TY - JOUR AU - Pomázi, Ákos AU - Magyar, Gergely AU - Toldy, Andrea TI - Methods for predicting the fire behaviour of fibre reinforced thermoset composites JF - POLYMER DEGRADATION AND STABILITY J2 - POLYM DEGRAD STABIL VL - 245 PY - 2026 PG - 11 SN - 0141-3910 DO - 10.1016/j.polymdegradstab.2025.111857 UR - https://m2.mtmt.hu/api/publication/36849868 ID - 36849868 N1 - This research was funded by the National Research, Development and Innovation Office (NKFIH K142517 and STARTING 150473). Project no TKP-6–6/PALY-2021 has been implemented with the support provided by the Ministry of Culture and Innovation of Hungary from the National Research, Development and Innovation Fund, financed under the TKP2021-NVA funding scheme. Ákos Pomázi is thankful for the support of the Michelberger Master Prize of the Hungarian Academy of Engineering. This research was partly supported by the Doctoral Excellence Fellowship Programme (DCEP) is funded by the National Research Development and Innovation Fund of the Ministry of Culture and Innovation and the Budapest University of Technology and Economics, under a grant agreement with the National Research, Development and Innovation Office. AB - Destructive tests are typically used to evaluate the fire performance of polymers and their composites, implying high material costs and long testing times. Developing numerical models to predict flammability requires advanced mathematical expertise, IT resources, and realistic input parameters. In this study, we aimed to predict the key flammability parameters based on the chemical structure of the resin matrices and fibre content of composites, providing a potential alternative to costly experimental methods. We employed Random Forest Classifier (RFC), XGBoost algorithms, and an artificial neural network (ANN) model to predict key combustion parameters: peak heat release rate (pHRR), time to ignition (TTI), total heat release (THR) and the char residue (CR) solely based on chemical structure of the epoxy matrix and fibre content of the composite. After making the predictions, we assessed the performance of the models using consistent statistical indicators (mean absolute error (MAE), mean square error (MSE), and the determination parameter (R2)). LA - English DB - MTMT ER - TY - JOUR AU - Pomázi, Ákos AU - Kovács, Zsófia AU - Szolnoki, Beáta AU - Szebényi, Gábor AU - Toldy, Andrea TI - Development of Flame Retarded Battery Casings Using Glass Fiber-Reinforced Epoxy Resin JF - POLYMER COMPOSITES J2 - POLYM COMPOSITE VL - Early View PY - 2026 PG - 15 SN - 0272-8397 DO - 10.1002/pc.71537 UR - https://m2.mtmt.hu/api/publication/37476131 ID - 37476131 N1 - First published: 18 August 2026 Funding Agency and Grant Number: HORIZON EUROPE Framework Programme [101005435]; National Research, Development and Innovation Office [142517, 142540, 150473]; Magyar Tudomnyos Akadmia, Jnos Bolyai Scholarship Funding text: This work was supported by National Research, Development and Innovation Office (grant nos. 142517, 142540, 150473), HORIZON EUROPE Framework Programme (grant no. 101005435), Magyar Tudomanyos Akademia, Janos Bolyai Scholarship. AB - This study investigates the development of glass fiber-reinforced epoxy resin composites with enhanced fire performance for application in electric vehicle battery casings. A low-viscosity epoxy system incorporating phosphorus-, inorganic-, and nitrogen-based (PIN) flame retardants was designed, with particular focus on achieving synergistic effects between ammonium polyphosphate (APP), titanium dioxide (TiO2) and talcum. A multi-stage evaluation strategy was applied, including preliminary screening (TGA, LOI, UL-94, DSC, DMA), followed by detailed characterization of rheological behavior, fire performance under simulated real-fire conditions (cone calorimetry, glow wire flammability index), and mechanical, electrical, and microstructural properties of the resulting composites. The combination of APP and TiO2 exhibited a pronounced synergistic effect, enabling UL-94 V-0 classification in reinforced composites at 4 mm thickness. Cone calorimetry revealed a 53% reduction in peak heat release rate, attributed to enhanced char formation and stabilization of the protective