Forensic Examination of Fibres

James Robertson, Claude Roux, Kenneth G. Wiggins

• Publisher: CRC Press
• Year: 2017
• ISBN:
  9781351643214
• Edition: 3
• Topic: Law
• Subtopic: Forensic Science
• Index: Law

In order for forensic fibre examiners to fully utilize fibre and textile evidence during their analysis, they require not only specialised forensic knowledge but also in-depth knowledge of fibres, yarns and fabrics themselves. Production, both the chemical and physical structure, and the properties of these materials is required in order to determine the value of fibre evidence. This includes knowing production figures, fashion changes, sudden arrivals of new materials, dye variability, and numerous other factors that may have a bearing on the information obtained.

Fully updated with the latest advances, Forensic Examination of Fibres, Third Edition continues in the tradition of the First (1992) and Second Editions (1999) as the premier text on the subject of forensic fibre analysis. The international team of contributing authors detail the recovery of the evidence—through the different stages of laboratory examination—to the evaluation of the meaning of findings. The coverage has been considerably expanded, and all material, has been revised and wholly updated. Topics covered include examining damaged textiles, infrared microspectroscopy and thin layer chomatography, and colour analyses.

This edition also highlights the critical role of quality assurance in ensuring the reliability of the technical observations and results, and, in doing so, looks at the implications of supervisory managers and labs in the accurate and responsible analysis of such evidence.

Features include:

• 
  
  

• Outlining evidentiary process from collecting and preserving the evidence at the crime scene through the laboratory analysis of fibres

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• Detailing the latest developments and emerging technologies including Kevlar and other such advances in fibre technology

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• Coverage of a broad array of fibres both, natural (cellulose, protein, and mineral) and man-made fibres including synthetic, inorganic and regenerated

Forensic Examination of Fibres, Third Edition is a much-needed update to the classic book, serving as an indispensable reference to crime scene technicians, laboratory forensic scientists and microscopists, students in police, forensic, and justice science programs.

1

Fibres, Yarns and Fabrics: An Introduction to Production, Structure and Properties

STANLEY MACARTHUR
FERGUSSON JANE HEMMINGS

Contents

1.1Introduction

1.2Fibres

1.2.1Classification of Textile Fibres

1.2.2Fibre Production

1.2.3Fibre Characteristics

1.2.4Properties of Fibre Forming Polymers

1.3Natural Fibres – Vegetable Fibres

1.3.1Seed Fibres – Cotton, Kapok and Coir

1.3.2Stem Fibres – Flax, Jute, Ramie, Hemp, Kenaf

1.3.2.1Flax

1.3.2.2Jute

1.3.2.3Ramie

1.3.2.4Hemp

1.3.3Leaf fibres – Sisal, Hemp (Manila and New Zealand)

1.3.3.1Hemp-Abaca (or Manila Hemp) and New Zealand Hemp

1.3.3.2Sisal and Henequen

1.4Natural Fibres – Animal Fibres

1.4.1Wool

1.4.1.1Hair fibres or Speciality Wools

1.4.2Silk—Silkworm

1.4.2.1Spider Silk

1.5Mineral Fibres (Asbestos)

