TY - JOUR A1 - Schamel, Elisabeth A1 - Bauer, Florian A1 - Schlachter, Herbert A1 - Wehnert, Gerd A1 - Söthje, Dominik T1 - Bio-Based Epoxy Resins Derived from Eugenol with High Glass Transition Temperatures as Substitutes for DGEBA JF - Macromolecular Materials and Engineering N2 - Epoxy resins (EPs) are crucial for high-performance applications like lightweight materials, due to their excellent properties. However, the commonly used diglycidyl ether of bisphenol A (DGEBA) has two major disadvantages: it is synthesized mainly from petrochemicals and includes the health concerning bisphenol A. Eugenol is a bio-based aromatic compound that can be modified into di- or triglycidyl ether. Through investigations four monomers are obtained based on eugenol and crosslinked with two curing agents isophorone diamine and 4,4′-diaminodiphenyl sulfone to compare the properties of the resulting EPs with references containing DGEBA. Using new synthesis routes, the bio-content of the monomers can be increased up to 94 wt%. Intramolecular cyclization occurs if a hydroxy group is in ortho-position to the glycidyl ether group. The crosslinking conditions of the bio-based monomers are comparable to or lower than those of DGEBA. The eugenol-based triglycidyl monomers exhibit very high glass transition temperatures of up to 271 °C, almost 50 °C above the reference value, which can enable their use for lightweight construction such as matrices for fiber-reinforced plastics. The char content of all bio-based EPs after pyrolysis is significantly higher in comparison to the references, which may have a favorable effect on fire resistance. KW - Bio-Based KW - Epoxy Resins KW - Eugenol KW - High Glass Transition Temperatures KW - Substitutes for DGEBA Y1 - 2025 U6 - https://doi.org/10.1002/mame.202400394 SN - 1439-2054 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Schamel, Elisabeth A1 - Wehnert, Gerd A1 - Schlachter, Herbert A1 - Söthje, Dominik T1 - Chemical Recycling of Carbon Fiber Reinforced Epoxy Composites Using Mild Conditions JF - Chemie Ingenieur Technik N2 - AbstractThe increased use of carbon fiber reinforced thermosets generates more waste and end‐of‐life products. However, an efficient recycling method for the expensive carbon fibers has not yet been developed. The selective decomposition of amine‐cured epoxy resin under mild conditions is presented. A two‐step method was investigated to decompose the epoxy resin. The optimum parameters were initially determined using a model compound. By analysis of the reaction products, a cleavage of the C–N bond according to the Cope elimination could be proven. Therefore, the Cope elimination is suggested as the main step of the decomposition of amine‐cured epoxy resins in presence of hydrogen peroxide. By dissolving the resin, it is possible to recover resin‐free fibers with unimpaired mechanical properties. Y1 - 2021 U6 - https://doi.org/10.1002/cite.202100048 SN - 0009-286X SN - 1522-2640 VL - 93 IS - 10 SP - 1619 EP - 1628 PB - Wiley ER - TY - JOUR A1 - Li, Huanyu A1 - Schamel, Elisabeth A1 - Liebscher, Marco A1 - Zhang, Yupeng A1 - Fan, Qingyi A1 - Schlachter, Herbert A1 - Köberle, Thomas A1 - Mechtcherine, Viktor A1 - Wehnert, Gerd A1 - Söthje, Dominik T1 - Recycled carbon fibers in cement-based composites: Influence of epoxide matrix depolymerization degree on interfacial interactions JF - Journal of Cleaner Production N2 - The use of recycled carbon fibers (rCFs) in cement composites is beneficial regarding strength improvements and environmental aspects. In this paper, we present the addition of carbon fibers recovered from reinforced epoxides using hydrogen peroxide (H2O2) to cement-based composites. Two degrees of depolymerization were investigated regarding the physiochemical properties of the fibers and the interfacial interactions. Although regained CFs exhibited a smaller amount of oxygen-containing groups on the surface than virgin CF (vCF), they exhibit better adhesion and pullout resistance, as proved in single-fiber pullout tests from a cementitious matrix. The subsequent incorporation of