion of available antimicrobial active amino groups. In addition, microbiological testing of selected pathogenic micro-organisms was also performed. The results were compared with the results for viscose functionalized by a 1% solution of chitosan.
Ključne besede: chitosan, eugenol, functionalization, viscose, FTIR spectroscopy, Acid orange 7, antimicrobial
Objavljeno v DKUM: 02.08.2017; Ogledov: 1355; Prenosov: 495
.pdf Celotno besedilo (233,00 KB)
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4.
Chemical binding of chitosan and chitosan nanoparticles onto oxidized cellulose
Olivera Šauperl, Mirjana Kostić, Jovana Milanovic, Lidija Fras Zemljič, 2015, izvirni znanstveni članek

Opis: The aim of this study was to analyze binding of chitosan and chitosan nanoparticles onto cellulose via oxidized cellulose. The ability of chitosan and chitosan nanoparticles to be adsorbed onto surfaces was determined by the use of the XPS spectroscopy which provided information about chemical composition of the fiber surface. On the other hand, the gravimetric method was also used by which the amount of chitosan and chitosan nanoparticles bounded onto surface was calculated based on the difference in masses before and after functionalization. The most important was to study the influence of aldehyde groups on the stability of chitosan binding onto cellulose. Thus, desorption of chitosan/chitosan nanoparticles from the fiber surfaces was evaluated by the presence of total nitrogen (TN) in desorption bath as well as by polyelectrolyte titrations. Together with these two methods, desorption was evaluated also by gravimetric method, where the extent of desorption was evaluated on the basis of the differences in the masses of fibers before and after desorption. It is concluded that the chitosan and chitosan nanoparticles are more efficiently bounded onto oxidized cellulose in comparison with the non-oxidized (reference) ones. Despite the binding of the positively-charged amino groups with the negative groups of cellulose and consequently smaller amount of available/residual protonated amino groups that are responsible for bioactivity, such functionalized fibers are still specifically antimicrobial.
Ključne besede: cellulose, oxidized cellulose, oxidation, chitosan, chitosan nanoparticles, FTIR, XPS, antimicrobial functionalization
Objavljeno v DKUM: 02.08.2017; Ogledov: 1416; Prenosov: 499
.pdf Celotno besedilo (144,32 KB)
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5.
Covalent binding of heparin to functionalized PET materials for improved haemocompatibility
Metod Kolar, Miran Mozetič, Karin Stana-Kleinschek, Mirjam Fröhlich, Boris Turk, Alenka Vesel, 2015, izvirni znanstveni članek

Opis: The hemocompatibility of vascular grafts made from poly(ethylene terephthalate) (PET) is insufficient due to the rapid adhesion and activation of blood platelets that occur upon incubation with whole blood. PET polymer was treated with NHx radicals created by passing ammonia through gaseous plasma formed by a microwave discharge, which allowed for functionalization with amino groups. X-ray photoelectron spectroscopy characterization using derivatization with 4-chlorobenzaldehyde indicated that approximately 4% of the –NH2 groups were associated with the PET surface after treatment with the gaseous radicals. The functionalized polymers were coated with an ultra-thin layer of heparin and incubated with fresh blood. The free-hemoglobin technique, which is based on the haemolysis of erythrocytes, indicated improved hemocompatibility, which was confirmed by imaging the samples using confocal optical microscopy. A significant decrease in number of adhered platelets was observed on such samples. Proliferation of both human umbilical vein endothelial cells and human microvascular endothelial cells was enhanced on treated polymers, especially after a few hours of cell seeding. Thus, the technique represents a promising substitute for wet-chemical modification of PET materials prior to coating with heparin.
Ključne besede: poly(ethylene terephthalate), vascular graft, biocompatibility, heparin, plasma, functionalization, haemolysis, platelet adhesion, endothelization
Objavljeno v DKUM: 21.06.2017; Ogledov: 1344; Prenosov: 351
.pdf Celotno besedilo (1,70 MB)
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6.
Synthesis of micro-composite beads with magnetic nano-particles embedded in porous CaCO[sub]3 matrix
Alenka Vesel, Aljoša Košak, David Haložan, Kristina Eleršič, 2012, izvirni znanstveni članek