layer. Importantly, the incorporation of solid flame retardants with appropriate morphology did not compromise the glass transition temperature (T-g > 135 degrees C) and resulted in only minor reductions in flexural properties (< 10%), while electrical resistivity remained unchanged. The results demonstrate that the appropriate selection and combination of solid flame retardants enables the decoupling of fire performance from thermomechanical degradation, providing a viable pathway for the development of multifunctional composite materials for fire-safe battery enclosure applications. LA - English DB - MTMT ER - TY - JOUR AU - Szpecht, Andrea AU - Zielinski, Dawid AU - Ochota, Kamil AU - Pomázi, Ákos AU - Toldy, Andrea TI - One Core, Many Cures: Quantitative Design Rules for Ionic Liquid Epoxy Curing Agents JF - MACROMOLECULES J2 - MACROMOLECULES PY - 2026 PG - 12 SN - 0024-9297 DO - 10.1021/acs.macromol.6c01435 UR - https://m2.mtmt.hu/api/publication/37547550 ID - 37547550 N1 - Funding Agency and Grant Number: National Science Centre (Poland) [2024/55/B/ST11/03034]; Research, Development and Innovation Office of Hungary [K142517, 150473] Funding text: This work was supported by the National Science Centre (Poland) [grant number 2024/55/B/ST11/03034]. This research was funded by the National Research, Development and Innovation Office (NKFIH K142517 and STARTING 150473) of Hungary. The authors acknowledge the assistance of Leo Gonton, a student of the Programme Grande Ecole at Arts et Metiers ParisTech, who carried out his internship at Budapest University of Technology and Economics, and contributed to performing the DSC measurements. AB - Epoxy formulations containing a 20-member library of 1-methylimidazolium dicyanamide ionic liquids showed systematic N-substituent-dependent differences in thermal curing behavior. The library comprised alkyl, unsaturated, polar-functionalized, ether/silyl-containing, and aromatic/bulky substituents. Principal component analysis combined five cation descriptors- topological polar surface area, molar refractivity, fraction of sp3-hybridized carbon atoms, number of rotatable bonds, and cLogP - with four differential scanning calorimetry (DSC) parameters (T p, Delta H c, T g, Delta T g). Across the library, T p ranged 120.8-172.5 degrees C, T g 46.0-98.6 degrees C, and Delta H c 141-620 J g-1. PC1 (43.04%) described a polarity-flexibility dimension associated with temperature-related parameters, whereas PC2 (21.85%) was associated primarily with curing enthalpy. PC1 decreased approximately linearly across the C2-C16 alkyl series. Three low-enthalpy systems occupied distinct multivariate regions consistent with possible steric limitation, amide-mediated self-association, or trimethoxysilyl-group reactions. The resulting map provides quantitative within-library design rules under the investigated formulation, fixed molar ionic-pair content, and DSC conditions. LA - English DB - MTMT ER - TY - JOUR AU - Toldy, Andrea AU - Poór, Dániel István AU - Szolnoki, Beáta AU - Geier, Norbert AU - Pomázi, Ákos TI - Synergistic flame retardancy of carbon fibre-reinforced polyimine vitrimer composites via vitrimer-based intumescent coating JF - COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING J2 - COMPOS PART A-APPL S VL - 198 PY - 2025 PG - 13 SN - 1359-835X DO - 10.1016/j.compositesa.2025.109135 UR - https://m2.mtmt.hu/api/publication/36212418 ID - 36212418 N1 - This research was funded by the National Research, Development and Innovation Office (NKFIH K142517, STARTING 150473). Project no. TKP-6-6/PALY-2021 has been implemented with the support provided by the Ministry of Culture and Innovation of Hungary from the National Research, Development and Innovation Fund, financed under the TKP2021-NVA funding scheme. This research has been implemented with the support provided by the Ministry of Culture and Innovation of Hungary from the National Research, Development and Innovation Fund, financed under the EKÖP-24-3-BME-251 funding scheme. This research was partly supported by the János Bolyai Research Scholarship of the Hungarian Academy of Sciences No. BO/00508/22/6 and BO/00980/23/7. AB - We developed sustainable, recyclable carbon