1. Fiber Analysis 7

2. Crimes involving fiber evidence Homicide Battery Sexual Battery Hit and Run Burglary

3. Types of Fibers Natural= Derived from animal (Hair/Fur) or plant

4. Fibers Natural Classified according to their origin –vegetable or cellulose based Cotton, Jute, Hemp –animal or protein based Wool, Mohair, Silk –mineral class Asbestos

5. Cotton Ribbon-like with twists and hollow

6. Silk Fibers are smooth and naturally transparent

7. Wool Appear round with scale-like markings

8. Other Natural Fibers Goat –Mohair, cashmere Camel Llamas Alpacas Mink

9. Other Natural Fibers Rabbit Beaver Muskrat

10. Types of Fibers Man-made= Fibers derived from natural or man-made polymers

11. What is a polymer? A substance composed of a large number of atoms (macromolecules) arranged in repeating units of monomers

12. What is a monomer? Basic unit of a polymer

13. Types of Man-made Fibers Regenerated Fibers: Man-made but from natural sources (cotton or wood pulp to get cellulose) Ex. Rayon (First Manufactured Fiber) Acetate Triacetate

14. Rayon Soft, absorbent and dries quickly

15. Acetate Luxurious appearance, soft feel, fast drying

16. Triacetate

17. Types of Man-made Fibers Regenerated Fibers: Ex. Fiber Optics

18. Types of Man-made Fibers Synthetic Fibers= Made solely of chemicals Ex. Nylons Polyesters Acrylics

19. Nylon Strong, nonabsorbent, lustrous

20. Polyester Strong, Quick drying, Wrinkle-free

21. Acrylics Soft, warm, wool-like, quick-drying

22. Fibers Synthetic –made of polymers that do not occur naturally polyesters polyamides

23. Fiber Analysis (Easy) Jig-saw puzzle method

24. Fiber Analysis (Hard) Single Fibers Microscopic Comparative Studies 1.Microscopic comparisons of color 2.Microscopic comparisons of diameter 3.Examination for lengthwise striations 4.Examination for pitting (use Titanium dioxide to deluster fiber) 5.Look at cross-sectional shape

25. Color striations Cross-sectional shape

26. Color Analysis of Fibers Compare dyes of two different fibers Use Thin-layer Chromatography

27. Refractive Index of Fibers Look for absence of Becke Line

28. Other Tests on Fiber Flame Test Solubility Test Stain Test

29. Fiber Collection Identify, and preserve potential carriers of fibers

30. Collection Package Cloths Weapons Rugs Bedding Take adhesive tape-lifts from body