{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,3]],"date-time":"2026-09-03T10:15:12Z","timestamp":1788430512908,"version":"build-2803163510"},"reference-count":28,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2026,9,3]],"date-time":"2026-09-03T00:00:00Z","timestamp":1788393600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Ministry of Research, Innovation and Digitalization of Romania","award":["PN 23 17 04 02"],"award-info":[{"award-number":["PN 23 17 04 02"]}]},{"name":"Ministry of Research, Innovation and Digitalization of Romania","award":["PN 23 17 04 01"],"award-info":[{"award-number":["PN 23 17 04 01"]}]},{"DOI":"10.13039\/501100006595","name":"UEFISCDI","doi-asserted-by":"publisher","award":["PN-III-P2-2.1-PED-2021-3408"],"award-info":[{"award-number":["PN-III-P2-2.1-PED-2021-3408"]}],"id":[{"id":"10.13039\/501100006595","id-type":"DOI","asserted-by":"publisher"}]},{"award":["PN-III-P2-2.1-PED-2021-3408"],"award-info":[{"award-number":["PN-III-P2-2.1-PED-2021-3408"]}],"id":[{"id":"https:\/\/ror.org\/01q7jq182","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Polymers"],"abstract":"<jats:p>Carbon-fiber-reinforced polymer (CFRP) composites fabricated with bio-based epoxy resins represent a promising approach for sustainable lightweight structures produced by out-of-autoclave (OoA) technologies. The curing schedule influences the state of the epoxy matrix and, consequently, can affect the fiber\u2013matrix interaction and laminate performance. This study investigates the effect of practical curing conditions on 2 \u00d7 2 twill woven carbon fiber laminates fabricated by vacuum infusion using a commercially available bio-based epoxy resin IB2. The manufacturer\u2019s recommended room-temperature conditions (25 \u00b0C for 24 h) were compared with accelerated mold heating schedules at 40, 50, 60, and 70 \u00b0C for 12 h. The laminates were characterized by three-point tensile and flexural tests, heat deflection temperature (HDT) measurements, differential scanning calorimetry (DSC), and SEM fractography. The tensile response showed limited sensitivity to the investigated curing conditions, with mean tensile strengths ranging from 634.01 to 672.95 MPa; T60 exhibited the highest mean numerical tensile strength (672.95 \u00b1 53.60 MPa) and tensile modulus (53.39 \u00b1 11.53 GPa), although the differences were small relative to the experimental spread. In contrast, the flexural response was more sensitive to the processing conditions. T70 exhibited the highest average flexural strength (980.60 \u00b1 129.03 MPa), strain at maximum flexural stress, and strain energy density to maximum stress (8.75 \u00b1 1.89 MJ\/m3). The heat deflection temperature (HDT) systematically increased from 65.20 \u00b0C for T25 to 85.83 \u00b0C for T70. DSC revealed clear differences in the calorimetric response after curing during the first heating cycle, while the glass transition temperatures at the middle of the second heating occupied a relatively narrow range of 80.9\u201385.6 \u00b0C. SEM fractography revealed mixed tensile failure mechanisms related to fibers, matrix, and interface under all curing conditions. Overall, the results demonstrate that accelerated 12 h heated mold programs can reduce cure time while maintaining tensile performance generally comparable to the 24 h room-temperature IB2 reference condition and providing higher average flexural performance and thermal deformation resistance under load. These findings establish processing\u2013property relationships relevant to the development of biomass-based CFRP OoA laminates for lightweight aerospace applications.<\/jats:p>","DOI":"10.3390\/polym18172154","type":"journal-article","created":{"date-parts":[[2026,9,3]],"date-time":"2026-09-03T09:20:43Z","timestamp":1788427243000},"page":"2154","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Effects of Curing Schedules on Carbon-Fiber-Reinforced Laminates with a Bio-Based Epoxy Matrix"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0009-0008-2696-2917","authenticated-orcid":false,"given":"Larisa-Anda","family":"Stroe","sequence":"first","affiliation":[{"name":"Department of Aerospace Sciences, National University of Science and Technology POLITEHNICA Bucharest, Splaiul Independen\u0163ei 313, 060042 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Daniel-Eugeniu","family":"Crunteanu","sequence":"additional","affiliation":[{"name":"Department of Aerospace Sciences, National University of Science and Technology POLITEHNICA Bucharest, Splaiul Independen\u0163ei 313, 060042 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"funding-acquisition","vocabulary":"credit"},{"role":"conceptualization","vocabulary":"credit"},{"role":"resources","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2036-3509","authenticated-orcid":false,"given":"Mihail","family":"Botan","sequence":"additional","affiliation":[{"name":"INCAS\u2014National