1.6Man-made Fibres

1.6.1Fibres Regenerated from Natural Polymers

1.6.1.1Viscose Rayon

1.6.1.2Bamboo

1.6.1.3Improved Forms of Viscose

1.6.1.4Esters of Cellulose

1.6.1.5Regenerated protein fibres

1.6.1.6Alginate Fibres

1.6.2Synthetic Fibres

1.6.2.1Polyesters

1.6.2.2Polyamides

1.6.2.3Polyolefins

1.6.2.4Polyvinyl Fibres

1.6.2.5Polyurethane Fibres

1.6.2.6Aramides

1.6.2.7Polyvinyl Alcohol Fibres

1.6.2.8Inorganic Man-Made Fibres

1.7Bicomponent Fibres

1.8New Fibres

1.9From Fibre to Fabric

1.9.1Introduction

1.9.2Yarns

1.9.2.1Types of Yarns

1.9.3Fabrics

1.9.3.1Woven Fabrics

1.9.3.2Knitted Fabrics

1.9.3.3Pilling

1.9.4Non-Woven Materials

1.9.4.1Leather

1.10Conclusions

Acknowledgments

References

Further Readings

Textbooks

1.1Introduction

If forensic fibre examiners are to fully exploit fibre and textile evidence during analysis they require not only specialised forensic knowledge but also knowledge of fibres, yarns and fabrics. Production, structure (both chemical and physical) and the properties of these materials is required in order to assess the value of fibre evidence. It is necessary to also know production figures, fashion changes, sudden arrivals of new material/s, dye variability and other factors that may have a bearing on the information obtained.

What follows is a summary of fibres and the textiles that can be constructed from them. Information can also be obtained from catalogues, journals and texts, examples of which are listed at the end of this chapter.

1.2Fibres

The fundamental use of textiles by ancient man was for the purpose of protection and the initial textile used was the animal skin. As man became more sophisticated textiles became a way of showing status in wealth and society. Rapid population gtrth since World War II and consumerism has seen a rapid expansion of textile products from synthetic sources. Without synthetic textile products world production of natural fibres would be unable to satisfy world consumer demand for fibres and their products.

The common misconception is that textiles relate in the main to apparel and home furnishings. There are however many other applications. These applications can be in the industrial, medical, aerospace and automotive industries. Fibre types and processing routes vary depending on the industry of application. Table 1.1 lists examples of the wide variety of applications for textile products in the ever-changing world of industry.

Table 1.1Use of Textiles in Various Industries

Industry	Uses
Medical	Bandages, swabs, sutures, absorbent cloths
Transport	Inflatables, ropes, canvas, sails
Mining	Conveyor belts, flexible ducting, sacks
Sports	Windproof fabrics, playing surfaces, Equipment
Furniture	Upholstery, netting, bedding, wadding
Horticulture	Netting, shade cloths, hail protection, Twine
Clothing	Sewing threads, hats, garments, shoes
Water	Hoses, membranes, filters
Chemical	Filter fabrics, vat liners, overalls
Architecture	Awnings, carpets, wall coverings, drapes
Aerospace	Glider fabric, parachutes, composites
Paper Making	Filtration aids, conveyors, felts
Automotive	Deat belts, drive belts, interior trims, insulaion
Civil Engineering	Road construction, retaining walls, soil separation, slings
Agriculture	Animal coats & collars, sacks, flexible silos
Defence	Camouflage, clothing, ballistic vests

1.2.1Classification of Textile Fibres

The basic component of a textile is a fibre. At the basic level all fibres fall into one of two categories: natural fibres and man-made fibres. Natural fibres fall into three chemical classes:

•Cellulose based fibres (from the seeds, stem and leaf of plants)

•Protein based fibres (from the hair, wool or silk of animals)

•Mineral based fibres (the only naturally occurring mineral fibre is asbestos the use of which is banned in many countries)

Man-made fibres are manufactured and fall into three classes:

•Regenerated fibres (those formed from naturally occurring fibre-forming polymers, such as viscose from cellulose)

•Synthetic fibres (those formed from non-renewable sources, such as polyester)

•Inorganic fibres (those formed from inorganic materials, such as carbon and glass)

Classification of fibres at this broad level is summarised in Figure 1.1. A more detailed breakdown within each class will be given as each is considered throughout this chapter.

Figure 1.1Broad classification of natural and man-made fibres.

1.2.2Fibre Production

Originally all textiles were composed of natural fibres, such as cotton, wool, silk, flax and jute. With the increasing demand for fibres that could perform a variety of functions, the invention and production of man-made fibres emerged. The first man-made fibre introduced in 1911 was rayon, which was a transformation of the naturally occurring polymer cellulose. The creation of synthetic polymers in 1930 made possible the production of organic synthetic polymer fibres. The first man-made synthetic polymer fibre was nylon in 1939. The development of new fibres continues even today (see Chapter 11) as advancing technical innovations expand fibre and fabric manufacturing processes. These innovations have resulted in more efficient manufacturing processes giving rise to a wider variety of products at lower cost to the consumer.

As demand has shaped the qu...