Introduction - Polymers ( Cliquer ici pour la version franšaise )

Kevlar belongs to a large group of molecules named polymers. Polymers are molecules made up of long chains of smaller molecules, named monomers. The majority of polymers contain only one type of monomer, but they can also contain combinations of many different types of monomers.

The term "plastic" refers to polymers that can be heated and molded into different shapes. Synthetic processes involving chemical reactions create all polymers. Several plastics can be woven to form fibres such as rayon, nylon, polyester and Kevlar. Modern society relies heavily on the use of plastics; they are extremely relevant in daily applications. Plastics can be seen in a wide variety of applications in business sectors and everywhere a person can go. For this reason, companies that invent new polymers guard their products cautiously by swiftly applying for patents. Kevlar is no exception; Stephanie Kwolek of DuPont patented it in 1966.

Polymers are formed by the chemical reactions of addition or condensation. They are given a "poly" prefix in front of the common name of the monomer used. Monomers with double connections form polymers by a reaction of addition. The connections are broken and many monomers are linked together. Polymers are formed by a condensation reaction when ester or amide groups are present in the products. The secondary product of this type of reaction is water. Each monomer in the reaction has two functional groups to facilitate it. The products with amide bonds are called nylons or polyamides. The products with ester bonds are called polyesters.