Composite Materials Composites are combinations of two more separate materials on a microscopic level, in a controlled manner to give desired properties.For over 5000 years, composites have been used in building materials, plastics, insulation, communications equipment, automobiles, and protective gear.Wood is a composite – it is made from long cellulose fibres (a polymer) held together by a much weaker substance called lignin. Cellulose is also found in cotton, but without the lignin to bind it together it is much weaker. The biggest advantage of modern composite materials is that they are light as well as strong. By choosing an appropriate combination of matrix and reinforcement material, a new material can be made that exactly meets the requirements of a particular application.The promise of a “no-compromises” material that accomplishes exactly what you want sounds like a fantasy. Yet, composite materials manage to do just that. Composite materials achieve the majority of their beneficial properties from a strong bond between the strong, stiff reinforcement. Natural composites exist in both animals and plants.