Matrix

Functions of a matrix are as follows:

1. It has to work as a binder.
2. It is to keep the position and orientation of the reinforcement.
3. It is to balance the loads between the reinforcement.
4. It has to protect the reinforcement from degradation.
5. It has to retain the shape and form of the finished structure.

Thermosetting resins are the most common type of matrix. These resins have the property of reacting chemically under certain time and temperature conditions. Epoxy resins are the most widely used thermosetting resins. Polyester, vinyl ester, phenolic, bismaleimide, epoxy novolac, polymide, etc., are the other matrixes.

Composites may be natural composite or man-made. For example, wood, bones, teeth, etc., are natural composites. Wood comprises of cellulose fibres with good strength and stiffness in a resinous matrix of polysaccharide.

Man-made composites are many and they are as follows:

1. Bricks made out of mud and straw.
2. Plywood is a composite laminate.
3. Concrete is an excellent example of a ceramic composite.
4. Reinforced plastics.
5. Wire reinforced tiles.
6. Fibre-reinforced glass.

Keeping in view the basic concepts of reinforcement and matrix, any combination of materials can be tried to suit a specific need.