sharing our knowledge.
Photographic gallery.  Thousands of particles under the microscope.
Polyester Fiber, KODEL

Polyester Fiber, KODEL

This is a sample polyester fiber from the sample-set provided by Textile Fabric Consultants, Inc. Kodel is a trademarked product of the Eastman Chemical Company. The high birefringence and small diameter of the fiber results in the high order interference colors seen here. Larger diameters would appear in high order white.

Transmitted 20 Degrees Off Crossed Linear Polarized Light


Polyester fiber is derived from terephthalic acid. It is formed into a fiber by extruding the heated polymer through a spinneret. This results in the fiber taking the cross-section of the spinneret. Polyester fiber can be round or any other desirable extruded shape.

Significance in the Environment:

This is a common clothing fiber.

Characteristic Features:

Rayon fiber has a refractive index along its length of about 1.71 to 1.73 and perpendicular to its length of about 1.53 to 1.54. It has a birefringence of about 0.18 and a positive sign of elongation. It tends to exhibit a smooth, regular surface along its length depending on its cross-section of the fiber. Extreme shapes, such as heptalobate types, can result in an irregular appearance along the length as the fiber twists or bends.

Associated Particles:


DuPont Company Techinical Bulletin X-156: IDENTIFICATION OF FIBERS IN TEXTILE MATERIALS, December 1961.