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Fiber Analysis. How Fibers are Used. To identify and describe common weave patterns Fibers fall off and are picked up in normal activities becoming trace evidence. Fibers need to be collected within 24 hours. (Why?) Used to show: Fiber Type Color Possibility of Violence Point of Origin.
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How Fibers are Used • To identify and describe common weave patterns • Fibers fall off and are picked up in normal activities becoming trace evidence. • Fibers need to be collected within 24 hours. (Why?) • Used to show: • Fiber Type • Color • Possibility of Violence • Point of Origin
Misc. Fiber Information • Yarn- spun fibers that are woven together • Shedding is the most common form of fiber transfer • Natural Fibers can be identified using a microscope only in most cases.
Other Ways to Identify Fibers • Burn Test • Solubility (Solvent) Test
Natural Fibers • Animal • Wool (sheep) • Cashmere (goats) • Mohair (goats) • Angora (rabbits) • Llamas • Camels
Natural Fibers Cont’d • Plant Fibers • Cotton (Most common) • Coir • Hemp, Jute, Flax • Manila and Sisal • Mineral Fibers • Fiberglass and Asbestos
Synthetic or Regenerated Fibers • Derived from cellulose • Petroleum base. • Rayon is the most common type • Polyamide nylon is used in performance clothing
Examples of synthetic fibers • Polyester- found in polar fleece • Nylon- easily broken down by light • Acrylic- inexpensive; tends to bead or ball easily • Olefins- high performance, quick drying, and resistance to wear.
Woven Fibers • Warp- Threads arranged side by side • Weft- Threads woven back and forth (side to side)