The Chemistry of Textile Fibres

Robert R Mather, Roger H Wardman

• Éditeur: Royal Society of Chemistry
• Année: 2015
• ISBN:
  9781782626367
• Édition: 2
• Sujet: Technology & Engineering
• Sous-sujet: Materials Science

Textiles are ubiquitous materials that many of us take for granted in our everyday lives. We rely on our clothes to protect us from the environment and use them to enhance our appearance. Textiles also find applications in transport, healthcare, construction, and many other industries.
The revised and updated 2nd Edition of The Chemistry of Textile Fibres highlights the trend towards the synthesis, from renewable resources, of monomers for making synthetic fibres. It contains new information on the influence of legislation and the concerns of environmental organisations on the use of chemicals in the textile industry. New sections on genetically modified cotton, anti-microbial materials and spider silk have been added as well as a new chapter covering functional fibres and fabrics.
This book provides a comprehensive overview of the various types of textile fibres that are available today, ranging from natural fibres to the high-performance fibres that are very technologically advanced. Readers will gain an appreciation of why particular types of fibre are used for certain applications through understanding the chemistry behind their properties.
Students following 'A' level courses or equivalent and first-year undergraduate students reading textile technology subjects at university will find this book a valuable source of information.

CHAPTER 1

The Scope of Textile Fibres

1.1 INTRODUCTION

There is a very wide range of textile fibre types available in the marketplace. They vary not only in chemical type but also in physical characteristics, reflecting the wide variety of applications they have. Many people relate textiles to apparel and to materials for domestic uses, such as carpets, bedding and soft furnishings, but in fact textiles also have many specialised industrial applications. These textile products are referred to as ‘technical textiles’ and are produced mainly for their functional and technical performance, rather than their aesthetic characteristics. There are no clear distinctions between apparel and technical applications either, in the sense that the ‘performance’ apparel market, for which garments are produced to meet specific requirements in terms of, for example, functionality or personal protection, is a hugely important one.

For centuries, the textile industry was comprised exclusively of natural fibres, particularly cotton, wool and silk. Indeed, in the UK the textile industry was dominated by wool, because it was not until the beginning of the eighteenth century that cotton began to be imported. Towards the end of the nineteenth century the first ‘man-made’ fibres were commercialised, these being regenerated fibres, such as viscose rayon, based on cellulose. The textile industry then made considerable technological advances from the 1930s with the development of many types of commercially important synthetic polymers. In the period since the emergence of the first synthetic polymers, the nylons and polyesters, considerable development of this class of fibres has taken place, with the aim of producing fibres of very high technical specifications.

1.2 CLASSIFICATION OF TEXTILE FIBRES

It is useful to classify the various types of textile fibres and, since many have similar chemical characteristics, the best method of classification is according to chemical type. Before the various chemical groups are established, however, the various fibre types can be broadly classed as either natural or man-made, as shown in Figure 1.1.

Figure 1.1 Classes of textile fibres.

Natural fibres fall into three chemical classes:

• Cellulosics, which are the fibres obtained from various parts of plants, such as the stems (bast fibres), leaves and seeds.
• Protein (keratin) fibres, which are the fibres obtained from wool, hair and silk.
• Mineral (the only naturally occurring mineral fibre is asbestos but its use is banned in many countries because of its toxicity).

Man-made fibres (also referred to as ‘manufactured fibres’) can also be further sub-divided into three broad groups:

• ‘Regenerated’ fibres, which are fibres derived from natural sources comprising organic polymers by chemical processing to both extract the fibre-forming polymer and to impart novel characteristics to the resulting fibres.
• Synthetic fibres that are produced from non-renewable sources.
• Inorganic fibres, such as ceramic and glass fibres.

Textile fibre types are given what are called generic names and in Europe the organisation responsible for allocating generic names is the Bureau International pour la Standardisation des Fibres Artificielles (BISFA). IUPAC nomenclature does not meet the needs of the textile industry for naming actual fibres and so BISFA established a method and published its first list of generic names in 1994. The generic fibre names are based on common chemical groups that impart characteristic properties, such as:

–CONH–	for polyamides
–COO–	for polyesters
–(CH2–CH·CN)–	for acrylics

It is possible that a particular fibre type has two generic names, a prime example being the names polyamide and nylon, which both cover nylon 6, nylon 4.6, nylon 6.6 and nylon 11. Generic names are used extensively in garment labelling and facilitate global trading, avoiding the need for countless chemical names and trade names. There are some instances, however, where trade names are used in garment labels. Often trademarks (symbol ®) are used, which can cover a broad range of fibre types and suffix names for a very specific category of a manufacturer’s fibres, so that consumers can identify particular qualities or performance characteristics with a specific manufacturer.

