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1.
Advance analysis of the obtained recycled materials from used disposable surgical masks
Alen Erjavec, Julija Volmajer Valh, Silvo Hribernik, Tjaša Kraševac Glaser, Lidija Fras Zemljič, Tomaž Vuherer, Branko Neral, Mihael Brunčko, 2024, izvirni znanstveni članek

Opis: The production of personal protective equipment (PPE) has increased dramatically in recent years, not only because of the pandemic, but also because of stricter legislation in the field of Employee Protection. The increasing use of PPE, including disposable surgical masks (DSMs), is putting additional pressure on waste collectors. For this reason, it is necessary to find high-quality solutions for this type of waste. Mechanical recycling is still the most common type of recycling, but the recyclates are often classified as low-grade materials. For this reason, a detailed analysis of the recyclates is necessary. These data will help us to improve the properties and find the right end application that will increase the value of the materials. This work represents an extended analysis of the recyclates obtained from DSMs, manufactured from different polymers. Using surface and morphology tests, we have gained insights into the distribution of different polymers in polymer blends and their effects on mechanical and surface properties. It was found that the addition of ear loop material to the PP melt makes the material tougher. In the polymer blends obtained, PP and PA 6 form the surface (affects surface properties), while PU and PET are distributed mainly inside the injection-molded samples.
Ključne besede: mechanical recycling, disposable surgical mask, morphology, surface properties, mechanical properties, nonwoven materials, PPE
Objavljeno v DKUM: 09.04.2024; Ogledov: 62; Prenosov: 2
.pdf Celotno besedilo (8,08 MB)
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2.
Seasonal changes in chemical profile and antioxidant activity of Padina pavonica extracts and their application in the development of bioactive chitosan/PLA bilayer film
Martina Čagalj, Lidija Fras Zemljič, Tjaša Kraševac Glaser, Eva Mežnar, Meta Sterniša, Sonja Smole Možina, María del Carmen Razola-Díaz, Vida Šimat, 2022, izvirni znanstveni članek

Opis: Seaweeds are a potentially sustainable source of natural antioxidants that can be used in the food industry and possibly for the development of new sustainable packaging materials with the ability to extend the shelf-life of foods and reduce oxidation. With this in mind, the seasonal variations in the chemical composition and antioxidant activity of brown seaweed (Padina pavonica) extracts were investigated. The highest total phenolic content (TPC) and antioxidant activity (measured by ferric reducing/antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, and oxygen radical absorbance capacity (ORAC)) were found for P. pavonica June extract. The TPC of 26.69 ± 1.86 mg gallic acid equivalent/g, FRAP of 352.82 ± 15.41 µmole Trolox equivalent (TE)/L, DPPH of 52.51 ± 2.81% inhibition, and ORAC of 76.45 ± 1.47 µmole TE/L were detected. Therefore, this extract was chosen for the development of bioactive PLA bilayer film, along with chitosan. Primary or quaternary chitosan was used as the first layer on polylactic acid (PLA) films. A suspension of chitosan particles with entrapped P. pavonica extract was used as the second layer. X-ray photoelectron spectroscopy confirmed the presence of layers on the material surface. The highest recorded antioxidant activity of the newly developed films was 63.82% inhibition. The developed functional films exhibited antifogging and antioxidant properties, showing the potential for application in the food industry.
Ključne besede: functional PLA films, seaweed and chitosan bilayer, sustainable natural antioxidants, microwave-assisted extraction
Objavljeno v DKUM: 23.08.2023; Ogledov: 267; Prenosov: 17
.pdf Celotno besedilo (3,28 MB)
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3.
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, izvirni znanstveni članek

Opis: 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.
Ključne besede: plazma, citozan, polifenoli, aktivno pakiranje, plasma, chitosan, polyphenols, coating, active package
Objavljeno v DKUM: 12.07.2023; Ogledov: 414; Prenosov: 24
.pdf Celotno besedilo (2,70 MB)
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