Opis: A method for synthesis of soft magnetic microbeads is presented. The microbeads are made from magnetic nanoparticles dispersed in CaCO3 (calcium carbonate) matrix. The composite beads are almost perfectly spherical with a diameter of few micrometers. The majority of the composite beads consists of a porous CaCO3 matrix. Magnetic nanoparticles with a size of about 10-15 nm are made of Fe2O3. They are captured inside the pores of CaCO3 matrix during its formation. CaCO3 matrix is formed by crystallization from saturated solution of sodium carbonate and calcium chloride. The composite beads are coated with a layer of functionalized polymer. The magnetic microbeads were characterized by SEM and XPS. Different functional groups were detected by XPS measurements including SO3–,NH3+,NH2,CO32– and OH groups. The results indicate that the iron oxide particles are absent on the surface and that the polymer coating serves as a good biocompatible film.
Ključne besede: composite, surface characterization, XPS, functionalization, Fe nanoparticles, microbeads
Objavljeno v DKUM: 23.03.2017; Ogledov: 1335; Prenosov: 116
.pdf Celotno besedilo (429,86 KB)
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7.
Synthesis comparison and characterization of chitosan-coated magnetic nanoparticles prepared with different methods
Gordana Hojnik Podrepšek, Željko Knez, Maja Leitgeb, 2014, izvirni znanstveni članek

Opis: In this study, magnetic maghemite nanoparticles were prepared with the coprecipitation method, due to its simplicity and productivity. Thereafter, chitosan-coated magnetic nanoparticles were synthesized with three different methods, the micro-emulsion process, the suspension cross-linking technique and the covalent binding. Subsequently, a comparison of the used methods was done using various analyses such as Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetry (TGA), differential scanning calorimetry (DSC), vibrating-sample magnetometry (VSM) and dynamic light scattering (DLS). The characterization results from Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA) indicated a successful binding of chitosan on the magnetic nanoparticles. SEM pictures showed that spherical structured particles with an increased particle size were obtained as the chitosan layer around the particles was increased. Considering that the magnetic-separation technique has the advantages of rapidity, high efficiency, cost-effectiveness and lack of negative effect on the biological activity, these carriers may be applied in enzyme immobilization.
Ključne besede: magnetic nanoparticles, chitosan, surface functionalization
Objavljeno v DKUM: 23.03.2017; Ogledov: 1610; Prenosov: 106
.pdf Celotno besedilo (1022,83 KB)
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8.
Functionalization of AFM tips for use in force spectroscopy between polymers and model surfaces
Tina Maver, Karin Stana-Kleinschek, Zdenka Peršin Fratnik, Uroš Maver, 2011, izvirni znanstveni članek

Opis: The following work presents the use of two different methods for the attachment of different functional groups onto the AFM tip surface. Such functionalized tips then allow for further binding of molecules with different origins and natures, thus allowing for use when measuring forces, and the extent of interactions appearing between two model surfaces and in real systems. Force spectroscopy, in combination with chemical force microscopy (CFM), as used in this study, exhibits great potential for chemical sensing in the field of polymer sciences. In modern wound treatment, it is very important to know the type and ranges of interactions between different polymer materials, which are mostly crucial components of the dressings. Precise measurement of these interactions would help to choose those materials that fit together without the use of additional chemical modifications on their surfaces. Such modifications are often the cause of unpredictable complications during the course of wound healing. This same method could also be used for interaction evaluation between chosen polymer materials with biological macromolecules, which appear within the wound during the healing process. Such in vitro testing could be of great help when optimal wound dressing materials need to be chosen in order to alleviate a patient s suffering after application. Scanning electron and atomic force microscopies were used in order to prove the effectiveness and applicability of the used functionalization procedures.
Ključne besede: atomic force microscopy, chemical force microscopy, force spectroscopy, functionalization of AFM tips
Objavljeno v DKUM: 10.07.2015; Ogledov: 1905; Prenosov: 129
.pdf Celotno besedilo (550,85 KB)
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9.
Laccase-mediated functionalization of chitosan with phenolic acids and flavonoid quercetin
Mojca Božič, Selestina Gorgieva, Janez Štrancar, Vanja Kokol, 2012, objavljeni povzetek znanstvenega prispevka na konferenci

Ključne besede: functionalization, phenolic acid, flavonoids
Objavljeno v DKUM: 10.07.2015; Ogledov: 1283; Prenosov: 35
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