{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,8]],"date-time":"2026-01-08T10:43:31Z","timestamp":1767869011416,"version":"3.49.0"},"reference-count":17,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2026,1,6]],"date-time":"2026-01-06T00:00:00Z","timestamp":1767657600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"PRR","award":["C644914747-00000023"],"award-info":[{"award-number":["C644914747-00000023"]}]},{"name":"FCT\u2014Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","award":["UID 00481\/2025"],"award-info":[{"award-number":["UID 00481\/2025"]}]},{"name":"Federal Institute of Bahia"},{"DOI":"10.13039\/501100008532","name":"Federal University of Rio Grande do Norte","doi-asserted-by":"crossref","id":[{"id":"10.13039\/501100008532","id-type":"DOI","asserted-by":"crossref"}]},{"name":"Federal Institute of Rio Grande do Norte"},{"name":"Rio Grande do Norte"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["NDT"],"abstract":"<jats:p>The reuse of industrial residues has gained importance due to environmental and public health concerns associated with improper waste disposal. Steel scale (CDA), a by-product of machining and rolling operations, represents a residue with technological potential for incorporation into polymer composites. This study developed a low-cost and sustainable material by reinforcing an orthophthalic polyester matrix with CDA and systematically evaluated its mechanical, thermal, and structural properties. Four formulations were prepared based on the maximum feasible filler loading: R (pure resin), C1 (50% CDA), C2 (100% CDA), and C3 (150% CDA). Composites were manufactured by cold-press molding under a two-ton compressive load. Characterization included tensile, flexural, and impact testing, thermogravimetric analysis (TGA), thermal conductivity, apparent density, liquid absorption, and morphological assessment by scanning electron microscopy (SEM). CDA incorporation reduced tensile and flexural strength but increased elastic modulus, impact toughness, and thermal conductivity. The C3 composite exhibited the highest thermal stability, retaining more than 50% of its initial mass at 500 \u00b0C. Density and liquid absorption increased proportionally with filler loading, and SEM revealed heterogeneous microstructures with particle agglomeration, sedimentation, and interfacial gaps, explaining the mechanical and thermal trends. The findings demonstrate the feasibility of producing dense and low-cost polyester composites reinforced with steel scale. The structure\u2013property relationships identified in this study establish a foundation for subsequent investigations focusing on additional functional behaviors of this waste-derived material system.<\/jats:p>","DOI":"10.3390\/ndt4010004","type":"journal-article","created":{"date-parts":[[2026,1,6]],"date-time":"2026-01-06T08:42:58Z","timestamp":1767688978000},"page":"4","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Mechanical and Thermal Characterization of Sustainable Polyester Composites Reinforced with Mill Scale"],"prefix":"10.3390","volume":"4","author":[{"ORCID":"https:\/\/orcid.org\/0009-0007-2729-5821","authenticated-orcid":false,"given":"M\u00e1rio C. O.","family":"Spinelli","sequence":"first","affiliation":[{"name":"Department of Mechanical Engineering, Federal University of Rio Grande do Norte, Natal 59078-900, Rio Grande do Norte, Brazil"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6754-4470","authenticated-orcid":false,"given":"Salom\u00e3o S.","family":"Batista","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering, Federal University of Rio Grande do Norte, Natal 59078-900, Rio Grande do Norte, Brazil"},{"name":"Federal Institute of Rio Grande do Norte, Santa Cruz 59200-000, Rio Grande do Norte, Brazil"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4724-9252","authenticated-orcid":false,"given":"Polyane A.","family":"Santos","sequence":"additional","affiliation":[{"name":"Centre for Mechanical Technology and Automation, Department of Mechanical Engineering, University of Aveiro, 3810-193 Aveiro, Portugal"},{"name":"Department of Electrical Engineering, Federal Institute of Bahia, Vitoria da Conquista 45078-900, Bahia, Brazil"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4980-7011","authenticated-orcid":false,"given":"Kenedy Marconi