recovered CFs into cement-based composites resulted in a pronounced increase in flexural and compressive strengths compared with the plain matrices and the cement reinforced with virgin CFs. Furthermore, the rCFs with a higher degree of depolymer-ization showed a better interfacial interaction toward cement matrices and hence also a better reinforcing effect. KW - Recyling KW - Cabon Fibers KW - Cement-based Composites Y1 - 2023 U6 - https://doi.org/10.1016/j.jclepro.2023.137235 SN - 0959-6526 VL - 411 SP - 2 EP - 13 PB - Elsevier BV ER - TY - JOUR A1 - Schamel, Elisabeth A1 - Schlachter, Herbert A1 - Söthje, Dominik A1 - Wehnert, Gerd T1 - Carbonfasern zurückgewinnen BT - Chemisches Recycling von FVK mit Epoxidharzmatrix JF - Kunststoffe N2 - Faserverbundkunststoffe mit Duromermatrix lassen sich bisher nur unzureichend recyceln. Die starke Vernetzung der Duromere steht dem im Wege. Durch eine spezielle organisch-chemische Spaltungsreaktion können Carbonfasern nun jedoch aus Epoxidharz-basierten Faserverbundkunststoffen zurückgewonnen werden. KW - Recyling KW - Carbonfasern KW - Epoxidharz Y1 - 2023 VL - 2023 IS - 2 PB - Carl Hanser Verlag CY - München ER - TY - JOUR A1 - Bauer, Florian A1 - Söthje, Dominik A1 - Schlachter, Herbert A1 - Wehnert, Gerd T1 - Mechanical properties of carbon nanotube (CNT) reinforced polymers using electron‐deficient aromatics as additives JF - Polymer Composites N2 - Abstract In initial experiments the effects of aromatic model substances on carbon nanotube (CNT) dispersions in dimethylformamide (DMF) were investigated. Electron‐deficient aromatics interact strongly with CNTs, causing increased agglomeration and sedimentation. Conversely, electron‐donating aromatics stabilize CNT dispersions in DMF. Polymers with electron‐deficient aromatics, such as polyd initrostyrene (PDNS), exhibit a concentration‐dependent effect: low concentrations lead to stabilization of dispersions, while higher concentrations lead to sedimentation. This suggests that such polymers can enhance attraction between the matrix of CNT‐reinforced polymers as well as stabilize the dispersed CNTs. Polycarbonate, modified with polydinitrocarbonate (PDNC) and reinforced with CNTs showed improved mechanical properties. The addition of 6 wt.% CNTs and 6 wt.% PDNC resulted in a notable improvement with a 22% increase in tensile strength, a 29% increase in flexural strength, a 39% increase in Young's modulus and a 47% increase in flexural modulus. This enhancement resulted in an overall mechanical performance comparable to the high‐performance polymer polyetherimide. However, there must be noted, that the addition of PDNC increases the CNT particle size, which can negatively affect mechanical properties. The results highlight the additive's dual role in enhancing adhesive interactions while potentially increasing CNT agglomerate sizes.Highlights Interactions of CNTs dispersed in DMF and various aromatics were investigated. Polydinitrocarbonate (PDNC) was synthesized as a new additive for CNT‐composites. Polycarbonate/CNT‐composites were obtained using extrusion. Test specimens with CNT contents up to 6 wt.% were obtained. Mechanical properties of polycarbonate reached the level of polyetherimide. KW - carbon nanotubes KW - reinforced polymers KW - electron-deficient aromatics Y1 - 2024 U6 - https://doi.org/https://doi.org/10.1002/pc.28695 SN - 0272-8397 VL - 2024 SP - 1 EP - 16 PB - Wiley ER - TY - JOUR A1 - Maldonado, Alba A1 - Aguilar, Tomas A1 - Hauser, Carolin A1 - Wehnert, Gerd A1 - Söthje, Dominik A1 - Schlachter, Herbert A1 - Torres, Alejandra A1 - Bruna, Julio A1 - Valenzuela, Ximena A1 - Rodríguez-Mercado, Francisco T1 - Ethylene Scavenging Films Based on Ecofriendly Plastic Materials and Nano-TiO2: Preparation, Characterization, and In Vivo Evaluation JF - Polymers N2 - It is known that ethylene plays an important role in the quality characteristics of fruits, especially in storage. To avoid the deterioration of fruits caused by ethylene, titanium dioxide (TiO2) has been used due to its photocatalytic capacity. The aim of this study was to develop