Forensics Chapt 4 Essay

Submitted By DaltonWebster15
Words: 589
Pages: 3

Chapter 4 A Study of
Fibers and Textiles
By Dalton Webster
Period 7
Forensics

Fiber Classification


Fibers are either Natural or Synthetic (manmade) Fibers



Natural Fibers are divided into seven different fibers. Animal, plant, seed, fruit, stem, leaf, and mineral fibers.



Synthetic Fibers are divided into two different fibers. Regenerated (or modified natural) and
Synthetic polymer Fibers.

Natural Fibers


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.



Plants provide fibers from seeds, fruits, stems, and leaves. Cellulose is what composes plant fibers.
Cotton is the most common plant fiber.



Minerals are neither proteins nor cellulose. Fiberglass is a form of glass. Its fibers are very short and weak.

Synthetic (man-made) Fibers


Categorized as regenerated fiber and polymers.



Produced by joining monomers together.



Regenerated mostly plant in origin. Example is
Capron



Synthetic polymer fibers originate with petroleum and are non-cellulose based fibers. Example is
Polyester, Nylon, Acrylic, and Olefins.

Natural Vs. Synthetic


Synthetic fibers are stronger than the strongest natural fibers.



Natural fibers are damaged by microorganisms, while synthetic fiber are not.



Synthetic fibers deteriorate in bright sunlight and melt at a lower temperature than natural fibers.

Cotton (Natural)


Flattened hose appearance



Up to 2 inches long, tapering to a blunt point



May have frayed root



Hollow core not always visible

Flax (Natural)


Bamboo stick appearance



Straight with angles but not very curved



Nodes are visible as an X every inch or so



Often occur in bundles of several fibers

Silk (Natural)


Does not taper, yet exhibit small variations in diameter •

May be pairs (raw silk) with another fiber



No internal structures

Wool (Natural)


Surface scales may be visible



Hollow or partially hollow core



Fibers up to 3 inches long tapering to fine point

Man-Made (Synthetic)


Vary widely in cross-sectional shape and diameter •

Generally straight to gentle curves



Very uniform in diameter



May have surface treatment that appears as spots, stains, or pits

Textiles


Fibers are woven into textiles or fabrics.



Weaving consists of arranging lengthwise threads side by side and close together.



Crosswise threads are then woven back and forth in one of several patterns.

Warp