3. Reinforcement of rigid and semi-rigid foams

The reinforcement of rigid foams has been developed relatively recently for applications where the criteria of choice are lightness, sound and thermal insulation, and rigidity. Glass fiber reinforcement, which is currently the most widely used, improves the poor mechanical properties of foams, which previously limited their use in composite materials to the cores of sandwich panels. The main improvements concern Young's modulus, flexural strength, impact resistance, temperature resistance and dimensional stability.