Low‐Velocity Impact Response of Halloysite Nanotube Reinforced Glass/Epoxy Multi‐Scale Composite Part 2: Effect of Acidic Aging Environment

ABSTRACT Laminated fiber‐reinforced composites are widely used in structural applications, yet their performance deteriorates under harsh environmental and dynamic loading conditions. This study examines the low‐velocity impact behavior of glass fiber/epoxy composites aged in acidic conditions, with and without halloysite nanotube (HNT) reinforcement. After 42 days of immersion in an acidic medium, water absorption reached 9% in unmodified GFRP, whereas it remained limited to 4% in HNT‐reinforced composites (Ms‐GFRP). ICP–OES analysis further showed that Ms‐GFRP released substantially fewer dissolved elements into the solution, confirming its enhanced chemical stability. Low‐velocity impact tests demonstrated that HNT addition significantly improved impact resistance under all aging durations. After 14 days of acidic exposure, Ms‐GFRP exhibited 34%–40% higher peak load capacity than GFRP at impact velocities of 2, 2.5, and 3 m/s, with similar trends observed after 28 and 42 days. Deflection values after 42 days increased by 24%–49% in Ms‐GFRP, compared to 34%–49% in GFRP, indicating reduced structural degradation. Likewise, the reduction in energy absorption remained slightly lower in Ms‐GFRP (up to 43%) than in GFRP (up to 45%). The results demonstrate that HNT reinforcement enhances both the mechanical integrity and environmental durability of glass/epoxy composites by mitigating moisture diffusion and acid‐induced degradation. These findings highlight Ms‐GFRP as a promising material for applications requiring improved resistance to corrosive environments and impact loading.