The matrix in a fiber-reinforced composite serves to:
- keep the fibers in place,
- transfer stresses evenly over the fibers,
- provide a barrier under adverse conditions such as chemicals and moisture, and
- protect the surface of the fibers from mechanical degradation, for example, as a result of abrasion.
The matrix you select has a major impact on the compressive, interlaminar shear, and in-plane shear properties of the composite material.