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12. Degradation and Stabilization of Polymer MaterialsBranka Mušič, Andrijana Sever Škapin, 2023, short scientific article Keywords: polymer-based materials, nano, micro, and macro composites, effects on (micro) organisms and toxicity, impact on the ecosystem, mechanisms and products of accelerated aging and degradation, physical, chemical, mechanical, thermal, and morphological, analysis, biodegradability, sustainability, life cycle, renewable and recycled resources and the circular economy
Published in DiRROS: 21.12.2023; Views: 236; Downloads: 82
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13. Microwave irradiation of alkali - activated metakaolin slurryBarbara Horvat, Branka Mušič, Majda Pavlin, Vilma Ducman, 2023, published scientific conference contribution Abstract: The building and civil engineering industry generates more than 40% of man-caused carbon emissions, consumes a lot of energy just to produce building materials, generates a large amount of waste through construction and demolition, and consumes a large amount of natural resources. One of the possible solutions is to use alkali-activated materials, which can use waste instead of raw materials and are produced at lower temperatures, with less energy consumption and in less time than traditional building products. All of this lowers the carbon footprint, which could be further reduced by the timely-short implementation of microwave irradiation in the early stages of alkali-activation synthesis. Therefore, metakaolin activated with Na-water glass in a theoretically optimal ratio was irradiated with microwaves of 2.45 GHz at powers of 100 W and 1000 W for 1 min, and compared to non-irradiated reference cured only at room conditions. Samples prepared at higher power, i.e., 1000 W, solidified completely and foamed. TG-DTA was performed on all samples in the early stages of curing, mechanical strengths were measured on 3 and 28-day- old samples, and leaching tests on aged samples.
Keywords: metakaolin, alkali activated material, alkali activated foams, microwave irradiation
Published in DiRROS: 28.11.2023; Views: 238; Downloads: 101
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14. O akupunkturi : informacije za bolnikeIztok Potočnik, Branka Stražišar, Tanja Bohinc, Ajša Repar, Teodora Zupanc, Milena Kerin-Povšič, 2023, dictionary, encyclopaedia, lexicon, manual, atlas, map Keywords: akupunktura, medicina, kitajska medicina, bolniki
Published in DiRROS: 22.11.2023; Views: 335; Downloads: 144
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15. UV light causes structural changes in microplastics exposed in bio-solidsS. S. Alavian Petroody, Seyed Hossein Hashemi, Luka Škrlep, Branka Mušič, Cornelis A. M. van Gestel, Andrijana Sever Škapin, 2023, original scientific article Abstract: Bio-solids (biological sludge) from wastewater treatment plants are a significant source of the emission of microplastics (MPs) into the environment. Weakening the structure of MPs before they enter the environment may accelerate their degradation and reduce the environmental exposure time. Therefore, we studied the effect of UV-A and UV-C, applied at 70 °C, on three types of MPs, polypropylene (PP), polyethylene (PE), and polyethylene terephthalate (PET), that are commonly found in sewage sludge, using three shapes (fibers, lines, granules). The MPs were exposed to UV radiation in bio-solid suspensions, and to air and water as control. The structural changes in and degradation of the MPs were investigated using Attenuated Total Reflectance–Fourier Transform Infrared Spectrometry (ATR-FTIR) and surface morphology was performed with SEM analysis. UV exposure led to the emergence of carbonyl and hydroxyl groups in all of the PP samples. In PE and PET, these groups were formed only in the bio-solid suspensions. The presence of carbonyl and hydroxyl groups increased with an increasing exposure time. Overall, UV radiation had the greatest impact on the MPs in the bio-solids suspension. Due to the surface-to-volume ratio of the tested samples, which influences the degradation rate, the fibers were more degraded than the other two plastic shapes. UV-A was slightly more effective at degrading the MPs than UV-C. These findings show that ultraviolet radiation in combination with an elevated temperature affects the structure of polymers in wastewater bio-solids, which can accelerate their degradation.
Keywords: microplastics, degradation, hydroxyl, carbonyl, ultraviolet light
Published in DiRROS: 14.11.2023; Views: 298; Downloads: 154
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16. Textile industry as a major source of microplastics in the environmentBranka Mušič, 2023, review article Abstract: This review brings together data on the impact of (micro)plastics, on the environment. Critically evaluates studies on the use of various techniques for recycling textile plastic, which is a major polluter of the environment. In this review, let’s focus a bit more on industrial waste in the textile industry since it would be easiest possible to capture and recycle it again. We also discuss LCA studies, bottlenecks, and future perspectives, for a lower impact on the environment. The main challenges which make further recycling progress difficult are discussed, such as the lamination of textile fibers with metal, new textile fibers that appear as a result of rapid development, the difference in the density of textile fibers, low recycling efficiency, etc. Finally, the possible uses of more environmentally friendly polymers are shown, which can be an alternative to the current synthetic polymers. The results of the literature review showed that for the development of a sustainable textile industry, which would mitigate the impact of microplastics on the environment, from a long-term perspective, the integration of more intensive, complex decisions into the business models of manufacturing companies is necessary. The environmental consequences will be even more intense due to the massive releases of textile microfibers into the environment and excessive accumulation, therefore, in order to achieve the specific goals of sustainable development, a reduction in the production of microplastics is first required, which is only possible with a global partnership of all countries to achieve a specific goal on a global level.
