| | SLO | ENG | Cookies and privacy

Bigger font | Smaller font

Search the digital library catalog Help

Query: search in
search in
search in
search in
* old and bologna study programme

Options:
  Reset


1 - 10 / 16
First pagePrevious page12Next pageLast page
1.
Functionalization of surgical mask polypropylene layers with application of natural substances
Marjana Simonič, Olivija Plohl, Maša Vračevič, Lidija Fras Zemljič, 2025, original scientific article

Abstract: The anti-viral efficacy of face mask was enhanced by applying the protein lactoferrin, the polyphenol catechin individually, and in combination. Individual solutions of protein and polyphenol were meticulously prepared and subsequently sprayed onto the inner surface of face mask layers composed of polypropylene. The functionalized mask layers were subjected to comprehensive characterization through Fourier transform infrared spectroscopy, zeta-potential measurements, and X-ray photoelectron spectroscopy. Goniometry was employed to assess the wettability of the modified surface layer, and air permeability was quantified both before and after the application of potential anti-viral agents. Bioactivity, such as anti-oxidant activity using ABTS assay and anti-viral efficiency against the model virus phi6, was followed as well. Our findings indicate the successful modification of mask with lactoferrin, while functionalization by catechin proved to be unsuccessful. The measured contact angles underscored the hydrophobic nature of the functionalized samples, ensuring reduced wettability in the presence of saliva droplets. Notably, the individual coating layers exhibited enhanced anti-oxidant activity and demonstrated anti-viral properties against the model virus phi6, when the outer layer of the mask was spray-coated. These results suggest promising technology to integrating these functionalized layers into masks for enhanced safety performance.
Keywords: catechin, lactoferrin, PP mask, spray-coating, anti-viral properties
Published in DKUM: 07.02.2025; Views: 0; Downloads: 0
.pdf Full text (1,36 MB)

2.
3.
Slot‑die coating of cellulose nanocrystals and chitosan for improved barrier properties of paper
Ylenia Ruberto, Vera Vivod, Janja Juhant Grkman, Gregor Lavrič, Claudia Graiff, Vanja Kokol, 2024, original scientific article

Abstract: Cellulose nanocrystals (CNCs) and chitosan (Cht) have been studied extensively for oxygen and water vapour barrier coatings in biodegradable, compostable or recyclable paper packaging. However, rare studies have been performed by using scalable, inexpensive, and fast continuous slot-die coating processes, and none yet in combination with fast' and high-throughput near-infrared (NIR) light energy drying. In this frame, we studied the feasibility of a moderately concentrated (11 wt%) anionic CNC and (2 wt%) cationic Cht coating (both containing 20 wt% sorbitol related to the weight of CNC/Cht), by using plain and pigment pre-treated papers. The effect of coating parameters (injection speed, dry thickness settings) were investigated on coating quantity (dry weight, thickness) and homogeneity (coverage), papers' structure (thickness, grammage, density), whiteness, surface wettability, barrier (air, oxygen and water vapour) properties and adhesion (surface strength). The coating homogeneity was dependent primarily on the suspensions' viscosity, and secondarily on the applied coating parameters, whereby CNCs could be applied at 1–2 times higher injection speeds (up to 80 mL/min) and versatile coating weights, but required a relatively longer time to dry. The CNCs thus exhibited outstanding air (4.2–1.5 nm/Pa s) and oxygen (2.7–1.1 cm3 mm/m2 d kPa) barrier performance at 50% RH and 22–33 g/m2 deposition, whereas on top deposited Cht (3–4 g/m2) reduced its wetting time and improved the water vapour barrier (0.23–0.28 g mm/m2 d Pa). The balanced barrier properties were achieved due to the polar characteristic of CNCs, the hydrophobic nature of Cht and the quantity of the applied bilayer coating that can provide sustainable paper-based packaging.
Keywords: paper, nanocellulose, chitosan, slot‑die coating, near-infrared (NIR) drying, barrier properties
Published in DKUM: 06.05.2024; Views: 227; Downloads: 12
.pdf Full text (1,59 MB)
This document has many files! More...

