What is a composite?

“Composite” is a general term meaning an assembly of various and or dissimilar materials used in conjunction with each other to enable them to do a job or task that the individual materials cannot do by themselves. Reinforced concrete is a composite. Wood is a composite.

“Advanced Composites” normally refers to that group of composite materials usually associated with military of aerospace structures and using more advanced materials and the associated technology.

Composites normally consist of the following, but not limited to these:

  • Resin Matrix. Eg. Epoxy; vinyl-ester; polyester; phenolic and polycyanate resin systems.
  • Fibrous Reinforcement. Eg. Fibreglass; Carbon fibre; Aramid fibre; Spectra fibre; Graphite fibre; Ceramic fibre; Metal fibre; Polyethylene; and combinations of these.
  • Fillers. Eg. Hollow glass microballoons; fibrous fillers; fire-retardant fillers; pigments; thickening agents; calcium carbonate; etc.
  • Core Materials. Eg. Honeycombs; balsa wood; foams; mats; syntactic foams; etc.

The term “reinforced” normally means that some or most of the mechanical properties of a normally homogeneous material are enhanced by means of certain fibres or similar material. To be able to reinforce the other material, the reinforcing fibres should have the following properties:

  • A much higher modulus of elasticity than the plastic material to be reinforced.
  • A higher tensile (yield) strength.
  • Be in a suitable form to be combined with the plastic material.
  • Render the best possible adhesion with the matrix system.
  • Be resistant to the plastic and or other chemical constituents present in the compound.