1. Thermal, molecular dynamics, and mechanical properties of poly(ethylene furanoate)/poly(ε-caprolactone) block copolymersJohan Stanley, Panagiotis A. Klonos, Aikaterini Teknetzi, Nikolaos Rekounas, Apostolos Kyritsis, Lidija Fras Zemljič, Dimitra A. Lambropoulou, Dimitrios Bikiaris, 2024, izvirni znanstveni članek Opis: This study presents the synthesis and characterization of a series of multiblock copolymers, poly(ethylene 2,5-furandicarboxylate)-poly(ε-caprolactone) (PEF-PCL), created through a combination of the two-step melt polycondensation method and ring opening polymerization, as sustainable alternatives to fossil-based plastics. The structural confirmation of these block copolymers was achieved through Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), ensuring the successful integration of PEF and PCL segments. X-ray Photoelectron Spectroscopy (XPS) was employed for chemical bonding and quantitative analysis, providing insights into the distribution and compatibility of the copolymer components. Differential Scanning Calorimetry (DSC) analysis revealed a single glass transition temperature (Tg), indicating the effective plasticizing effect of PCL on PEF, which enhances the flexibility of the copolymers. X-ray Diffraction (XRD) studies highlight the complex relationship between PCL content and crystallization in PEF-PCL block copolymers, emphasizing the need to balance crystallinity and mechanical properties for optimal material performance. Broadband Dielectric Spectroscopy (BDS) confirmed excellent distribution of PEF-PCL without phase separation, which is vital for maintaining consistent material properties. Mechanical properties were evaluated using Nanoindentation testing, demonstrating the potential of these copolymers as flexible packaging materials due to their enhanced mechanical strength and flexibility. The study concludes that PEF-PCL block copolymers are promising candidates for sustainable packaging solutions, combining environmental benefits with desirable material properties. Ključne besede: poly(ethylene furanoate), poly(ε-caprolactone), block copolymers, thermal properties, molecular dynamics, crystallinity, mechanical properties, flexible packaging Objavljeno v DKUM: 13.03.2025; Ogledov: 0; Prenosov: 6
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2. Thermal decomposition kinetics and mechanism of poly(ethylene 2,5-furan dicarboxylate) Nanocomposites for food packaging applicationsJohan Stanley, Evangelia Tarani, Nina Maria Ainali, Tjaša Kraševac Glaser, Lidija Fras Zemljič, Konstantinos Chrissafis, Dimitra A. Lambropoulou, Dimitrios Bikiaris, 2024, izvirni znanstveni članek Opis: Poly(ethylene 2,5-furan dicarboxylate) (PEF) based nanocomposites containing different nanoparticles like Ag, TiO2, ZnO, ZrO2 Ce-Bioglass, have been synthesized via in-situ polymerization techniques targeting food pack aging applications. Zeta potential measurements showed an increase in the negative zeta potential value due to an increase in the surface charge density of the nanocomposites. Thermogravimetric analysis results proved that, except PEF-ZnO nanocomposite, all the other nanocomposites exhibited good resistance to thermal degradation without serious mass loss until 330 ◦C. Thermal decomposition kinetic analysis and the dependence of activation energy on the degree of conversion (α), indicated that the presence of ZnO nanoparticles influences, the degradation mechanism of PEF. In contrast, the presence of Ce-Bioglass nanoparticles leads to a slower degra dation process, contributing to the enhanced resistance to thermal degradation of the PEF-Bioglass nano composite. The thermal degradation mechanism of PEF nanocomposites analyzed by pyrolysis‒gas chromatography/mass spectrometry (Py-GC/MS) indicated that the primary thermal degradation mechanism for the studied nanocomposites was β-hydrogen bond scission, while to a lesser extent, α-hydrogen bond scission products were noted in PEF-TiO2 and PEF-ZrO2 nanocomposites. Ključne besede: bio based polymers, Poly(ethylene 2, 5-furan dicarboxylate), nanoparticles, thermal properties, nanocomposites, decomposition mechanism Objavljeno v DKUM: 13.03.2025; Ogledov: 0; Prenosov: 5
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3. Study on impact of monomers towards high molecular weight bio-based poly(ethylene furanoate) via solid state polymerization techniqueJohan Stanley, Eleftheria Xanthopoulou, Margaritis Kostoglou, Lidija Fras Zemljič, Dimitra A. Lambropoulou, Dimitrios Bikiaris, 2024, izvirni znanstveni članek Opis: In recent years, bio-based poly(ethylene furanoate) has gained the attention of packaging industries owing to its remarkable properties as a promising alternative to fossil-based polymers. It is necessary to synthesize high-molecular-weight polymers using effective and straightforward techniques for their commercialization. In this present work, poly(ethylene 2,5-furan dicarboxylate) (PEF) was produced with a high molecular weight of 0.43 dL/g using 2,5-furan dicarboxylic acid (FDCA) or its derivative Dimethyl-2,5-Furan dicarboxylate (DMFD), followed by solid-state polymerization (SSP) conducted at different temperatures and reaction times. The intrinsic