Composites are heterogeneous in nature, created by the assembly of two or more components with fillers or reinforcing fibres and a compactable matrix. The matrix may be metallic, ceramic or polymeric in origin. It gives the composites their shape, surface appearance, environmental tolerance and overall durability, while the fibrous reinforcement carries most of the structural load thus giving macroscopic stiffness and strength. A composite material can provide superior and unique mechanical and physical properties because it combines the most desirable properties of its constituents while suppressing their least desirable properties.
Fibreglass reinforced plastic (FRP), commonly known as fibreglass, is a thermoset plastic resin that is reinforced with glass fibres. A plastic resin comes in two different classes: thermosets and thermoplastics. The plastic resin system determines chemical, electrical, and thermal properties. Fibre provides strength, dimensional stability, and heat resistance. Additive provide colour and determine surface finish, and affect many other properties like weathering and flame retardancy. Processing of FRP composites involves complex chemical action. Final properties are determined by many factors, including the type, amount and composition of the resin systems and reinforcements. In addition, the use of an additive can greatly affect the FRP composite properties.