CLASSIFICATION OF FIBRES

• Jurisdiction: Australia

Introduction ................................................................................................... [88C.300]

Natural fibres ................................................................................................. [88C.320]

Man-made fibres ........................................................................................... [88C.340]

[88C.300] Introduction

Technically a fibre is defined as being an elongate structure whose length exceeds its breadth. Fibres can be grouped according to their origin as either natural fibres or man-made fibres.

[88C.320] Natural fibres

Natural fibre may be further subdivided into those of animal, mineral or vegetable origin. The list below gives some of the more common types which may be encountered in forensic work.

Animal fibres:

(a) human hair;
(b) wool;
(c) other animal hairs based on keratin, for example, alpaca, angora, cashmere, camel, mohair, various furs, domestic pets, farm animals;
(d) non-keratin animal fibres, for example, silk, cultivated or wild (Tussah);

Mineral fibres, for example, asbestos;

Vegetable fibres:

(a) bast fibres, for example, flax (linen), hemp, jute, Ramie;
(b) leaf fibres, for example, abaca, phormium, sisal;
(c) seed fibres, for example, akund, cotton, kapok; and
(d) others, for example, coir.

[88C.340] Man-made fibres

The classification of man-made fibres is a little more complex, as precise definitions of the various generic classes vary in different parts of the world, especially between the United States and the United Kingdom. The following list is based on the scheme presented by Grieve (1990).

Acetate: Fibres made of cellulose acetate in which less than 92% but at least 74% of the hydroxyl groups are acetylated.

Acrylic: Fibres made from a man-made linear polymer that consists of not less than 85% by mass of acrylonitrile units or of acrylonitrile co-polymers. The commonest varieties of acrylic fibre have the following compositions: acrylonitrile/methyl acrylate; acrylonitrile/vinyl acetate; and acrylonitrile/methyl methacrylate.

Anidex: Fibres made from a man-made linear polymer that consists of at least 50% by weight of one or more esters of a monohydric alcohol and acrylic acid. (Note that the United States definition specifies 40%.)

Aramid: Fibres formed of long-chain man-made polyamides in which at least 85% of the amide linkages are attached directly to two aromatic rings. The best known examples of these fibres are Nomex and Kevlar.

Azlon: (United...