Chapter 4 A Study of
Fibers and Textiles
By Dalton Webster
Period 7
Forensics
Fiber Classification
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Fibers are either Natural or Synthetic (manmade) Fibers
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Natural Fibers are divided into seven different fibers. Animal, plant, seed, fruit, stem, leaf, and mineral fibers.
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Synthetic Fibers are divided into two different fibers. Regenerated (or modified natural) and
Synthetic polymer Fibers.
Natural Fibers
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Animals provide fibers from hair, fur and webbing. All animal fibers are composed of protein. An example is silk, and is collected from the cocoons of the caterpillar Bombyx mori.
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Plants provide fibers from seeds, fruits, stems, and leaves. Cellulose is what composes plant fibers.
Cotton is the most common plant fiber.
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Minerals are neither proteins nor cellulose. Fiberglass is a form of glass. Its fibers are very short and weak.
Synthetic (man-made) Fibers
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Categorized as regenerated fiber and polymers.
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Produced by joining monomers together.
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Regenerated mostly plant in origin. Example is
Capron
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Synthetic polymer fibers originate with petroleum and are non-cellulose based fibers. Example is
Polyester, Nylon, Acrylic, and Olefins.
Natural Vs. Synthetic
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Synthetic fibers are stronger than the strongest natural fibers.
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Natural fibers are damaged by microorganisms, while synthetic fiber are not.
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Synthetic fibers deteriorate in bright sunlight and melt at a lower temperature than natural fibers.
Cotton (Natural)
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Flattened hose appearance
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Up to 2 inches long, tapering to a blunt point
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May have frayed root
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Hollow core not always visible
Flax (Natural)
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Bamboo stick appearance
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Straight with angles but not very curved
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Nodes are visible as an X every inch or so
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Often occur in bundles of several fibers
Silk (Natural)
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Does not taper, yet exhibit small variations in diameter •
May be pairs (raw silk) with another fiber
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No internal structures
Wool (Natural)
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Surface scales may be visible
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Hollow or partially hollow core
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Fibers up to 3 inches long tapering to fine point
Man-Made (Synthetic)
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Vary widely in cross-sectional shape and diameter •
Generally straight to gentle curves
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Very uniform in diameter
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May have surface treatment that appears as spots, stains, or pits
Textiles
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Fibers are woven into textiles or fabrics.
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Weaving consists of arranging lengthwise threads side by side and close together.
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Crosswise threads are then woven back and forth in one of several patterns.