The European Commission, in Regulation No. 1007/2011, requires (among other things) all textile products to be labelled with the name and percentage content of all constituent fibres by reference to the recognised fibre names specified in the Regulation. The fibre names specified in the Regulation correspond to those established by BISFA. Each EU member state is obliged to implement this Regulation and in the UK its requirements are enforced under the Textile Products (Indications of Fibre Content) Regulations.

In the USA, the Federal Trade Commission (FTC) assigns generic names and there are instances of different names being used in the USA and the EU for the same fibre types, such as: elastane in the EU is called spandex in the USA, and viscose in the EU is called rayon in the USA. Unfortunately, such duplicity can lead to some confusion amongst consumers when buying clothes.

In addition to generic names, BISFA has developed a list of codes for the various fibre types, the aim of which is to facilitate communication when referring to fibres. These codes are given in Table 1.1. While these codes are widely used by professionals in industry and academia, one anomaly seems to be the code assigned to polyester. For this fibre type, BISFA has assigned the code PES, but most professionals prefer to use the code PET, which is understandable given that the chemical name for the polymer is polyethylene terephthalate.

Table 1.1 Coding system for man-made fibres.

Acetate	CA
Acrylic	PAN
Alginate	ALG
Aramid	AR
Carbon	CF
Ceramic	CEF
Chlorofibre	CLF
Cupro	CUP
Elastane	EL
Elastodiene	ED
Elastomultiester	EME
Elastolefin	EOL
Fluorofibre	PTFE
Glass	GF
Lyocell	CLY
Melamine	MF
Metal	MTF
Modacrylic	MAC
Modal	CMD
Polyamide	PA
Polyester	PES
Polyethylene	PE
Polyimide	PI
Polylactide	PLA
Polypropylene	PP
Triacetate	CTA
Viscose	CV

1.3 FIBRE PRODUCTION STATISTICS

Data for the worldwide production of textile fibres are shown in Table 1.2. The total worldwide production of textile fibres in 2013 is estimated to be almost 95 million tonnes, distributed among the principal types of fibres as shown in Table 1.2. The total world production has grown steadily by some 25 million tonnes over the 10 years to 2013, as populations have risen and general standards of living have increased, with the consumption of textiles rising from 7.5 to 9.7 kg per capita. In the early 1990s, roughly equal amounts of natural and synthetic fibres were produced, but now over twice as much man-made fibre is produced compared to natural fibre, mainly due to a rapid increase in the demand for polyester. Of the 57.5 million tonnes of man-made fibre produced in 2013, over 75% was polyester. In part, this is due to the ready availability of the technology for polyester manufacture, which has led to over-production and the consequent lowering of the price.

Table 1.2 Worldwide production of some textile fibre types, thousand metric tonnes, 2013.

Synthetic fibres		Regenerated fibres		Natural fibres
Polyester^a	46 683	Cellulosic^a	4801	Cotton^a	25 628
Polyamide^a	4341	Lyocell^d	150	Wool^a	1121
Acrylic^a	1956			Silk^a	138
Polypropylene^a	5007			Jute^c	3085
Spandex^a	420			Linen^a	245
Aramid^d	69			Ramie^c	129
Carbon fibre^d	64			Hemp^c	172
				Coir^b	753
Totals	58 540		4951		31 271

^a Fiber Organon 2014, 85(6) 95–112.

^b Data for year 2010.

^c Data for year 2011.

^d Estimated.

It is noteworthy that nearly all of the regions of the world are involved in fibre production, though over the last decade a considerable amount of synthetic fibre production has shifted to China (see Table 1.3). Whereas in 1994 13.5% of world synthetic fibre production was in China, by 2013 that proportion had increased to over 68%. Over the same period, the proportion ma...