The
giant molecular chains of textile fibres have two regions; crystalline and
amorphous. Actually there is no sharp dividing line between these two regions.
Tensile strength is due to crystalline regions, and its flexibility depends on
amorphous areas; satisfactory textile fibres have these two regions balanced to
the best advantage.
The
chemical properties of textile fibre can be considered in two ways; 1st,
according to the properties of the simple units which build up the molecular
chain, and 2nd, according to the properties which hold these unite
together in the chain-molecule and also the chain-molecules in bundles.
The
two great classes of fibrous materials are the carbohydrates and proteins.
Hence, part of chemical behaviour of the cellulose fibres is due to that of
glucose unit with its alcoholic groups, and part of the behaviour of the protein
fibres is due to that of amino-acid residue with its atmospheric nature. Both
of these units contain hydrophilic groups, so that a strong affinity for
moisture may be expected. Cellulose fibres are susceptible to those reagents
which attack polysaccharides at the glycosidic linkage, and that the
polypeptides are sensitive to reagents which attack the peptide linkage.
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