G.","family":"Santos","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, Federal Institute of Bahia, Vitoria da Conquista 45078-900, Bahia, Brazil"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0286-2056","authenticated-orcid":false,"given":"Crescencio R. L.","family":"Neto","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, Federal Institute of Bahia, Vitoria da Conquista 45078-900, Bahia, Brazil"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-8695-1079","authenticated-orcid":false,"given":"Elvio P.","family":"Silva","sequence":"additional","affiliation":[{"name":"Centre for Mechanical Technology and Automation, Department of Mechanical Engineering, University of Aveiro, 3810-193 Aveiro, Portugal"},{"name":"Department of Electrical Engineering, Federal Institute of Bahia, Vitoria da Conquista 45078-900, Bahia, Brazil"}]},{"ORCID":"https:\/\/orcid.org\/0009-0009-0004-1332","authenticated-orcid":false,"given":"Leonardo S.","family":"Caires","sequence":"additional","affiliation":[{"name":"Centre for Mechanical Technology and Automation, Department of Mechanical Engineering, University of Aveiro, 3810-193 Aveiro, Portugal"},{"name":"Department of Electrical Engineering, Federal Institute of Bahia, Vitoria da Conquista 45078-900, Bahia, Brazil"}]},{"ORCID":"https:\/\/orcid.org\/0009-0006-5830-1537","authenticated-orcid":false,"given":"Ronaldo M.","family":"Lima","sequence":"additional","affiliation":[{"name":"Centre for Mechanical Technology and Automation, Department of Mechanical Engineering, University of Aveiro, 3810-193 Aveiro, Portugal"},{"name":"Department of Physics, Federal Institute of Sergipe, Lagarto 49400-000, Sergipe, Brazil"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5758-5578","authenticated-orcid":false,"given":"Am\u00e9lia M.","family":"Santos","sequence":"additional","affiliation":[{"name":"Centre for Mechanical Technology and Automation, Department of Mechanical Engineering, University of Aveiro, 3810-193 Aveiro, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0054-0771","authenticated-orcid":false,"given":"Sergio M. O.","family":"Tavares","sequence":"additional","affiliation":[{"name":"Centre for Mechanical Technology and Automation, Department of Mechanical Engineering, University of Aveiro, 3810-193 Aveiro, Portugal"},{"name":"Intelligent Systems Associate Laboratory, 4800-058 Guimar\u00e3es, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5328-1705","authenticated-orcid":false,"given":"Rui A. S.","family":"Moreira","sequence":"additional","affiliation":[{"name":"Centre for Mechanical Technology and Automation, Department of Mechanical Engineering, University of Aveiro, 3810-193 Aveiro, Portugal"},{"name":"Intelligent Systems Associate Laboratory, 4800-058 Guimar\u00e3es, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1232-0258","authenticated-orcid":false,"given":"D\u00e9cio R. M.","family":"Faria","sequence":"additional","affiliation":[{"name":"Institute of Systems Engineering and Information Technologies, Federal University of Itajuba, Itajuba 37500-903, Minas Gerais, Brazil"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8447-784X","authenticated-orcid":false,"given":"Jose A. D.","family":"Amado","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, Federal Institute of Bahia, Vitoria da Conquista 45078-900, Bahia, Brazil"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3488-5500","authenticated-orcid":false,"given":"Jo\u00e3o E. S.","family":"Marques","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, Federal Institute of Bahia, Vitoria da Conquista 45078-900, Bahia, Brazil"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1234-1729","authenticated-orcid":false,"given":"Luiz G. M.","family":"Souza","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering, Federal University of Rio Grande do Norte, Natal 59078-900, Rio Grande do Norte, Brazil"}]}],"member":"1968","published-online":{"date-parts":[[2026,1,6]]},"reference":[{"key":"ref_1","unstructured":"(2025, September 26). Posso Utilizar Cavaco de Usinagem Para Fabricar Pe\u00e7as? 2013. Available online: https:\/\/www.aquecimentoindustrial.com.br\/posso-utilizar-cavaco-de-usinagem-para-fabricar-pecas\/."},{"key":"ref_2","unstructured":"Ortiz, F. (2025, July 20). Voc\u00ea j\u00e1 Respirou p\u00f3 de Ferro? Conhe\u00e7a o ar Sujo de Piqui\u00e1. 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