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Chromspun Acetate Fiber Under the Microscope

Blue Acetate Fiber, Chromspun

This is a sample acetate fiber from the sample-set provided by Textile Fabric Consultants, Inc. Chromspun is a trademarked product of the Eastman Chemical Company. The blue color is the result of a dye used in the fiber. The low birefringence and small diameter of the fiber would result in a pale bluish gray interference color if the dye were not present.

Transmitted Crossed Linear Polarized Light


Acetate fiber is a cellulose derivative. Wood cellulose or cellulose from cotton linters is often used as the starting material. It is formed by drawing the cellulose solution through a spinneret into an acid bath where it solidifies from the outside in. This results in the crenulated cross-section because the outside polymerizes first and is drawn more rapidly though the bath than the interior of the fiber that is still liquid. The draw-rate affects the fiber diameter and the degree of crenulation. Acetate fiber was commercially produced starting in about 1929.

Significance in the Environment:

This is a common clothing fiber.

Characteristic Features:

Acetate has a refractive index along its length of about 1.47 to 1.48 and perpendicular to its length of about 1.47 to 1.48. It has a birefringence of about 0.004 or lower and a negative sign of elongation. It exhibits irregular striations along its length due to the crenulated cross-section of the fiber.

Associated Particles:


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