Kevlar Fiber

This shows the typical yellow color of kevlar. The high birefringe of Kevlar results in a high order white retardation color so the natural color of the fiber dominates. Small staple fibers can be seen roughly paralleling the horizontal fiber in this image. These small staple fibers are often associated with Kevlar fibers. One of the fibers in this image shows the node-like pattern seen in some Kevlar fibers.

Transmitted Crossed Circular Polarized Light

Definition/Function:

Kevlar is one of the Aramid fibers. It is a para-aramid and is known for its remarkable strength and is used in personnel body armor.

Significance in the Environment:

Characteristic Features:

Kevlar is yellow and can have the highest birefringence, 0.685, and parallel refractive index, 2.322, of any of the synthetic fibers. Typical values for the refractive indices of Kevlar (29 and 49) are 1.646 perpendicular and 2.05 parallel, which gives a birefringence of about 0.4, still the highest by far of any of the synthetic fibers. The different types of Kevlar can sometimes be differentiated by the banding that occurs along the length of the fiber.

Associated Particles:

References:

Gorski, Azriel and Walter C. McCrone, "Birefringence of fibers", THE MICROSCOPE, vol. 46, no. 1, pp. 3-16

http://en.wikipedia.org/wiki/Kevlar