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Fiber Analysis
Question | Answer |
---|---|
What kind of evidence is fiber | class eviedence |
2 types | Natural and Man Made |
Natural Fibers | Can come from, animal, plant, or mineral. |
Man Made Fibers | Can come from synthesis or regenerated. (Lab) |
Most common plant fiber | Cotton |
Most common animal fiber | Wool |
Most common mineral fibers | fiberglass/asbestos |
How many fibers are synthetic fibers | more than half |
Examples of synthetic fibers | nylon, acrylic, polyester, olefin |
Cross section of synthetic fibers | rarely round or uniform |
Polymer | heavy molecule formed by joining together a large number of molecules of low molecular weight (monomers) |
Regenerated Fibers | made from chemically altering a natural polymer (cellulose) |
Examples of regenerated fibers | Rayon, Acetate, Triacetate |
Examining Fibers Techniques | Microscopic Analysis, Physical Analysis, Microchemical Analysis. |
Microscopic Analysis | Color, Texture, Diameter, Shape pattern, Cross section appearance, Surface characteristics |
Physical Analysis | Used when larger pieces are available, stretch strength, density |
Microchemical Analysis | Usually destructive, burn analysis, acid/base testing, solubility, infrared and visible spectral analysis |
Identification Tools | Microscope, flame test, chemical tests, chromatography, stain test, UV test. |
Microscope | fibers appear differently |
Flame Test | how a fiber burns/melts/ashes |
Chemical Tests | Acid/Base dissolve test |
Chromotography | Identify pigments in fabric |
Stain Test | Does the fabric take a dye? |
UV test | Does the fabric glow in blacklight? |
Animal Hair Test Result | Flame - smells like burnt hair, Acid - silk dissolves, Base - wool dissolves. |
Plant Test Result | Flame - smells like burnt paper, Acid - dissolves all plants |
Mineral Test Result | Flame - does not burn, Acid - dissolves Fiberglass |
Synthetic Fibers Test Results | Flame - melts, Acid - dissolves nylon |
Regenerated Fibers Test Results | Flame - melts, Acid - dissolves |
Fabric Weave Patterns | Plain, Twill, Satin |
Plain (Tabby) weave pattern | Most common, over one under one, snag resistant, wrinkles |
Twill weave pattern | Used in jeans, diagonal texture, over 2/3 and under 1, durable, dense, compact |
Satin weave pattern | 3/4/5/6 over to 1, smooth on one side and dull on other, tends to snag/break |