Keywords: textile plastics, microplastics, environment, industrial textile waste, LCA, synthetic polymers alternative, recycling techniques
Published in DiRROS: 05.09.2023; Views: 270; Downloads: 147
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17. Posebnosti anestezije pri morbidno debelem bolniku z rakom : prikaz primeraIztok Potočnik, Tea Nizič, Branka Stražišar, 2023, review article Abstract: Debelost je kronična bolezen, za katero je značilno čezmerno kopičenje maščevja v telesu. Debeli bolniki imajo pogosto številne pridružene bolezni ter anatomske in presnovne spremembe, ki so povezane z večjim tveganjem za zaplete v perioperativnem obdobju. Debelost tako pomembno vpliva na izbiro anestezijske tehnike in zahteva multidisciplinarni pristop. V prispevku predstavljamo primer 60-letne bolnice z rakom na debelem črevesu in indeksom telesne mase (ITM) 48,1 kg/m2. Perioperativno smo jo obravnavali v skladu s protokolom za hitro okrevanje po kirurškem posegu (angl. Enhanced Recovery After Surgery, ERAS). Pred kirurškim posegom smo ocenili morebitna tveganja in jih upoštevali pri vodenju anestezije med kirurškim posegom. Po posegu smo bolnico obravnavali v enoti intenzivne terapije (EIT). V prispevku se osredotočamo na anesteziološke vidike perioperativnega vodenja. Čeprav je debelost nedvomno pomemben dejavnik tveganja kirurškega zdravljenja, pa v novejših raziskavah poročajo tudi o ugodnih vplivih debelosti z manjšo perioperativno obolevnostjo in smrtnostjo. Gre za t. i. paradoks debelosti, saj čezmerna telesna masa velja za zaščitni dejavnik, ki varuje pred zapleti kirurškega zdravljenja, kar smo potrdili tudi v našem primeru. Hkrati smo opredelili kritične točke pri anesteziji morbidno debelega bolnika in tista področja, na katerih lahko anesteziologi – ob upoštevanju protokola ERAS – pomembno prispevamo k bolnikovemu čim hitrejšemu okrevanju
Keywords: debelost, indeks telesne mase, kirurgija
Published in DiRROS: 27.07.2023; Views: 273; Downloads: 68
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18. Influence of weathering on the degradation of cellulose acetate microplastics obtained from used cigarette buttsBranka Mušič, Anita Jemec Kokalj, Andrijana Sever Škapin, 2023, original scientific article Abstract: Cellulose acetate is used in many applications, including for cigarette filters. Unfortunately, unlike cellulose, its (bio)degradability is under question, yet it often ends up uncontrolled in the natural environment. The main purpose of this study is to compare the effects of weathering on two types of cigarette filter (classic filters and newer filters that have more recently arrived on the market) following their use and disposal in nature. Microplastics were prepared from polymer parts of used (classic and heated tobacco products—HTP) cigarettes and artificially aged. TG/DTA, FTIR, and SEM analyses were performed both before and after the aging process. Newer tobacco products contain an additional film made of a poly(lactic acid) polymer which, like cellulose acetate, burdens the environment and poses a risk to the ecosystem. Numerous studies have been conducted on the disposal and recycling of cigarette butts and cigarette butt extracts, revealing alarming data that have also influenced the decisions of the EU, who addressed the disposal of tobacco products in the EU Directive (EU) 2019/904. Despite this, there is still no systematic analysis in the literature evaluating the impact of weathering (i.e., accelerated aging) on the degradation of cellulose acetate in classic cigarettes compared with that in newer tobacco products that have recently appeared on the market. This is of particular interest given that the latter have been promoted as being healthier and environmentally friendly. The results show that in cellulose acetate cigarette filters the particle size decreased after accelerated aging. Also, the thermal analysis revealed differences in the behavior of the aged samples, while the FTIR spectra showed no shifts in the position of the peaks. Organic substances break down under UV light, which can be seen by measuring the color change. The PLA film was found to be more stable than cellulose acetate under the influence of UV light.
Keywords: cellulose acetate, cigarette filters, microplastics, artificial weathering, polymer degradation
Published in DiRROS: 30.06.2023; Views: 340; Downloads: 211
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19. Flame retardant behaviour and physical-mechanical properties of polymer synergistic systems in rigid polyurethane foamsBranka Mušič, Nataša Knez, Janez Bernard, 2022, original scientific article Abstract: In the presented work, the influence of two flame retardants—ammonium polyphosphates and 2,4,6-triamino-1,3,5-triazine on the polyurethane foam (PUR) systems were studied. In this paper, these interactive properties are studied by using the thermal analytical techniques, TGA and DTA, which enable the various thermal transitions and associated volatilization to be studied and enable the connection of the results with thermal and mechanical analysis, as are thermal conductivities, compression and bending behavior, hardness, flammability, and surface morphology. In this way, a greater understanding of what the addition of fire retardants to polyurethane foams means for system flammability itself and, on the other hand, how this addition affects the mechanical properties of PUR may be investigated. It was obtained that retardants significantly increase the fire resistance of the PURs systems while they do not affect the thermal conductivity and only slightly decrease the mechanical properties of the systems. Therefore, the presented systems seem to be applicable as thermal insulation where low heat conductivity coupled with high flame resistance is required.
Keywords: flammability, polyurethane polymer, foams, thermal conductivity, mechanical properties, open access
Published in DiRROS: 08.06.2023; Views: 332; Downloads: 162
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