Research Advancements in the Mechanical Performance and Functional Properties of Nanocomposites Reinforced with Surface-Modified Carbon Nanotubes: A Review

This review summarizes the recent advancements in the mechanical properties of nanocomposites reinforced with surface-modified carbon nanotubes (CNTs). A range of matrices, namely, polymers, metals, and cement, is investigated, which have demonstrated increasing importance in a broad range of industrial sectors, such as 3D printing, automotive, construction, and coatings. The strengthening mechanisms that CNTs impart in composites are reviewed, and synergistic effects with their surface groups or co-additives are analyzed, including wettability, mechanical interlocking, and chemical bonding. Different mechanical and functional properties of the CNT-reinforced nanocomposites are analyzed, such as tensile strength, flexural strength, impact resistance, thermal conductivity, and electrical conductivity. The improvements in these properties for a variety of CNT-based composites are presented, and details on how these improvements were attained are discussed. The review concludes that surface modification of CNTs has proven to be of high importance, enhancing compatibility with various matrices and facilitating improvements in the nanocomposite properties. Suggestions for viable CNT-based composites for use in the studied applications are also provided.