fibre-reinforced polyimine vitrimer composites with enhanced flame retardancy via a combination of resorcinol bis(diphenyl phosphate) (RDP) in the matrix and a 10 %P ammonium polyphosphate (APP) intumescent coating, offering a promising alternative to conventional epoxy systems for advanced applications. Fire performance was evaluated using Limiting Oxygen Index (LOI), UL94, and mass loss calorimetry (MLC) tests. The APP coating acted via a condensed‐phase mechanism, forming a dense, phosphorus oxide‐rich char that reduced the peak heat release rate (pHRR) from 289 kW/m2 to 126 kW/m2—the lowest observed among the tested formulations. Scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM‑EDS) analysis revealed significant phosphorus enrichment in the outer char layer and, notably, an increased phosphorus content in the inner char when RDP was incorporated into the matrix. This synergistic effect indicates that RDP’s gas‐phase action effectively complemented APP’s condensed‐phase mechanism, further enhancing LOI, extending time to ignition (TTI), and reducing total heat release (THR), significantly improving overall fire resistance. Although benchmark epoxy composites exhibited higher tensile strengths, the vitrimer systems maintained competitive mechanical properties alongside superior recyclability, the ability to apply the intumescent coating via hot pressing, and intrinsic repairability. Overall, the dual-action flame retardant strategy achieved by combining RDP and APP significantly improved fire performance, demonstrating the potential of these advanced composites for multifunctional material applications. LA - English DB - MTMT ER - TY - JOUR AU - Toldy, Andrea AU - Poór, Dániel István AU - Geier, Norbert AU - Pomázi, Ákos TI - Recent advances and challenges in the mechanical and chemical recycling of vitrimers and fibre-reinforced vitrimer composites: A review JF - COMPOSITES PART B-ENGINEERING J2 - COMPOS PART B-ENG VL - 306 PY - 2025 PG - 29 SN - 1359-8368 DO - 10.1016/j.compositesb.2025.112760 UR - https://m2.mtmt.hu/api/publication/36235577 ID - 36235577 N1 - This research was funded by the National Research, Development and Innovation Office (NKFIH K142517 and STARTING 150473). Project no. TKP-6-6/PALY-2021 has been implemented with the support provided by the Ministry of Culture and Innovation of Hungary from the National Research, Development and Innovation Fund, financed under the TKP2021-NVA funding scheme. This research has been implemented with the support provided by the Ministry of Culture and Innovation of Hungary from the National Research, Development and Innovation Fund, financed under the EKÖP-24-3-BME-251 and EKÖP-24-4-II-BME-157 funding schemes. Á.P. thanks for the support of the Michelberger Master Prize of the Hungarian Academy of Engineering. AB - Vitrimers, a class of covalent adaptable networks, have emerged as a promising alternative to traditional thermoset and thermoplastic polymers, owing to their unique reprocessability and recyclability. This review provides a comprehensive overview of mechanical and chemical recycling methodologies for vitrimers and their fibre-reinforced composites, highlighting recent advancements and innovations in the field. Firstly, the review classifies vitrimers based on their structure and dynamic covalent mechanisms and summarises their main properties. Subsequently, it gives an overview of the conditions and outcomes of both mechanical and chemical recycling processes for vitrimers. Then, after summarising the processing methods of vitrimer composites, it explores mechanical composite recycling techniques, which, while straightforward, often lead to diminished mechanical properties due to fibre length reduction. In contrast, chemical composite recycling methods demonstrate superior potential for preserving fibre integrity and recovering original monomers for closed-loop synthesis. Key studies showcasing successful recycling processes are discussed, underscoring the importance of developing closed-loop systems to enhance sustainability in material applications. Ultimately, this review aims to highlight the critical advancements in recycling strategies for vitrimers, positioning them as a vital component of