PSI - Issue 82

ScienceDirect Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2026) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2026) 000–000 Available online at www.sciencedirect.com

www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia

Procedia Structural Integrity 82 (2026) 274–280

© 2026 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of ICSID organizers Abstract Polyamide-based composites are increasingly used in engineering applications exposed to outdoor environments, where ultraviolet (UV) radiation represents a major factor affecting their long-term performance. This study investigates the influence of UV exposure on the degradation mechanisms and property evolution of polyamide (PA) and polyamideimide (PAI) composites reinforced with short glass fibers at concentrations of 10, 20, and 30 wt%. The effects of UV irradiation on the materials were evaluated through mechanical, microstructural, and rheological analyses. The results revealed a reduction in Shore D hardness and impact toughness, particularly in composites with lower glass fiber content. Microscopic observations confirmed surface cracking, matrix embrittlement, and partial fiber–matrix debonding after 500 hours of UV exposure. Rheological measurements indicated a decrease in complex dynamic viscosity and a shift in the crossover point, corresponding to a reduction in molecular weight and an increase in polydispersity of the surface layers up to 250 µm deep. Higher glass fiber content was found to mitigate UV penetration and delay surface degradation. The findings emphasize the importance of fiber reinforcement in improving the UV stability of polyamide-based composites and contribute to the development of durable materials for outdoor structural and automotive applications. © 2026 The Authors. Copy from the contract: Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of ICSID organizers Keywords: polyamide composites; polyamideimide; UV degradation; glass fiber reinforcement; rheological behavior; mechanical properties 1. Introduction Polymer-based composites have become an essential class of engineering materials due to their favorable combination of low density, high specific strength, and design flexibility. Among them, polyamides (PA) and 8th International Conference on Structural Integrity and Durability (ICSID2025) UV-Induced Degradation Behavior of Polyamide-Based Composites Reinforced with Short Glass Fibers Lenka Markovičová a, *, Milan Uhríčik a , Juraj Belan a , Viera Zatkalíková a , Silvia Hudecová a , Lukáš Šikyňa a a University of Žilina, Faculty of Mechanical Engineering, Univerzitná 8215/1, 010 26 Žilina, Slovakia Abstract Polyamide-based composites are increasingly used in engineering applications exposed to outdoor environments, where ultraviolet (UV) radiation represents a major factor affecting their long-term performance. This study investigates the influence of UV exposure on the degradation mechanisms and property evolution of polyamide (PA) and polyamideimide (PAI) composites reinforced with short glass fibers at concentrations of 10, 20, and 30 wt%. The effects of UV irradiation on the materials were evaluated through mechanical, microstructural, and rheological analyses. The results revealed a reduction in Shore D hardness and impact toughness, particularly in composites with lower glass fiber content. Microscopic observations confirmed surface cracking, matrix embrittlement, and partial fiber–matrix debonding after 500 hours of UV exposure. Rheological measurements indicated a decrease in complex dynamic viscosity and a shift in the crossover point, corresponding to a reduction in molecular weight and an increase in polydispersity of the surface layers up to 250 µm deep. Higher glass fiber content was found to mitigate UV penetration and delay surface degradation. The findings emphasize the importance of fiber reinforcement in improving the UV stability of polyamide-based composites and contribute to the development of durable materials for outdoor structural and automotive applications. © 2026 The Authors. Copy from the contract: Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of ICSID organizers Keywords: polyamide composites; polyamideimide; UV degradation; glass fiber reinforcement; rheological behavior; mechanical properties 1. Introduction Polymer-based composites have become an essential class of engineering materials due to their favorable combination of low density, high specific strength, and design flexibility. Among them, polyamides (PA) and 8th International Conference on Structural Integrity and Durability (ICSID2025) UV-Induced Degradation Behavior of Polyamide-Based Composites Reinforced with Short Glass Fibers Lenka Markovičová a, *, Milan Uhríčik a , Juraj Belan a , Viera Zatkalíková a , Silvia Hudecová a , Lukáš Šikyňa a a University of Žilina, Faculty of Mechanical Engineering, Univerzitná 8215/1, 010 26 Žilina, Slovakia

* Corresponding author. Tel.: +421-41-513-2610. E-mail address: lenka.markovicova@fstroj.uniza.sk * Corresponding author. Tel.: +421-41-513-2610. E-mail address: lenka.markovicova@fstroj.uniza.sk

2452-3216 © 2026 The Authors. Copy from the contract: Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of ICSID organizers 2452-3216 © 2026 The Authors. Copy from the contract: Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of ICSID organizers

2452-3216 © 2026 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of ICSID organizers 10.1016/j.prostr.2026.04.042