Definition of Composite: Composite materials are formed by the combination of two or more solid materials that do not mix with each other. Many natural substances exhibit composite properties. One of the most significant characteristics of composite materials is that they possess superior qualities compared to the individual materials that make them up.
Characteristics of Composites: Composites are favored due to their low density compared to metals, ease of shaping, high resistance to corrosion, and good surface quality. Particularly, polymer composites offer advantages in many fields due to their dimensional and thermal stability, high strength, rigidity, and exceptional resistance to wear. Furthermore, composite materials can compete with metals in terms of durability and rigidity while being exceptionally lightweight. Composites typically consist of three fundamental elements: Matrix, Reinforcement, and Additives.
Matrix: The continuous phase of the matrix is made from thermosetting or thermoplastic polymer materials. In the thermoset group, polyester is predominantly used, along with epoxy resin, phenolic resin, and vinyl ester. The thermoplastic group generally includes polypropylene and polyamide, but can also feature polybutylene terephthalate, polyether ether ketone, and polyethersulfone.
Reinforcement: Reinforcements are materials that enhance the matrix and typically constitute about 60% of the volume. Materials such as aramid, carbon, graphite, boron, silicon carbide, alumina, glass, and polyethylene are commonly used as reinforcements.
Additives: Additives are incorporated to enhance desired properties in composites. They are utilized in various industries such as construction, building, defense, aerospace, and consumer goods when corrosion resistance is necessary. In marine, land transport, and electrical-electronic fields, they can be applied as per specific needs. The use of additives has significantly increased, especially in the automotive sector.
Growing Importance of Composites: Due to their unique properties, composite materials have gained significant importance over the years compared to metal materials. Their low specific weight provides a considerable advantage for use in lightweight structures. Additionally, fiber-reinforced composites are preferred for their corrosion resistance and capabilities in thermal, sound, and electrical insulation. In landscape sectors like infrastructure and environmental planning, the non-recyclability of composites also serves as a deterrent against theft.