sustainable composite material development. LA - English DB - MTMT ER - TY - JOUR AU - Pomázi, Ákos AU - Poór, Dániel István AU - Geier, Norbert AU - Toldy, Andrea TI - Optimising Recycling Processes for Polyimine-Based Vitrimer Carbon Fibre-Reinforced Composites: A Comparative Study on Reinforcement Recovery and Material Properties JF - MATERIALS J2 - MATERIALS VL - 17 PY - 2024 IS - 10 PG - 15 SN - 1996-1944 DO - 10.3390/ma17102372 UR - https://m2.mtmt.hu/api/publication/34966362 ID - 34966362 N1 - Export Date: 10 June 2024 Correspondence Address: Toldy, A.; Department of Polymer Engineering, Műegyetem rkp. 3, Hungary; email: atoldy@edu.bme.hu Funding details: Nemzeti Kutatási, Fejlesztési és Innovaciós Alap, NKFIA Funding details: Nemzeti Kutatási Fejlesztési és Innovációs Hivatal, NKFIH, ÚNKP-23-5-BME-417, ÚNKP-23-3-II-BME-227, ÚNKP-23-5-BME-409, K142517 Funding details: Nemzeti Kutatási Fejlesztési és Innovációs Hivatal, NKFIH Funding details: Magyar Tudományos Akadémia, MTA, BO/00508/22/6, BO/00980/23/7 Funding details: Magyar Tudományos Akadémia, MTA Funding text 1: Project no. TKP-6-6/PALY-2021 has been implemented with the support provided by the Ministry of Culture and Innovation of Hungary from the National Research, Development and Innovation Fund, financed under the TKP2021-NVA funding scheme. This research was funded by the National Research, Development and Innovation Office (NKFIH K142517). This research has been implemented with the support of the 2021-1.2.4-T\\u00C9T-2021-00050, which encourages scientific and technological cooperation between USA and Hungary. Support from the \\u00DANKP-23-3-II-BME-227, \\u00DANKP-23-5-BME-409 and \\u00DANKP-23-5-BME-417 New National Excellence Program of the Ministry for Culture and Innovation from the source of the National Research, Development and Innovation Fund is acknowledged. This research was partly supported by the J\\u00E1nos Bolyai Research Scholarship of the Hungarian Academy of Sciences No. BO/00508/22/6 and No. BO/00980/23/7. \\u00C1.P. thanks the support of the Michelberger Master Prize of the Hungarian Academy of Engineering. AB - We investigated the recycling process of carbon fibre-reinforced polyimine vitrimer composites and compared composites made from virgin and recycled fibres. The vitrimer matrix consisted of a two-component polyimine-type vitrimer system, and as reinforcing materials, we used nonwoven felt and unidirectional carbon fibre. Various diethylenetriamine (DETA) and xylene solvent ratios were examined to find the optimal dissolution conditions. The 20:80 DETA–xylene ratio provided efficient dissolution, and the elevated temperature (80 °C) significantly accelerated the process. Scaling up to larger composite structures was demonstrated. Scanning electron microscopy (SEM) confirmed effective matrix removal, with minimal residue on carbon fibre surfaces and good adhesion in recycled composites. The recycled nonwoven composite exhibited a decreased glass transition temperature due to the residual solvents in the matrix, while the UD composite showed a slight increase. Dynamic mechanical analysis on the recycled composite showed an increased storage modulus for nonwoven composites at room temperature and greater resistance to deformation at elevated temperatures for the UD composites. Interlaminar shear tests indicated slightly reduced adhesion strength in the reprocessed composites. Overall, this study demonstrates the feasibility of recycling vitrimer composites, emphasising the need for further optimisation to ensure environmental and economic sustainability while mitigating residual solvent and matrix effects. © 2024 by the authors. LA - English DB - MTMT ER - TY - JOUR AU - Poór, Dániel István AU - Tobey, Marina AU - Taynton, Philip AU - Pomázi, Ákos AU - Toldy, Andrea AU - Geier, Norbert TI - A comparative machinability analysis of polyimine vitrimer, epoxy and polycarbonate polymers through orthogonal machining experiments JF - INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY J2 - INT J ADV MANUFACT TECHNOL VL - 131 PY - 2024 SP - 1361 EP - 1376 PG - 16 SN - 0268-3768 DO - 10.1007/s00170-024-13087-9 UR - https://m2.mtmt.hu/api/publication/34565460 ID - 34565460 N1 - Department of Manufacturing Science and Engineering, Faculty of Mechanical Engineering, Budapest University of Technology and Economics, Műegyetem Rkp. 3, Budapest, 1111, Hungary MTA-BME Lendület Sustainable Polymers Research Group, Műegyetem Rkp. 3, Budapest, 1111, Hungary Mallinda Inc, Denver, CO 80229, United States Department of Polymer Engineering, Faculty of Mechanical Engineering, Budapest University of Technology and Economics, Műegyetem Rkp. 3, Budapest, 1111, Hungary Export Date: 19 February 2024 CODEN: IJATE Correspondence Address: Geier, N.; Department of Manufacturing Science and Engineering, Műegyetem Rkp. 3, Hungary; email: geier.norbert@gpk.bme.hu Funding details: Magyar Tudományos Akadémia, MTA, BO/00508/22/6 Funding details: Nemzeti Kutatási Fejlesztési és Innovációs Hivatal, NKFI, 2018-1.3.1-VKE-2018-00011, K142517 Funding details: Nemzeti Kutatási, Fejlesztési és Innovaciós Alap, NKFIA Funding text 1: Open access funding provided by Budapest University of Technology and Economics. This research was implemented thanks to the support of the 2021-1.2.4-TÉT-2021-00050, which encourages scientific and technological cooperation between USA and Hungary. Supported by the ÚNKP-22-3-I-BME-92 and ÚNKP-23-5-3502 New National Excellence Program of the Ministry for Culture and Innovation from the source of the National Research, Development and Innovation Fund. This research was partly supported by the János Bolyai Research Scholarship of the Hungarian Academy of Sciences No. BO/00508/22/6. This research was funded by the National Research, Development and Innovation Office (2018-1.3.1-VKE-2018-00011 and NKFIH K142517). AB - End-of-life management of fibre-reinforced thermoset composites is challenging due to the difficult-to-recycle reinforcements and the irreversibly polymerised thermoset matrix; therefore, researchers proposed the vitrimers as a sustainable alternative to thermosetting polymers. Although the early results of the material scientists are promising, the machinability of vitrimers has yet to be explored. Therefore, this paper aims to present a comparative machinability study of polyimine vitrimer, pentaerythritol-based epoxy (PER) and polycarbonate polymers through orthogonal machining experiments. Reflecting on the temperature-dependent properties of vitrimers, the starting temperature of the cutting tool was varied between room temperature and an elevated temperature above 155 °C. The cutting tool was heated by a 2000-W hot air gun until the surface temperature of the cutting tool, monitored by a VariocamHD thermographic IR camera (with Jenoptik IR 1.0/60 LW lens) and checked by a Fluke 51 II thermometer with a type K thermocouple, was permanently above 155 °C for 5 min. The cutting force was measured by a Kistler 9257B dynamometer, and the machined surface was characterised by a Mitutoyo Surftest SJ-400 surface roughness tester and Keyence VHX-5000 (with VH-Z20UT VH lens) microscope. The analysis of variances (ANOVA) results show that the sustainable vitrimer polymer is an appropriate substitute for thermosetting epoxy polymers, especially at low cutting temperatures. LA - English DB - MTMT ER - TY - JOUR AU - Toldy, Andrea AU - Poór, Dániel István AU - Szolnoki, Beáta AU - Devecser, Boglárka AU - Geier, Norbert AU - Pomázi, Ákos TI - Comparative study of flame retardancy in polyimine vitrimers and composites: Evaluating additive and reactive flame retardants acting via gas-, solid-, and combined-phase mechanisms JF - JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY J2 - J MATER SCI TECHNOL VL - 196 PY - 2024 SP - 101 EP - 111 PG - 11 SN - 1005-0302 DO - 10.1016/j.jmst.2024.01.047 UR - https://m2.mtmt.hu/api/publication/34822025 ID - 34822025 N1 - Department of Polymer Engineering, Faculty of Mechanical Engineering, Budapest University of Technology and Economics, H-1111 Budapest, Műegyetem rkp. 3, Hungary MTA-BME Lendület Sustainable Polymers Research Group, Műegyetem rkp. 3, H-1111, Budapest, Hungary Budapest University of Technology and Economics, Faculty of Mechanical Engineering, Department of Manufacturing Science and Engineering, Műegyetem rkp. 3., Budapest 1111, Hungary Department of Organic Chemistry and