CLOTHING FIBERS. There are two types of fibers: Natural Fibers & Synthetic Fibers.
Part 1 background information on fibers
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Transcript of Part 1 background information on fibers
![Page 1: Part 1 background information on fibers](https://reader030.fdocuments.net/reader030/viewer/2022032716/55b535dabb61eb28258b4795/html5/thumbnails/1.jpg)
Forensic Chemistry CHS 5542
Fibers, Hairs and Related Evidence
Background Information and Terminology
Module 5- Part 1Tatiana Trejos, PhD.
Professional Science Fonsic ScienceDepartment of Chemistry and BiochemistryInternational Forensic Research Institute
Florida International University
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Forensic Fiber Examinations
Fiber examinations typically involves
both identification of the fiber type
and comparison of K/Q to determine if
there is an association or not
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Introduction to Textile Fibers
What is a fiber?
• Natural or man made material that is the basic element of textiles
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Natural Fibers
Animal•Silk
• Fibroin
•Wool• Keratin
•Hair Fibers• Keratin
Vegetable• Seed Fibers
Cotton, kapok, coir
• Bast (Stem) Fibers Flax, hemp
• Leaf Fibers Manila, sisal
Mineral• Asbestos
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Animal (Protein) Fibers
• Protein• Greek word “proteios” meaning “first”
• Chain-like molecules • Union of α-amino acids joined with peptide
linkage
H
• H2N-C-COOH
R• Acidic and basic group attached to α-carbon atom
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Silk
• Composed of fibroin• Very different to keratin
• Continuous filament• Transfer during contact is unlikely
Image source: http://micro.magnet.fsu.edu/primer/techniques/dic/dicgallery/images/wildsilkfiberssmall.jp
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Wool
• Keratin• Staple fiber
• Scaled surface• Readily transferred
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Wool
Epicuticle
Cortex
Endocuticle
Exocuticle
Cuticular scales
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Hair Fibers (animal)
• Goat Family• Mohair (Angora goat – Capra hircus
aegagrus)• Cashmere (Asiatic goat – Capra hircus
laniger)
• Camel Family• Dromedary Camel – (Camelus bactrianus) • Alpaca – (Lama Pacos)• Vicuna – Undercoat hair (similar in all
ways to cashmere)
• Fur Bearing Animals• Angora Rabbit
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Vegetable Fibers
• Categorized by the section of the plant from which they are harvested• Seed• Bast (Stem)• Leaf
• Chemical composition dependent on source
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Vegetable Fiber Principal Constituents
• Cellulose• Hemi-Cellulose• Lignin• Pectins
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Seed Fibers
• Cotton – genus Gossypium• Produces flower, which falls off leaving
boll (pod)• Boll contains seeds with immature
fibers attached• As the fibers mature, the boll expands
and breaks open
• Kapok – Ceiba petrandra • Unsuitable for yarns, formally used as
filling
• Coir• Outer husk of coconut• Mostly used in twine
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Stem (Bast) Fibers
• Flax (linen) – Linun usitatissimum• Over 6,000 years old
• Ramie – Boehermeria nivea• Tablecloths
• Hemp – Cannabis sativa• The term “hemp” is used to describe other
fibers• Jute – Corchorus capsularis
• Ropes and cordage
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Leaf Fibers
• Sisal – Agave sisalana• Ropes, cordage
• Abaca (Manila Hemp) – Musa textilus• Better quality ropes and cordage
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Mineral Fibers
• Asbestos (Greek for incombustible)• Chrysotile - very fine fibers (25 nm diameter)
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Man-Made Fibers
• Refers to fibers that were manufactured
• Synthetic fibers are those made from synthesized polymers• Bi-products of the petroleum industry
• Regenerated fibers are those made from regenerating naturally occurring polymers and forming the fiber with that material• Cellulose
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Common Man-Made fibers
• Nylon• Polyester• Acrylic• Polypropylene• Cellulosic
• Rayon• Acetate