As an example of composites with a tailored interface to control mechanical properties, a discussion is provided of glass fiber reinforced plastics from 3B Composites. These composites are primarily used in the areas of wind energy, thermoplastics and specialty markets such as military and paramilitary uses. To satisfy the requirements of each of these markets, the glass reinforcement material is tailor-made to meet both the process and end-use needs. This is achieved through the appropriate modification of the glass sizing to meet a particular application. This modification allows for the compatibility and chemical interaction between the polymer matrix material and the reinforcing glass fiber.