Technology, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, H-1111 Budapest, Műegyetem rkp. 3, Hungary HUN-REN–BME Research Group for Composite Science and Technology, Műegyetem rkp. 3., H-1111, Budapest, Hungary Export Date: 26 April 2024 CODEN: JSCTE Correspondence Address: Toldy, A.; Department of Polymer Engineering, H-1111 Budapest, Műegyetem rkp. 3, Hungary; email: atoldy@edu.bme.hu AB - We developed flame retarded polyimine type vitrimers and carbon fibre reinforced composites using two additive and a reactive flame retardant containing phosphorus: ammonium polyphosphate (APP), resorcinol bis(diphenyl phosphate) (RDP); and N,N',N’’-tris(2-aminoethyl)-phosphoric acid triamide (TEDAP). We characterised the vitrimer matrix materials by differential scanning calorimetry (DSC), thermal analysis (TGA), limiting oxygen index (LOI), UL-94 test and mass loss calorimetry (MLC), while the vitrimer composites by LOI, UL-94 test, MLC and dynamic mechanical analysis (DMA). We compared the performance of the vitrimer systems to a benchmark pentaerythritol-based aliphatic epoxy resin system (PER). The vitrimer reference had higher thermal stability but lower fire performance than the PER aliphatic reference epoxy. At lower phosphorus content, the vitrimer systems exhibited a melting above their vitrimer transition temperature, which negatively affected their LOI and UL-94 results. From 2% phosphorus content, rapid charring and extinguishing of vitrimers prevented the softening and deforming. The superior performance of these same flame retardants in vitrimer systems could be attributed to the high nitrogen content of imine-based vitrimers in combination with phosphorus flame retardants, exploiting nitrogen-phosphorus synergism. In both matrices, flame retardants with solid phase action lead to better fire performance, while in composites, the lowest peak heat release rates (152 kW/m2 in vitrimer composite) were achieved with RDP acting predominantly in the gas phase, as carbon fibres hindered the intumescent phenomenon. © 2024 LA - English DB - MTMT ER - TY - PAT AU - Toldy, Andrea AU - Kovács, Zsófia AU - Pomázi, Ákos AU - Krecz, Martin AU - Szolnoki, Beáta AU - Marosi, György AU - Hollósi, Ernő TI - Eljárás E-kaprolaktám alapú, in-situ polimerizálható, szerszámban történő bevonatolásra alkalmas égésgátló bevonat előállítására PY - 2024 UR - https://m2.mtmt.hu/api/publication/36211344 ID - 36211344 LA - Hungarian DB - MTMT ER - TY - JOUR AU - Kovács, Zsófia AU - Pomázi, Ákos AU - Toldy, Andrea TI - Development of Multifunctional Flame-Retardant Gel Coatings for Automotive Applications JF - COATINGS J2 - COATINGS VL - 13 PY - 2023 IS - 2 PG - 13 SN - 2079-6412 DO - 10.3390/coatings13020345 UR - https://m2.mtmt.hu/api/publication/33623689 ID - 33623689 N1 - Correspondence Address: Toldy, A.; Department of Polymer Engineering, Műegyetem rkp. 3, Hungary; email: atoldy@edu.bme.hu AB - Due to strict safety regulations, the automotive industry requires an effective reduction of flammability in polymer components. Flame retardants are usually added to the polymer matrix, affecting the viscosity of the matrix. Another possible solution is the application of coatings containing flame retardants, which can additionally ensure good surface quality and protection against external influences. In our research, the flammability of reference and flame retarded gelcoat base materials was investigated using oxygen index (LOI), UL-94, and mass loss type cone calorimetry (MLC) tests. Based on the flammability tests, the best results were obtained with the gelcoat formulation containing 15%P ammonium polyphosphate (APP) and the mixed formulation containing 5%P APP and 5%P resorcinol bis(diphenyl phosphate) (RDP), with a 55% and 64% reduction in the total heat release compared to the reference gelcoat, respectively. The two best-performing coatings were applied to polypropylene (PP) samples. 15%P APP reduced the peak heat release rate of PP by 89% compared to the reference. The gelcoat formulation containing 15%P APP was applied to polyurethane (PUR) automotive components, where the coating reduced the maximum heat release rate by 53% and shifted the time to peak heat release rate by 447 s. LA - English DB - MTMT ER -