Structure Kevlar Aramid Fiber example essay topic

STRUCTURE Kevlar Aramid Fiber is a synthetic (man-made) material known as a Polymer. A polymer is a chain that is made up of many similar molecular groups, better known as 'monomers' that are bonded together. 'Monomers' are made up of fourteen Carbon atoms, two Nitrogen atoms, two Oxygen atoms and ten Hydrogen atoms. A single Kevlar polymer chain could possibly have anywhere from one to five million monomers bonded together. A group of polymer chains can be organised together in a fiber. How the polymer chains are put together is important, as it improves the properties of the material.

The flexibility, strength and stiffness of Kevlar fiber, is dependent on the orientation of the polymer chains. Kevlar fiber is an arrangement of molecules, orientated parallel to each other. This orderly, untangled arrangement of molecules is described as a "Crystalline Structure". A manufacturing process known as 'Spinning' is needed to achieve this Crystallinity structure. Spinning is a process that involves forcing the liquefied polymer solution through a 'die' (small holes). The Crystallinity of Kevlar Polymer strands, contributes to the unique strength and stiffness of the material.

Kevlar is very similar to other common synthetic polymers, including Nylon, Teflon and Lycra. In all Plated to strength. Aromatic refers to the Carbon atoms attached in a ring, and Amides refers to a group of Carbon, Nitrogen and Hydrogen atoms. Kevlar fiber is therefore a "Poly aromatic amide", as it has a high breaking strength. Polymer chains are long, individual chains, although they behave as if they are attached to each other. The individual chains are actually held together by 'Electrostatic Forces' between molecules, also known as 'Hydrogen Bonds'.

Scientists discovered this, by using a special type of X-ray microscopy called 'XANES'. This was able to reveal the orientation of molecules in materials. It has also been discovered that the components of Kevlar fiber, have a radial orientation that is in a crystal. The crystal-like regularity is the largest contributing factor in the strength of Kevlar fiber. PROPERTIES It is five times stronger, yet the same weight as steel. Kevlar Aramid fiber is an improved material, which is an extremely lightweight, man-made organic fiber.

Kevlar fiber has a combination of properties, which have made Kevlar a very useful material. These include, high strength, low weight, high chemical resistance and high cut resistance. This material does not corrode or rust and is also unaffected when placed in or under water. This material is flame resistant and it will not melt, soften or flow when exposed to high temperatures.

It is stable at high temperatures, as well as at normal temperature and storage conditions. There is fortunately a low shrinkage rate at high temperatures and only at an extremely high temperature of 427^0 C, will Kevlar fiber actually begin to burn. Therefore, Kevlar will not burn at average temperatures, and requires a large amount of heat for a significant temperature change. Kevlar fiber has also proven to be a far better thermal insulating material than most conventional fibers.

Kevlar has a good balance of key properties, which is suitable for high performance applications. With a good elasticity and dimensional stability, it is stronger than most metals, yet comparatively lightweight. Its thermal performance is also greater than most metals, including stable properties at a temperature range from -250^0 C to 200^0 C. This material also has the ability to self-extinguish, has no melting point and can resist powerful physical shocks. Although Kevlar fiber is significantly safer than most fibers, when a Kevlar fabric is laser cut, a small amount of toxic gases may be generated, yet has been proven to give off the lowest total amount of toxic gases. The pulp or dust of Kevlar fiber doesn't present any explosion hazard, and in any form, Kevlar fiber is reasonably safe. Although Kevlar has poor abrasion (scratch) resistance, scientists have found that finish oil will protect the material.

This is why most Kevlar products are covered with a small amount of oil to protect them from abrasion. Most organic solvents (oil) have little effect on the material, and most salt solutions (sodium chloride) have no effect on Kevlar fiber. However, strong acids and bases (hydrochloric acid and sodium hydroxide) at high concentrations or elevated temperatures are able to attack Kevlar fiber. Kevlar fiber has a highly ordered crystalline structure and this contributes to its unique features, compared to other conventional fibers. web 'Kevlar Aramid Fiber' web 'Kevlar Fiber'.