Institute for Aerospace Research \u201cElie Carafoli\u201d, B-dul Iuliu Maniu 220, 061126 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Adriana","family":"Stefan","sequence":"additional","affiliation":[{"name":"Department of Aerospace Sciences, National University of Science and Technology POLITEHNICA Bucharest, Splaiul Independen\u0163ei 313, 060042 Bucharest, Romania"},{"name":"INCAS\u2014National Institute for Aerospace Research \u201cElie Carafoli\u201d, B-dul Iuliu Maniu 220, 061126 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"George Catalin","family":"Cristea","sequence":"additional","affiliation":[{"name":"Department of Aerospace Sciences, National University of Science and Technology POLITEHNICA Bucharest, Splaiul Independen\u0163ei 313, 060042 Bucharest, Romania"},{"name":"INCAS\u2014National Institute for Aerospace Research \u201cElie Carafoli\u201d, B-dul Iuliu Maniu 220, 061126 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gabriela-Liliana","family":"Stroe","sequence":"additional","affiliation":[{"name":"Department of Aerospace Sciences, National University of Science and Technology POLITEHNICA Bucharest, Splaiul Independen\u0163ei 313, 060042 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,3]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"7741","DOI":"10.1002\/pc.70695","article-title":"A Comprehensive Review of Composite Materials: Current and Future Prospects in Aerospace Applications","volume":"47","author":"Shrivastava","year":"2026","journal-title":"Polym. Compos."},{"key":"ref_2","first-page":"24","article-title":"Advances in Composite Structures: A Systematic Review of Design, Performance, and Sustainability Trends","volume":"1","year":"2024","journal-title":"WAR J. Multidiscip. Bull."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Dalpadulo, E., Russo, M., Gherardini, F., and Leali, F. (2024, January 12). Towards the Design-Driven Carbon Footprint Reduction of Composite Aerospace and Automotive Components: An Overview. Proceedings of the CO2 Reduction for Transportation Systems Conference, Turin, Italy.","DOI":"10.4271\/2024-37-0032"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1989","DOI":"10.1017\/dsd.2020.29","article-title":"Sustainability assessment of composites in aero-engine components","volume":"1","author":"Nylander","year":"2020","journal-title":"Proc. Des. Soc. Des. Conf."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Vedrtnam, A., Negi, H., and Kalauni, K. (2025). Materials and Energy-Centric Life Cycle Assessment for Drones: A Review. J. Compos. Sci., 9.","DOI":"10.3390\/jcs9040169"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"93","DOI":"10.22271\/27078043.2025.v6.i2a.99","article-title":"Environmental Impact of Advanced Composite Materials in Manufacturing Industries","volume":"6","author":"Akter","year":"2025","journal-title":"Int. J. Mech. Therm. Eng."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Boursier Niutta, C., Ciardiello, R., Tridello, A., and Paolino, D.S. (2023). Epoxy and Bio-Based Epoxy Carbon Fiber Twill Composites: Comparison of the Quasi-Static Properties. Materials, 16.","DOI":"10.3390\/ma16041601"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"426","DOI":"10.1021\/acsapm.0c01187","article-title":"Fully Bio-Based Epoxy-Amine Thermosets Reinforced with Recycled Carbon Fibers as a Low Carbon-Footprint Composite Alternative","volume":"3","author":"Mattar","year":"2021","journal-title":"ACS Appl. Polym. Mater."},{"key":"ref_9","unstructured":"Zao, T. (2018). Development and Characterization of Bio-Based Fibre-Reinforced Polymer Composites for Structural Applications in Civil Engineering, Instituto Superior T\u00e9cnico, Universidade de Lisboa."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"9805","DOI":"10.1021\/acssuschemeng.4c02186","article-title":"New Generation of Recyclable High-Performance Biobased Epoxy Thermosets and Composites","volume":"12","author":"Dinu","year":"2024","journal-title":"ACS Sustain. Chem. Eng."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"101353","DOI":"10.1016\/j.progpolymsci.2020.101353","article-title":"Advances in Sustainable Thermosetting Resins: From Renewable Feedstock to High Performance and Recyclability","volume":"113","author":"Liu","year":"2021","journal-title":"Prog. Polym. Sci."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"119","DOI":"10.1080\/09506608.2021.1915936","article-title":"Advances in the Development of Biobased Epoxy Resins: Insight into More Sustainable Materials and Future Applications","volume":"67","author":"Santos","year":"2022","journal-title":"Int. Mater. Rev."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Derradji, M., Mehelli, O., Liu, W., and Fantuzzi, N. (2021). Sustainable and Ecofriendly Chemical Design of High Performance Bio-Based Thermosets for Advanced Applications. Front. Chem., 9.","DOI":"10.3389\/fchem.2021.691117"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"100227","DOI":"10.1016\/j.jalmes.2025.100227","article-title":"Carbon Fibre for Applications in Aerospace: A Review","volume":"12","author":"Mamat","year":"2025","journal-title":"J. Alloys Metall. Syst."