{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,10]],"date-time":"2026-07-10T16:08:25Z","timestamp":1783699705800,"version":"3.55.0"},"reference-count":34,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2025,2,22]],"date-time":"2025-02-22T00:00:00Z","timestamp":1740182400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Polymers"],"abstract":"<jats:p>This study investigated the effects of multiple laser sintering (LS) cycles on a polyamide 12 powder mixture of 70% recycled material and 30% virgin polymer. This research aimed to understand how repeated LS processing influences this specific powder mixture\u2019s thermal and structural properties, which is crucial for optimising its performance in additive manufacturing applications. A thermal analysis revealed significant changes in the thermal behaviour of the powder over successive build cycles. Specifically, there was an observed increase in both the melting temperature and the crystallinity of the powder, alongside a notable decrease in the crystallisation temperature. These alterations suggest that the repeated LS cycles affect the thermal profiles and potentially enhance the material\u2019s stability and usability in additive manufacturing processes. Additionally, a particle size distribution analysis indicated statistically significant differences between the initial and post-sintering states of the powder. These differences are significant as they can influence factors such as flowability and packing density, which are critical for the efficiency of additive manufacturing applications. Microscopic observations further revealed a strong correlation between the crystal morphologies and particle shapes, indicating that the structural changes occurring during processing are inter-related. The relationship underscores the importance of understanding microstructural evolution and the mechanical properties of the final printed products. These findings provide crucial insights into the microstructural evolution and thermal behaviour of recycled PA12 powder during multiple LS processing cycles. This study aids in developing practical strategies for sustainable and efficient powder recycling within the realm of additive manufacturing. By examining the intricate dynamics at play, the research opens avenues for enhancing the performance and environmental sustainability of 3D printing technologies, making them more accessible for various industrial applications.<\/jats:p>","DOI":"10.3390\/polym17050577","type":"journal-article","created":{"date-parts":[[2025,2,24]],"date-time":"2025-02-24T10:52:47Z","timestamp":1740394367000},"page":"577","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["The Influence of Mixed Powder Ageing on the Structural, Chemical, and Crystalline Morphological Properties of the PA12 Used to Manufacture Laser Sintering"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2518-1093","authenticated-orcid":false,"given":"Alejandro","family":"Garc\u00eda Rodr\u00edguez","sequence":"first","affiliation":[{"name":"Facultad de Ingenier\u00eda Mec\u00e1nica, Universidad Santo T\u00f3mas, Carrera 9 No 51-11, Bogot\u00e1 110231, Colombia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Edgar","family":"Espejo Mora","sequence":"additional","affiliation":[{"name":"Mechanical and Mechatronics Engineering Department, Universidad Nacional de Colombia, Carrera 45 No 26-85, Building 407, Bogot\u00e1 111321, Colombia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4436-9443","authenticated-orcid":false,"given":"Marco Antonio","family":"Velasco Pe\u00f1a","sequence":"additional","affiliation":[{"name":"Technological Faculty, Universidad Distrital Francisco Jos\u00e9 de Caldas, Calle 13 No 31-75, Bogot\u00e1 110231, Colombia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6102-9841","authenticated-orcid":false,"given":"Carlos Alberto","family":"Narv\u00e1ez Tovar","sequence":"additional","affiliation":[{"name":"Mechanical and Mechatronics Engineering Department, Universidad Nacional de Colombia, Carrera 45 No 26-85, Building 407, Bogot\u00e1 111321, Colombia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,2,22]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"105304","DOI":"10.1088\/2053-1591\/acf6f7","article-title":"Mechanical properties of polyamide 12 manufactured by means of SLS: Influence of wall thickness and build direction","volume":"10","author":"Mora","year":"2023","journal-title":"Mater. 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