4.
5.
Comprehensive analysis of different coating materials on the POM substrate
Tonica Bončina, Srečko Glodež, Brigita Polanec, Lara Hočuršćak, Franc Zupanič, 2023, original scientific article

Abstract: This study presents a comprehensive analysis of different coating materials on the POM substrate. Specifically, it investigated physical vapour deposition (PVD) coatings of aluminium (Al), chromium (Cr), and chromium nitride (CrN) of three various thicknesses. The deposition of Al was accomplished through a three-step process, particularly plasma activation, metallisation of Al by magnetron sputtering, and plasma polymerisation. The deposition of Cr was attained using the magnetron sputtering technique in a single step. For the deposition of CrN, a two-step process was employed. The first step involved the metallisation of Cr using magnetron sputtering, while the second step involved the vapour deposition of CrN, obtained through the reactive metallisation of Cr and nitrogen using magnetron sputtering. The focus of the research was to conduct comprehensive indentation tests to obtain the surface hardness of the analysed multilayer coatings, SEM analyses to examine surface morphology, and thorough adhesion analyses between the POM substrate and the appropriate PVD coating.
Keywords: POM, PVD coating, metal coating, adhesion analyses, indentation tests
Published in DKUM: 15.02.2024; Views: 304; Downloads: 37
.pdf Full text (3,25 MB)
This document has many files! More...

6.
Amoxicillin doped hyaluronic acid/fucoidan multifunctional coatings for medical grade stainless steel orthopedic implants
Matej Bračič, Sanja Potrč, Matjaž Finšgar, Lidija Gradišnik, Uroš Maver, Hanna Budasheva, Dorota Korte, Mladen Franko, Lidija Fras Zemljič, 2023, original scientific article

Abstract: This work investigated the potential of amoxicillin-doped hyaluronic acid/fucoidan multifunctional coatings on medical grade stainless steel as biocompatible, osteointegration enhancing, antimicrobial, and bacterial biofilm inhibiting coatings for orthopedic implants. The coatings were prepared by layer-by-layer spin coating and confirmed by optical contact angle goniometry and infrared spectroscopy. Time-of-flight secondary ion mass spectrometry showed a homogeneous distribution of the individual layers. In contrast, thermal diffusivity, and thermal conductivity measurements by photothermal beam deflection spectrometry showed diffusion of the amoxicillin into the hyaluronic acid and fucoidan layers. In vitro release of amoxicillin showed complete release within one hour, as reflected by the formation of inhibition zones against Staphylococcus aureus and Escherichia coli. Synergistic effects were observed between the hyaluronic acid and amoxicillin in inhibiting S.Aureus biofilm, and between the fucoidan and amoxicillin in improving the antioxidant properties by an ABTS radical scavenging assay. Biocompatibility was determined with human osteoblasts, confirming the potential of such multifunc- tional coatings to enhance the bioactivity of steel-based orthop edic implants.
Keywords: orthopedic implant, medical grade stainless steel, amoxicillin, hyaluronic acid, fucoidan, multifunctional coating
Published in DKUM: 18.08.2023; Views: 588; Downloads: 108
.pdf Full text (10,18 MB)
This document has many files! More...

7.
Two-layer functional coatings of chitosan particles with embedded catechin and pomegranate extracts for potential active packaging
Sanja Potrč, Tjaša Kraševac Glaser, Alenka Vesel, Nataša Poklar Ulrih, Lidija Fras Zemljič, 2020, original scientific article

Abstract: Two-layer functional coatings for polyethylene (PE) and polypropylene (PP) films were developed for the active packaging concept. Prior to coating, the polymer films were activated by O$_2$ and NH$_3$ plasma to increase their surface free energy and to improve the binding capacity and stability of the coatings. The first layer was prepared from a macromolecular chitosan solution, while the second (upper) layer contained chitosan particles with embedded catechin or pomegranate extract. Functionalized films were analyzed physico-chemically to elemental composition using ATR-FTIR spectroscopy and XPS. Further, oxygen permeability and wettability (Contact Angle) were examined. The antimicrobial properties were analyzed by the standard ISO 22196 method, while the antioxidative properties were determined with an ABTS assay. Functionalized films show excellent antioxidative and antimicrobial efficacy. A huge decrease in oxygen permeability was achieved in addition. Moreover, a desorption experiment was also performed, confirming that the migration profile of a compound from the surfaces was in accordance with the required overall migration limit. All these properties indicate the great potential of the developed active films/foils for end-uses in food packaging.
Keywords: plasma, chitosan, polyphenols, coating, active package
Published in DKUM: 12.07.2023; Views: 618; Downloads: 55
.pdf Full text (2,70 MB)
This document has many files! More...

