LAMINATED NANOCOMPOSITES AND NANO-REINFORCED ADHESIVELY BONDED JOINTS WITH IMPROVED MECHANICAL PERFORMANCE AND ADHESION

Composite laminates and bonded joint assemblies have several advantages, and they are widely used in structural applications, because of their lightweight, high strength and stiffness, corrosion resistance, tailorable properties, damage tolerance, reduced maintenance, design flexibility, and tunable thermal and electrical properties. Despite having these superior properties and advantages over traditional materials, composite laminates and joints do have several disadvantages including poor interlaminar properties, difficulty to adhesively bond and repair, sensitivity to UV radiation and moisture, and limited impact resistance and through-the-thickness properties. One of the most promising solutions that can address some of the shortcomings is to incorporate nanomaterials, e.g., carbon nanotubes (CNTs), as a nanoscale reinforcement between the traditional microfiber reinforcements and within the resin system to improve the interlaminar and through-the-thickness properties of the composite laminates and bonded joints assemblies. Our prior studies demonstrated that helical CNTs (HCNTs) perform better than the straight CNTs (SCNTs), due to their unique helical geometries that can provide a nanoscale interlocking mechanisms between the reinforcements and within the solidified resin. In this study, composite and HCNTs reinforced nanocomposite panels with varying weight percentages of HCNTs inclusion (i.e., 0wt%, 0.025wt%, and 0.05wt%) were prepared, cut, and prepared for mechanical testing and analysis, as per ASTM standards (i.e., ASTM D790-17, ASTM D2344/2344M-16, ASTM D3039/D3039M-17, and ASTM D5868-01). The test results for flexural strength, short-beam strength, tensile strength, and single-lap shear strength for the nanocomposite samples with HCNTs reinforcements were compared to those without nano-reinforcements and promising results were obtained.