viscosity ([η]), carboxyl end-group concentration (–COOH), and thermal properties of the produced polyesters were evaluated using differential scanning calorimetry (DSC). The results indicated that the SSP process improved the melting temperature and crystallinity of both the PEF samples as the reaction times and temperatures increased, as corroborated by DSC and X-ray diffraction (XRD) analyses. Additionally, both intrinsic viscosity and number-average molecular weight saw an increase with longer SSP durations and higher temperatures, while the concentration of carboxyl end groups decreased, aligning with expectations. The overall results indicate that PEF (DMFD) samples exhibited a significant increase in crystallization and molecular weight, attributed to their lower degree of crystallinity and their monomer’s high purity. Ključne besede: bio-based polymers, 2, 5-furan dicarboxylic acid, dimethyl 2, 5-furan dicarboxylate, poly(ethylene 2, 5-furan dicarboxylate), poly(ethylene furanoate), solid state polymerization, thermal properties Objavljeno v DKUM: 10.03.2025; Ogledov: 0; Prenosov: 7
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4. Recent trends in the synthesis of monomers for furanoate polyesters and their nanocomposites’ fabrication as a sustainable packaging materialJohan Stanley, Lidija Fras Zemljič, Dimitra A. Lambropoulou, Dimitrios Bikiaris, 2024, izvirni znanstveni članek Opis: Furanoate polyesters are an extremely promising new class of materials for packaging applications, particularly furanoate-based nanocomposites, which have gained a high interest level in research and development in both academia and industries. The monomers utilised for the synthesis of furanoate-based polyesters were derived from lignocellulosic biomass, which is essential for both eco-friendliness and sustainability. Also, these polyesters have a lower carbon footprint compared to fossil-based plastics, contributing to greenhouse gas reduction. The furanoate-based nanocomposites exhibit enhanced performance characteristics, such as high thermal stability, excellent mechanical strength, superior barrier resistance, and good bacteriostatic rate, making them suitable for a wide range of industrial applications, especially for food-packaging applications. This paper reviews the recent trends in the synthesis routes of monomers, such as the various catalytic activities involved in the oxidation of 5(hydroxymethyl)furfural (HMF) into 2,5-furandicarboxylic acid (FDCA) and its ester, dimethyl furan-2,5-dicarboxylate (DMFD). In addition, this review explores the fabrication of different furanoate-based nanocomposites prepared by in situ polymerization, by melt mixing or solvent evaporation methods, and by using different types of nanoparticles to enhance the overall material properties of the resulting nanocomposites. Emphasis was given to presenting the effect of these nanoparticles on the furanoate polyester’s properties. Ključne besede: 2, 5-furandicarboxylic acid, dimethyl furan-2, 5-dicarboxylat, furanoate polyesters, furanoate nanocomposites, thermal properties, mechanical properties, antibacterial properties, sustainable packaging Objavljeno v DKUM: 10.03.2025; Ogledov: 0; Prenosov: 6
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5. Morphological, surface and thermal properties of polylactic acid foils, melamine-etherified resin, and polyethylene terephthalate fabric during (bio)degradation in soilOlivija Plohl, Alen Erjavec, Lidija Fras Zemljič, Alenka Vesel, Maja Čolnik, Mojca Škerget, Yee Van Fan, Lidija Čuček, Gregor Trimmel, Julija Volmajer Valh, 2023, izvirni znanstveni članek Ključne besede: plastic materials, (bio)degradation, soil, surface chemistry, thermal properties, surface zeta potential Objavljeno v DKUM: 28.02.2025; Ogledov: 0; Prenosov: 6
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6. Effect of monomer type on the synthesis and properties of poly(ethylene furanoate)Johan Stanley, Zoi Terzopoulou, Panagiotis A. Klonos, Alexandra Zamboulis, Eleftheria Xanthopoulou, Savvas Koltsakidis, Dimitrios Tzetzis, Lidija Fras Zemljič, Dimitra A. Lambropoulou, Apostolos Kyritsis, George Z. Papageorgiou, Dimitrios Bikiaris, 2023, izvirni znanstveni članek Opis: This work aimed to produce bio-based poly(ethylene furanoate) (PEF) with a high molecular weight using 2,5-furan dicarboxylic acid (FDCA) or its derivative dimethyl 2,5-furan dicarboxylate (DMFD), targeting food packaging applications. The effect of monomer type, molar ratios, catalyst, polycondensation time, and temperature on synthesized samples’ intrinsic viscosities and color intensity was evaluated. It was found that FDCA is more effective than DMFD in producing PEF with higher molecular weight. A sum of complementary techniques was employed to study the structure– properties relationships of the prepared PEF samples, both in amorphous and semicrystalline states. The amorphous samples exhibited an increase in glass transition temperature of 82–87 ◦C, and annealed samples displayed a decrease in crystallinity with increasing intrinsic viscosity, as analyzed by differential scanning calorimetry and X-ray diffraction. Dielectric spectroscopy showed moderate local and segmental dynamics and high ionic conductivity for the 2,5-FDCA-based samples. The spherulite size and nuclei density of samples improved with increased melt crystallization and viscosity, respectively. The hydrophilicity and oxygen permeability of the samples were reduced with increased rigidity and molecular weight. The nanoindentation test showed that the hardness and elastic modulus of amorphous and annealed samples is higher at low viscosities due to high intermolecular interactions and degree of crystallinity. Ključne besede: bio-based polymers, poly(ethylene furanoate), polycondensation, thermal properties, mechanical properties, oxygen transmission rates Objavljeno v DKUM: 13.02.2025; Ogledov: 0; Prenosov: 3
