Page 12 - Curriculum Visions Dynamic Book

contain the same basic molecules, do not form useful fabric fibres because their chains are branched and coiled up, and cannot be separated.
Artificial polymers
Artificial fibres, also sometimes called man-made fibres, are fibres that have been modified in some chemical way from natural fibres or created from materials not related to natural fibres.
Natural cellulose fibres can be reconstituted to make new materials. The fibre that results is artificial in the sense that it does not occur naturally in this form. However, because the new materials still contain cellulose, they are called regenerated fibres. Rayon is the main example of this.
Synthetic fibres are polymers that do not have either natural proteins or cellulose as their starting point. They almost exclusively use products obtained from petroleum. Synthetic polymers can be thought of as designer polymers.
Petroleum is a mixture of substances that readily combine into chains. Petroleum also contains a huge variety of molecules, each of different sizes, so the possibilities of producing a polymer with useful properties are good.
(Above) This is a rayon molecule. Like other polymers, it is made up of a string of repeating chemical units – rather like a long train in which all the carriages are alike.
Rayon is derived from cellulose (processed wood chips such as the ones below), which in turn is made up of a string of glucose units.
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A glucose unit (C6H12O6)