8.
Wear Behaviour of Multilayer Al-PVD-Coated Polymer Gears
Tonica Bončina, Brigita Polanec, Franc Zupanič, Srečko Glodež, 2022, original scientific article

Abstract: A comprehensive experimental investigation of the wear behaviour of coated spur polymer gears made of POM is performed in this study. Three different thicknesses of aluminium (Al) coatings were investigated and deposited by the Physical Vapour Deposition (PVD) process. The Al coating was deposited in three steps: By plasma activation, metallisation of the aluminium by the magnetron sputtering process, and plasma polymerisation. The wear of the gears was tested on an in-house developed testing rig for different torques (16, 20, and 24 Nm) and a rotational speed of 1000 rpm. The duration of the experiments was set to 13 h, when the tooth thickness and, consequently, the wear of the tooth flank were recorded. The experimental results showed that the influence of metallisation with aluminium surface coatings on the wear behaviour of the analysed polymer gear is not significantly important. The results also showed that the gears with a thicker aluminium coating showed greater wear than gears with a thinner coating or even without a coating. This is probably due to the fact that the aluminium particles that started to deviate during gear operation represented the abrasive material, which led to the faster wear of the contacting surfaces of the meshing gear flanks.
Keywords: polymer gears, aluminium PVD coating, Physical Vapour Deposition process, multilayer coating, wear
Published in DKUM: 15.11.2022; Views: 580; Downloads: 80
.pdf Full text (13,01 MB)
This document has many files! More...

9.
Complementary assessment of commercial photoluminescent pigments printed on cotton fabric
Selestina Gorgieva, Natalija Virant, Alenka Ojstršek, original scientific article

Abstract: The presented study focuses on photoluminescent pigments applied on cotton fabric by a screen-printed procedure using polydimethylsiloxane (PDMS) as a binder. Microscopic data depicts irregular shapes and relatively wide size distribution (3–80 µm) of pigments. Regarding composition,the Energy-Dispersive X-ray (EDX) and Fourier Transform Infrared (FTIR) spectroscopy data complement findings suggesting the presence of Eu-doped strontium aluminate in the yellow-green,calcium aluminate in the violet pigment, and metal oxides in the blue pigment.
Keywords: photoluminescent pigments, cotton fabric, screen-printing, photoluminescent PDMS coating, confocal microscopy, spectroscopy, printed cotton fabrics, pigments
Published in DKUM: 08.04.2021; Views: 982; Downloads: 89
.pdf File (10,19 MB)

10.
Design, Characterisation and Applications of Cellulose-Based Thin Films, Nanofibers and 3D Printed Structures : A Laboratory Manual
Tanja Pivec, Tamilselvan Mohan, Rupert Kargl, Manja Kurečič, Karin Stana-Kleinschek, 2021, other educational material

Abstract: The introduction of the Laboratory Manual gives the theoretical bases on cellulose and its derivatives, which are used as starting polymers for the preparation of multifunctional polymers with three different advanced techniques - spin coating, electrospinning and 3D printing. In the following, each technique is presented in a separate Lab Exercise. Each exercise covers the theoretical basics on techniques for polymer processing and methods for their characterisation, with an emphasis on the application of prepared materials. The experimental sections contain all the necessary information needed to implement the exercises, while the added results provide students with the help to implement correct and successful exercises and interpret the results.
Keywords: multifunctional polymers, polysaccharides, cellulose, electrospun, spin coating, 3D printing, nanofibers, thin films, multifunctional materials, laboratory manuals
Published in DKUM: 09.03.2021; Views: 965; Downloads: 25
URL Link to file

Search done in 0.31 sec.
Back to top
Logos of partners University of Maribor University of Ljubljana University of Primorska University of Nova Gorica