Surface analysis of accelerated aged epoxy nanocomposites with titanium dioxide and functionalized carbon nanotubes

Abstract This study develops and characterizes epoxy‐based nanocomposites reinforced with titanium dioxide (TiO₂) and carboxyl‐functionalized multi‐walled carbon nanotubes (MWCNT‐COOH) to improve mechanical durability under accelerated aging. Four configurations: neat epoxy (NE), E+0.1C (0.1 phr MWCNT‐COOH), E+2 T (2 phr TiO₂), and E+0.1C + 2 T (binary nanocomposite) were fabricated using magnetic stirring, ultrasonication, and vacuum degassing. Samples underwent continuous ultraviolet (UV) exposure and 4‐h moisture cycles following 8‐h intervals. Mechanical tests, including Vickers hardness (H_V) and micro‐scratch evaluations, were performed before aging and after 132 and 264 h, along with moisture absorption assessments. Microstructural and chemical analyses using energy dispersive X‐ray (EDX) and Fourier transform infrared (FTIR) evaluated nanofiller dispersion and filler–matrix interactions. After 264 h, the binary nanocomposite exhibited a 0.78% weight increase versus 0.89% for NE and maintained approximately 9% higher H_V before aging and at 132 h, with differences becoming insignificant by 264 h. For the scratch length of 5 mm, the coefficient of friction (CoF) after 264 hours of aging stabilized at approximately 0.29 under constant loading and 0.22 under progressive loading for both the binary nanocomposite and NE samples. However, the NE samples exhibited an initial spike in CoF, which was not observed in the binary nanocomposite samples. The morphology study of the scratched samples done using the scanning electron microscope (SEM) supported the numerical results. Overall, it was observed that the binary nanocomposite demonstrated optimum mechanical properties and the lowest moisture absorption after prolonged aging. Highlights TiO₂ and MWCNT‐COOH effects on epoxy surface durability are investigated. Aging of samples is done under UV radiation and moisture for up to 264 h. Vickers hardness and micro‐scratch analysis were carried out in this study. Binary‐modified nanocomposites showed optimal durability after aging. Findings support use in extreme environments for commercial applications.