Polymer nanocomposites filled with carbon nanotubes CNTs exhibit enhanced mechanical and thermal properties compared to traditional polymer composites filled with micro fillers. This is due to the unique characteristics of carbon nanotubes, which include high aspect ratio, exceptional mechanical strength, and excellent thermal and electrical conductivity.Mechanical properties:1. Improved tensile strength: The incorporation of CNTs into polymer matrices leads to a significant increase in tensile strength. This is because the high aspect ratio of CNTs allows for effective stress transfer from the polymer matrix to the nanotubes, resulting in better load-bearing capacity.2. Enhanced stiffness: The presence of CNTs in the polymer matrix increases the stiffness of the composite material. This is due to the strong interfacial interactions between the CNTs and the polymer matrix, which restrict the mobility of polymer chains and increase the overall rigidity of the composite.3. Increased toughness: Polymer nanocomposites with CNTs exhibit higher toughness compared to traditional composites with micro fillers. The CNTs can effectively bridge cracks and prevent crack propagation, leading to improved resistance to fracture.4. Improved fatigue resistance: The addition of CNTs to polymer matrices can also enhance the fatigue resistance of the composite material. This is attributed to the ability of CNTs to absorb and dissipate energy during cyclic loading, thereby delaying the onset of fatigue failure.Thermal properties:1. Enhanced thermal conductivity: CNTs have high thermal conductivity, and their incorporation into polymer matrices can significantly improve the thermal conductivity of the composite material. This is due to the formation of a percolating network of CNTs within the polymer matrix, which facilitates efficient heat transfer.2. Improved thermal stability: Polymer nanocomposites with CNTs exhibit better thermal stability compared to traditional composites with micro fillers. The presence of CNTs can delay the onset of thermal degradation and reduce the rate of thermal decomposition of the polymer matrix.3. Reduced coefficient of thermal expansion CTE : The addition of CNTs to polymer matrices can lead to a reduction in the coefficient of thermal expansion of the composite material. This is due to the strong interfacial interactions between the CNTs and the polymer matrix, which restrict the mobility of polymer chains and reduce the overall expansion of the composite upon heating.In summary, polymer nanocomposites filled with carbon nanotubes exhibit superior mechanical and thermal properties compared to traditional polymer composites filled with micro fillers. These enhanced properties make CNT-filled polymer nanocomposites attractive for various applications, such as aerospace, automotive, electronics, and energy storage.