What is a composite?
A material that is made from two or more materials which have significantly different physical or chemical properties; when combined they create a single material which is often lighter and stronger that the original materials on their own
Why are composites used?
Because they can be engineered to meet the exact requirements of a specific application
Examples of early composites (2)
- Combining mud (wet soil or clay) with plant material such as straw to make bricks
- Concrete, comprised of small stones and gravel with cement and sand
Three main composite groups (modern composites)
- Carbon-fibre Reinforced Polymers (CFRP)
- Glass-fibre Reinforced Polymers (GRP)
- Aramid products (Kevlar®)
Glass-fibre Reinforced Polymers (GRP)
A relatively composite material, also known as fibreglass which is made from strands of glass which form a flexible matrix or fabric
Benefits of GRP
- Strong compared to its weight
- Corrosion resistant
- Water resistant
- Variation during manufacture in the thickness of layers can produce different weights and strengths
- Suited for batch productions
Kevlar®
One of a family of materials developed froma synthetic fibre created by chemist Stephanie Kwolek in 1965; formed by combining paraphenylenediamine and terephtaloyl chloride to result in a super stiff, heat resistant polymer that is nine times stronger than nylon
Benefits of Kevlar®
- Lighter
- Stronger
- Flexible
- High performance
- Safer
- Natural toughness allows fabrics and threads to stand up to repeated abuse
- Helps minimise vibration transfer
- Can sustain deformation without breaking
Carbon-fibre Reinforced Polymers (CFRP)
One of the most expensive composite materials but boasts the best strength to weight ratio of any construction material; it is made from high tensile strength carbon fibres which are woven together and then encased in a polymer resin
Benefits of CFRP
- Resistant to stretching
- Rigid
- Light in weight yet strong
- High tolerance to heat
Examples of where GRP is used (5)
Manufacture of:
- Car bodies
- Water tanks
- Swimming pool slides
- Canoes
- Boat hulls
Examples of where Kevlar® is used (2)
Manufacture of:
- Garments, mostly known for bullet-proof vests
- Personal Protective Equipment (PPE), used to protect people working in hazardous jobs
Examples of where CFRP is used
Manufacture of products in the:
- Marine industry
- Automotive industry (e.g. Formula 1 car bodies)
- Defence industry
- Sports and leisure industries (e.g. sporting prosthetic limbs)
