Cellulose as a polymer

A detailed Summary of Cellulose as a polymer

Cellulose is a polysaccharide found in the cell walls of plants. It consists of long chains of beta-D-glucose molecules linked by 1-4 glycosidic bonds which were formed by condensation polymerisation. These glycosidic linkages encourage the polymer chains to adopt a linear structure. The celluose molecule consists of a number of these polymer chains joined together by hydrogen bonds

Cotton is an excellent source of cellulose . Each cotton fibre is just a single cell. The cell wall is made of cellulose, containing approximately 9000 glucose molecules. The polymer chains themselves held by the hydrogen bonds chains are aligned in bundles, called microfibrils orientated along the fibre. Cotton is highly crystalline. This means that most of the glucose chains of the cellulose are closely packed in a regular way, making it a tough and fibrous polymer. So it follows that cotton fibres are stiff and have a high tensile strength which means that the are not likely to break when stretched. Cellulose itself has a large number of hydroxyl groups on the polymer chains and so cotton is a able to absorb a large amount of water without feeling wet.

A number of different cellulose-based artificial fibres were manufactured in the ea

rly twentieth century. The idea behind this was to make full use of and add to the properties of cellulose fibres such as cotton. The processes involved usually aimed to increase the crystallinity of the fibre. These were manufactured by making derivatives.

Cellulose can be esterified with a mixture of acetic acid (ethanoic acid) or ethanoic anhydride and concentrated sulphuric acid to give cellulose triethanoate or Tricel. Tricel or its sister fabric Dicel are not very popular because of their properties which make them difficult fabrics to wear on account of their low water absorbency and so low breathability. They have a very plastic feel on account of the polymer chains no longer being held together by hydrogen bonds and that the fabrics are shiny, although they are crease-resistant.

The early manufacturing processes were clumsy, unmanagable and complex, not to mention costly with the need to recover some materials. Most of the chemicals involved either reactants or products were very hazardous and expensive to dispose of safely without contributing to air or water pollution. This along with the increase in competition from other manufacturers led to deterioration in the production of cellulose-derived polymers until Tencel (also known as lyocell) was launched. The initial renewed interest in cellulose as a renewable raw material came as a result of the 1973 oil shock. This resulted in the industry being forced to direct its attention away from oil-based fabrics towards renewable resources. Lyocell is cost effective as it requires no derivatives, is considerably str

Some common words found in the essay are:
, Tricel Tricel, polymer chains, cuprammonium process, hydrogen bonds, cellulose xanthate forced, acid ethanoic, held hydrogen bonds, sodium cellulose xanthate, crystallinity strength, fibres cotton, sodium cellulose, held hydrogen, process involves, strength lyocell,

Approximate Word count = 1076
Approximate Pages = 4 (250 words per page double spaced)

Category: Science