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7. Synthesis and study of fully biodegradable composites based on poly(butylene succinate) and biocharKaterina Papadopoulou, Panagiotis A. Klonos, Apostolos Kyritsis, Ondřej Mašek, Christian Wurzer, Konstantinos Tsachouridis, Antonios D. Anastasiou, Dimitrios Bikiaris, 2023, izvirni znanstveni članek Ključne besede: poly(butylene succinate), biochar, biocomposites, thermal properties, thermal conductivity, molecular mobility, mechanical properties, enzymatic hydrolysis Objavljeno v DKUM: 10.04.2024; Ogledov: 200; Prenosov: 15
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8. Ground-sourced energy wells for heating and cooling of buildingsHeinz Brandl, Dietmar Adam, Roman Markiewicz, 2006, izvirni znanstveni članek Opis: Energy wells are thermo-active elements for an economical extraction or storage of ground energy, similar to energy piles and other deep foundation elements also used as heat exchangers. Heating and/or cooling of buildings requires a primary and secondary thermo-active circuit, commonly connected by a heat pump. The paper gives several design aspects of energy wells which can be also used for the design of deep energy foundations. Thermal response tests have proved suitable for the in-situ determination of thermal ground properties required for an optimised design. Moreover, different systems of energy wells are discussed, and a comprehensive pilot research project is described. Ključne besede: energy wells, energy foundations, geothermal geotechnics, geothermal heating/cooling, thermo-active structures, thermal ground properties, field testing Objavljeno v DKUM: 17.05.2018; Ogledov: 1086; Prenosov: 131
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9. Thermal-mechanical sensory properties of hot-air welded textile transmission linesSimona Jevšnik, Li Yi, Junyan Hu, Han Xiao, Wu Xinxing, Anthony Primentas, 2016, izvirni znanstveni članek Opis: Hot air welding technology is one of the new promising techniques for integrating conductive yarns on or into fabrics, besides weaving, knitting, printing, coating or inserting conductive yarns by the sewing and/or embroidery processes. A new issue related to the introduction of hot air welding technology for making e-textile transmission lines, i.e., the mechanical-thermal sensory properties of hot air welded e-textile transmission lines, is investigated in this study. Fabric Touch Tester (FTT) was used to evaluate thermal, compressive and bending properties of hot air welded transmission lines. The results show that the bending of welded fabric increased after hot air welding in both warp and weft directions. Furthermore, the maximum thermal flux and thermal conductivity of welded specimens decreased in comparison to the substrate fabric. Ključne besede: textile transmission lines, hot-air welding, fabric touch tester, conductive yarns, e-textile transmission lines, thermal properties Objavljeno v DKUM: 01.09.2017; Ogledov: 1386; Prenosov: 453
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10. Exergy analysis of a Brayton cycle with variable physical properties and variable composition of working substanceMarija Živić, Antun Galović, Jurij Avsec, Mario Holik, 2016, izvirni znanstveni članek Opis: The exergy analysis of a Brayton cycle is performed in the paper. The four input variables: the ratio of the compressor exit and inlet pressures, the ratio of inlet temperature of gases in turbine and inlet temperature of air in compressor and the isentropic efficiencies of the compressor and turbine are analysed. The temperature ratio is varied in a way that the compressor inlet temperature of air is maintained constant, while the turbine inlet temperature of flue gases is varied from 900 to 1200°C. In the combustion chamber methane is completely combusted with excess air ratio which is determined by the temperature of flue gases at the turbine inlet. The analysis further includes variability of the molar heat capacities of air and flue gases with temperature and variability of their heat capacity ratios. The exergy destruction in turbine, compressor and combustion chamber and also total exergy efficiency of the cycle are considered in the analysis. Ključne besede: Brayton cycle, variable physical properties, variable composition of working substance, maximum work output, maximum thermal efficiency Objavljeno v DKUM: 12.07.2017; Ogledov: 2263; Prenosov: 363
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