films based on two types of biopolymers, Mater-Bi (MB) and poly-lactic acid (PLA), with nanoparticles of TiO2 and to determine their ethylene removal capacity and its application in bananas. First, the films were fabricated through an extrusion process with two different concentrations of TiO2 (5 and 10% w/w). Then, the films were characterized by their structural (FTIR), morphological (SEM), thermal (DSC and TGA), dynamic (DMA), barrier, and mechanical properties. The ethylene removal capacities of the samples were determined via gas chromatography and an in vivo study was also conducted with bananas for 10 days of storage. Regarding the characterization of the films, it was possible to determine that there was a higher interaction between PLA with nano-TiO2 than MB; moreover, TiO2 does not agglomerate and has a larger contact surface in PLA films. Because of this, a higher ethylene removal was also shown by PLA, especially with 5% TiO2. The in vivo study also showed that the 5% TiO2 films maintained their quality characteristics during the days in storage. For these reasons, it is possible to conclude that the films have the capacity to remove ethylene. Therefore, the development of TiO2 films is an excellent alternative for the preservation of fresh fruits. KW - ethylene removers; titanium dioxide; eco-friendly films; shelf life Y1 - 2024 U6 - https://doi.org/10.3390/polym16060853 SN - 2073-4360 VL - 16 IS - 6 PB - MDPI AG ER - TY - JOUR A1 - Schamel, Elisabeth A1 - Wehnert, Gerd A1 - Söthje, Dominik T1 - New isoeugenol-derived monomers for the preparation of bio-based epoxy resins JF - European Polymer Journal KW - Bio-Based; Epoxy Resins; Isoeugenol; High Glass Transition Temperatures; Substitutes for DGEBA Y1 - 2025 U6 - https://doi.org/10.1016/j.eurpolymj.2025.114263 VL - 239 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Söthje, Dominik A1 - Wehnert, Gerd A1 - Schamel, Elisabeth A1 - Bauer, Florian A1 - Schlachter, Herbert T1 - Nachhaltig und sicher fliegen - nur eine Zukunftsfantasie? BT - Neuartige Materialien zur Ressourcenschonung in der Luftfahrt JF - OHM Journal N2 - Flugreisen und Luftverkehr sind brennende Themen, wenn es um den ökologischen Fußabdruck geht. Damit beschäftigt sich das Forschungsteam um Prof. Dr. Gerd Wehnert und Prof. Dr.-Ing. Dominik Söthje von der Fakultät Angewandte Chemie. In ihrem Projekt bio-Lufa entwickelt es Faserverbundwerkstoffe auf Grundlage von nachwachsenden Rohstoffen für die Luftfahrt. Y1 - 2022 VL - 2022 IS - 2 SP - 66 EP - 69 PB - Technische Hochschule Nürnberg CY - Nürnberg ER - TY - JOUR A1 - Wehnert, Gerd A1 - Söthje, Dominik A1 - Schlachter, Herbert A1 - Bauer, Florian T1 - C-Mat – Cabon-nanoverstärkte Kunststoffmaterialien JF - Vorlaufforschung 2022 N2 - In diesem Vorlaufforschungsprojekt sollen kommerzielle Carbon Nanotubes (CNTs), die als Agglomeratpulver anfallen, durch geeignete Additive funktionalisiert und vereinzelt werden, um sie in eine Epoxidharzmatrix einzubetten. Die CNTs wurden in Lösungen verschiedener aromatischer Moleküle mittels Ultraschallbad dispergiert und die Partikelgrößenverteilung durch Lichtstreuung bestimmt. Es ließ sich eine partielle Verschiebung der Partikelgrößen durch die Einwirkung der Additive zu kleineren Durchmessern beobachten. Aufbauend auf den Ergebnissen wurden die CNTs in Lösung mit aromatischen Molekülen funktionalisiert und anschließend durch ein Dreiwalzwerk in ein Epoxidharz eingearbeitet. Die hergestellten Komposite wurden mechanisch geprüft, eine Steigerung der Festigkeit war aber bislang nicht zu beobachten. Wir vermuten, dass die Auflösung der CNT-Knäuel und die Verhinderung der CNT-Re-Agglomeration entscheidend für die Wirksamkeit der Verstärkung ist. Y1 - 2023 UR - urn:nbn:de:bvb:92-opus4-46790 SN - 1867-4585 VL - 2022 SP - 125 EP - 142 PB - TH Nürnberg CY - Nürnberg ER - TY - GEN A1 - Bauer, Florian A1 - Söthje, Dominik A1 - Wehnert, Gerd T1 - From Basil to Bio-Epoxy: Estragole-Based Resin with High Performance BT - - T2 - In: 19th Biennial Bayreuth Polymer Symposium, Overview of posters and poster abstracts Y1 - 2025 SP - 96 ER -