Particle-toughened fiber-reinforced polymer composites

Particle toughened, fiber-reinforced composites include a fiber region and an interlayer region between the fibers. The fiber region includes a plurality of fibers at least partially within a first polymer composition including a first base polymer formulation and a first plurality of toughening particles. The interlayer region includes a second polymer composition including a second base polymer formulation and at least one of the first plurality of toughening particles and a second plurality of toughening particles. Examples of first and second pluralities of toughening particles, respectively, may include core shell rubbers and polyimides. Increasing concentration of the first plurality of toughening particles may improve the composite toughness while preserving thermal properties of the composite, such as weight loss after extended duration exposure to elevated temperature. It is further discovered that the relative placement of the toughening particles influences composite mechanical properties, such as compression after impact (CAI) strength.