A KEVLAR® fiber is a collection of molecules that are positioned parallel. This arrangement of  the molecules is called a crystalline structure. Crystallinity can only be created through a manufacturing process called spinning. Spinning involves extracting the molten polymer solution through small holes which creates little strands. The crystallinity of the KEVLAR® fibers is what contributes significantly to KEVLAR®'s unique strength and rigidity. The elements in the KEVLAR® compound are bonded by covalent bonds which are very strong chemical bonds between the atoms, this is another reason that KEVLAR® is so strong.  There are many double bonds within the compound that contribute to the strength of the compound and structural ruggedness .

This is a picture of Kevlar's structure