Elevated Temperature Bending and Creep Performance of 3‐D Reinforced GFRP Composites With Functionalized CNTs Aligned Along the Through‐Thickness Direction

ABSTRACT This study presents a comprehensive evaluation of the elevated temperature bending and creep behavior of glass/epoxy (GE) composites with carboxyl‐functionalized carbon nanotubes (FCNTs), with a specific focus to examine the effects of through‐thickness CNT alignment. Two variants of matrix modified GE composites—randomly dispersed FCNT (RFCNT‐GE) and electrically aligned FCNT (AFCNT‐GE) along the through‐thickness direction were fabricated. Flexural test results at 40°C revealed a 19% and 39% increase in strength of RFCNT‐GE and AFCNT‐GE over neat GE, respectively. A substantial improvement in flexural properties was noticed for AFCNT‐GE over RFCNT‐GE at all the testing temperatures (40°C, 70°C, 85°C, and 100°C), and the results are supported by SEM analysis. Dynamic mechanical analysis confirmed enhanced storage modulus for both RFCNT‐GE and AFCNT‐GE over neat GE, with a similar glass transition temperature. Creep studies conducted under varying thermal and loading conditions were fitted with Burgers model to extract strain rates and viscoelastic parameters. AFCNT‐GE consistently exhibited lower strain rates and delayed onset of tertiary creep over RFCNT‐GE, for all the temperatures and loads, highlighting the critical role of FCNT alignment. These findings underscore the potential of z ‐axis aligned FCNTs in FRP Composites, while also identifying limitations for long‐term high‐temperature structural applications.