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"S\u00f6nmez, M., Pelin, C.-E., Georgescu, M., Pelin, G., Stelescu, M.D., Nituica, M., Stoian, G., Alexandrescu, L., and Gurau, D. (2022, January 26\u201328). Unmanned Aerial Vehicles-Classification, Types of Composite Materials Used in Their Structure and Applications. Proceedings of the CAMS 2022\u20149th International Conference on Advanced Materials and Systems, Bucharest, Romania.","DOI":"10.24264\/icams-2022.I.11"},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Soutis, C. (2019). Aerospace Engineering Requirements in Building with Composites. Polymers Composites in the Aerospace Industry, Woodhead Publishing. [2nd ed.].","DOI":"10.1016\/B978-0-08-102679-3.00001-0"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Kumar, I., Bodavula, A., Kumar, P.P., Subramani, K., Bezawada, S., and Velmurugan, P. (2025). Multimodal Deep Learning for Predictive Analysis of Lightweight Composites in Aircraft Structures. Proceedings of the 2025 10th International Conference on Science Technology, Engineering and Mathematics (ICONSTEM), Chennai, India, 6\u20137 November 2025, IEEE.","DOI":"10.1109\/ICONSTEM65670.2025.11374331"},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Mazlan, N., Chai Hua, T., Sapuan, S.M., and Ilyas, R.A. (2022). Evolution of Aerospace Composite Materials. Advanced Composites in Aerospace Engineering Applications, Springer.","DOI":"10.1007\/978-3-030-88192-4"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Nagaraju, S.B., Priya, H.C., Girijappa, Y.G.T., and Puttegowda, M. (2023). Lightweight and Sustainable Materials for Aerospace Applications. Lightweight and Sustainable Composite Materials: Preparation, Properties and Applications, Woodhead Publishing.","DOI":"10.1016\/B978-0-323-95189-0.00007-X"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"31895","DOI":"10.1007\/s13399-023-04736-2","article-title":"Synthesis and Characterization of Lightweight Unmanned Aerial Vehicle Composite Building Material for Defense Application","volume":"14","author":"Prakash","year":"2024","journal-title":"Biomass Convers. Biorefin."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Liang, J., Liu, L., Qin, Z., Zhao, X., Li, Z., Emmanuel, U., and Feng, J. (2023). Experimental Study of Curing Temperature Effect on Mechanical Performance of Carbon Fiber Composites with Application to Filament Winding Pressure Vessel Design. Polymers, 15.","DOI":"10.3390\/polym15040982"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"153","DOI":"10.1016\/j.eurpolymj.2016.07.014","article-title":"Curing Kinetics and Mechanical Properties of Bio-Based Epoxy Composites Comprising Lignin-Based Epoxy Resins","volume":"82","author":"Ferdosian","year":"2016","journal-title":"Eur. Polym. J."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"114739","DOI":"10.1016\/j.matdes.2025.114739","article-title":"Mechanical Analysis of Unidirectional Glass Fibre Reinforced Epoxy Composite Joints Manufactured by Adhesive Bonding and Co-Curing Techniques","volume":"258","author":"Jiang","year":"2025","journal-title":"Mater. Des."},{"key":"ref_24","unstructured":"(2023). Plastics\u2014Determination of Tensile Properties\u2014Part 4: Test Conditions for Isotropic and Orthotropic Fibre-Reinforced Plastic Composites (Standard No. ISO 527-4:2023)."},{"key":"ref_25","unstructured":"(1998). Fibre-Reinforced Plastic Composites\u2014Determination of Flexural Properties (Standard No. ISO 14125:1998)."},{"key":"ref_26","unstructured":"(2018). Standard Test Method for Deflection Temperature of Plastics Under Flexural Load in the Edgewise Position (Standard No. ASTM D648-18)."},{"key":"ref_27","unstructured":"(2023). Plastics\u2014Differential Scanning Calorimetry (DSC)\u2014Part 1: General Principles (Standard No. ISO 11357-1:2023)."},{"key":"ref_28","unstructured":"(2020). Plastics\u2014Differential Scanning Calorimetry (DSC)\u2014Part 2: Determination of Glass Transition Temperature and Step Height (Standard No. ISO 11357-2:2020)."}],"container-title":["Polymers"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2073-4360\/18\/17\/2154\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,3]],"date-time":"2026-09-03T09:28:28Z","timestamp":1788427708000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2073-4360\/18\/17\/2154"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,9,3]]},"references-count":28,"journal-issue":{"issue":"17","published-online":{"date-parts":[[2026,9]]}},"alternative-id":["polym18172154"],"URL":"https:\/\/doi.org\/10.3390\/polym18172154","relation":{},"ISSN":["2073-4360"],"issn-type":[{"value":"2073-4360","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,9,3]]}}}