Buckypaper functionalized shape memory polymer composites for improved thermo-mechanical and shape memory performance

There has been an increased interest in shape memory polymers (SMPs), which offer unique characteristics, such as dual shape recovery and large deformations, for aerospace and other applications. This work investigates a carbon nanotube (CNT) based SMP composite with enhanced thermo-mechanical and shape memory performance. The composite was fabricated by integrating SMP-impregnated buckypaper (BP) interleaves into a woven glass fiber composite. The BP layers served as conductive backbones, enabling joule heating at low voltages. Thermomechanical tests under tensile and shear loads, along with microstructural analysis, were conducted to understand the mechanisms behind the improved performance. The influence of BP layers on failure behavior was investigated and the results show an increase in strain to failure. Further investigation using scanning electron microscopy (SEM) was conducted to determine the microstructural features that impede crack propagation and improve interfacial load transfer. Dynamic mechanical analysis (DMA) assessed the BP layers' impact on viscoelastic behavior. Shape memory performance was evaluated through constrained and free recovery experiments. Parametric studies were conducted to investigate the impact of BP placement, number, and fiber orientation on shape memory behavior. The results demonstrate the potential of BP-functionalized SMP composites for advanced structural applications, offering improved multifunctional capabilities and electro-active actuation.