Composites

A composite is a material that is a combination of thermoset plastics and various polymeric fibers, that is more than twice as strong and just as lightweight as the two materials. Composite materials are made by incorporating fibers into any thermost medium such as, thermost plastics, metals, or even ceramics.

There are many examples of composites in nature. The reasons why a tree can grow as tall as they do and support the branches they have is because it is a composite of flexible cellulose fibers in a lignin matrix. Seashells and limestone are both made of calcium carbonate. Seashells are much harder because they are composites of crystalline calcium carbonate with embedded polypeptide fibers. Humans have been fabricating composites ever since they began mixing straw with clay. The straw made stronger pots as well as bricks. It also kept the clay from cracking when it dries.

The strongest new composites are the advanced composites. They are fibers that are aligned or interwoven before being set withing the resin. They have extraordinary strength in the direction in the aligned fibers and are weak in the perpendicular directions. Weakness in one direction can be overcome by laminating layers at different angles, as in plywood. Strength in all directions can be achieved by weaving the fibers into a 3-dimensional network. Besides strength, they are also known for their lightness, which makes them ideal for car parts, sporting goods and artificial limbs. Advanced composites are handmade to they tend to be expensive.

Airplane parts are being created by advanced composites because the lightweight composites save fuel. In 1986, the voyager was the first plane made out of advanced composites and it flew around the world without refueling. The aerospace industry is interested in advanced composites that are lightweight and that can withstand extreme pressures and temperatures experienced by spacecrafts. They want to build a vehicle that can transport astronauts and scientists to the moon by 2015 and then to Mars by 2020. The same materials for planes may kne day be used for commercial travel. Hypersonic aircraft traveling faster then the speed of sound would reduce the length of travel from there U.S. to Australia from a long 16 hour trip to only 3 hours. They would fly that high that they would be able to see the curvature of planet Earth.

Back