**1. Introduction**

Composites are materials containing at least two constituents, each one with different chemical composition. Their combination provides a new material with better functional properties than each of the components separately [1].

The main component in the composite is the matrix, which can be a metal, ceramic or polymer, while the other part is a reinforcement which can be in particulate, laminate, short fiber or long fiber form [2]. Composite materials are widely used in construction, aerospace, aircraft, medicine, electrical and automotive industries [2–5]. Here, a focus is made on fiber reinforced composites made from a polymer matrix reinforced with fibers having a natural origin [6].

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
