High Performance Carbon Fiber Reinforced Composites

Numerous recent studies have succeeded in significantly increasing interlaminar fracture toughness under different loading directions (Mode I and II), maintaining the important thermo-mechanical properties of the composite materials without adversely shifting the application limits.

Carbon fiber reinforced composites (CFRP) based on thermosetting polymers show a beneficial combination of high strength and stiffness. These properties make them most favourable for a variety of high performance applications in the aircraft (e. g. weight-bearing wing box) or automotive (e. g. alloy rim) sector. However, the thermoset matrix is brittle due to its high molecular network density that makes it susceptible to damages from high load defects. Critical loads promote crack formation, lead to crack growth and, in the worst case, to component failure.

This intrinsic project researches ways and mechanisms to significantly increase the matrices’ resistance to cracking and crack growth. Nanoparticles with a spherical core-shell structure and block copolymers are embedded into the matrix. Coreshell particles have a defined structure with a ductile core and a rigid shell. Nanoparticles self-assemble from the block copolymers only during the manufacturing process. Due to their size and shape in the nano- and micro-dimension as well as due to the good distribution and adhesion to the polymer matrix, the nanoparticles activate micromechanical toughening mechanisms such as plastic deformation of the soft particle core. As a result, they advantageously counteract crack propagation. Using nanocomposite matrices in carbon fiber reinforced composites also significantly increases the damage tolerance.