Abstract: In general, the properties of synthetic fi bres can be engineered
to suit different end-uses when the fi bres are manufactured. Natural
fi bres, however, require various treatments in order to give them a range
of properties suitable for different end-uses. Some of the treatments
used are specifi c for the particular fi bre. For example, for wool, processes
include steam-setting to give dimensional stability to fabrics, treatments
to reduce felting shrinkage and treatments to impart resistance to insect
attack. Fibre-specifi c processes for cellulosic fi bres, such as cotton and
the bast fi bres, include mercerising, which improves properties such as
dyeing and lustre, and chemical cross-linking treatments to improve
the wrinkle recovery of fabrics. Silk is given treatments to improve
appearance retention and to modify handle. Some processes, such as
scouring and bleaching, are common to all types of natural fi bres, but the
different chemical structure of the protein and cellulosic fibres requires
very different conditions in order to avoid fi bre damage. Although many
textile products are coloured by dyeing or printing, the types of dyes and
the dyeing methods used on protein fi bres differ markedly from those
used on cellulosic materials. This chapter describes the various processes
used on the natural fi bres, together with the underlying chemistry
involved in each procedure.