{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,13]],"date-time":"2026-10-13T14:00:47Z","timestamp":1791900047745,"version":"4.3.4"},"reference-count":30,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2025,2,3]],"date-time":"2025-02-03T00:00:00Z","timestamp":1738540800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"EsSENce Cost Action CA19118"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Polymers"],"abstract":"<jats:p>Carbon fiber-reinforced polymers (CFRPs) are widely used in high-performance applications, but their inherent brittleness and susceptibility to impact damage remain critical challenges. This study investigated the effect of core\u2013shell rubber (CSR) particles as impact modifiers on the mechanical properties of CFRPs and evaluated patch repair techniques for damaged CFRP panels. Mechanical tests, including flexural, tensile, short-beam, fracture toughness, and impact tests, were conducted on reference and CSR-modified specimens to assess their structural performance. The CSR-modified samples demonstrated significant improvements in energy absorption and fracture toughness, with a 50% increase in impact strength and up to 181% improvement in absorbed energy during Mode I fracture testing. However, slight reductions in flexural and tensile strengths were observed due to the softening effect of CSR particles. Fracture surface analysis revealed distinct failure mechanisms, with Scanning Electron Microscopy imaging showing consistent fiber pull-out behavior in tensile and flexural tests, but more stable delamination propagation in CSR-modified specimens during short-beam shear tests. Patch repair effectiveness was assessed through drop-weight impact tests on damaged panels repaired with patches containing CSRs of two thicknesses. Patches of equal thickness to the damaged panel successfully restored structural integrity and enhanced energy absorption by 37% compared with the reference samples, while thinner patches (as a suggestion to reduce production costs) failed to withstand impact loads effectively. Non-destructive testing (NDT) via ultrasonic C-scans confirmed reduced delamination and damage depth in CSR-modified repaired panels, validating the toughening effect of CSR particles. These findings demonstrate the potential of CSR-modified resins to improve CFRPs\u2019 performance and provide effective repair solutions for extending the service life of damaged composite structures, rendering them especially suitable for applications demanding high damage tolerance and durability, including aerospace structures, automotive body panels, and energy-absorbing crash components.<\/jats:p>","DOI":"10.3390\/polym17030407","type":"journal-article","created":{"date-parts":[[2025,2,3]],"date-time":"2025-02-03T12:18:56Z","timestamp":1738585136000},"page":"407","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Enhancing Carbon Fiber-Reinforced Polymers\u2019 Performance and Reparability Through Core\u2013Shell Rubber Modification and Patch Repair Techniques"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6204-6931","authenticated-orcid":false,"given":"Dionisis","family":"Semitekolos","sequence":"first","affiliation":[{"name":"RNANO Lab\u2014Research Lab of Advanced, Composite, Nanomaterials and Nanotechnology, School of Chemical Engineering, National Technical University of Athens, 9 Heroon Polytechneiou st., Zografos, GR-15773 Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0000-4383-4847","authenticated-orcid":false,"given":"Sofia","family":"Terzopoulou","sequence":"additional","affiliation":[{"name":"RNANO Lab\u2014Research Lab of Advanced, Composite, Nanomaterials and Nanotechnology, School of Chemical Engineering, National Technical University of Athens, 9 Heroon Polytechneiou st., Zografos, GR-15773 Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1367-7603","authenticated-orcid":false,"given":"Costas","family":"Charitidis","sequence":"additional","affiliation":[{"name":"RNANO Lab\u2014Research Lab of Advanced, Composite, Nanomaterials and Nanotechnology, School of Chemical Engineering, National Technical University of Athens, 9 Heroon Polytechneiou st., Zografos, GR-15773 Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,2,3]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1173","DOI":"10.1007\/s42823-022-00358-2","article-title":"A review on carbon fiber-reinforced hierarchical composites: Mechanical performance, manufacturing process, structural applications and allied challenges","volume":"32","author":"Sayam","year":"2022","journal-title":"Carbon Lett."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"644","DOI":"10.1016\/j.carbon.2021.10.061","article-title":"Strategies for the production of PAN-Based carbon fibers with high tensile strength","volume":"186","author":"Jang","year":"2022","journal-title":"Carbon"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Butenegro, J.A., Bahrami, M., Abenojar, J., and Mart\u00ednez, M.\u00c1. 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