HAT IS WOOL?

Greymouth Evening Star, 2 November 1931, Page 7

HAT IS WOOL?

NO ONE REALLY KNOWS. Although the wool industry was one of the oldest known to mankind, it is an extraordinary fact that as yet no one knows exactly what. wool is, remarked Dr T- Marwick during a recent lecture on “Wool Research.’ “The result of this ignorance is that the treatment of wool in the production of fabrics is essentially the same today as it was thousands of years ago. It is true that we now have huge factories in which machines have taken the place of human beings and which arc producing woollen and worsted fabrics at a rate hitherto undreamtof, Lui the fact remains that these machines are merely speeding up and perfecting the methods of the hand spinner and the hand loom weaver. No fundamentally new process has teen introduced, nor has the fibre been altered in any way to produce new effects such as we find in the mercerised cotton and artificial silk. Surely, then, there is enormous scope for advance In the adaptation of the wool fibre to new processes and new uses. Why is it that it has remained for so long practically unaltered, while other lees wonderful fibres have made such startling progress in the textile world? Il is because we do uot know the nature of the fibre nor its capabilities, and until such knowledge is available wool must necessarily compete at a disadvantage with those fibres whose nature is known, and whose behaviour under any given conditions can, in consequence, be foretold with certainty.”

It has, therefore, become increasingly evident, Dr Marwick went on to say, that the problem of fundamental importance to manufacturer and producer alike is the determination of the structure and properties of the individual wool fibre- The recognition of this fact has brought about in recent years an intensive study of the subject along chemical, physical, and biological lines. Earlier investigations had suggested that wool is built up of ultra-microscopic particles or micelles very much elongated, and arranged more or less end-to-end along the fibre. Each of these micelles consists of molecules of an insoluble pro-' tein, keratin, composed of carbon, hydrogen, oxygen, nitrogen, and sulphur, and it is the precise manner in which the atoms of these various elements are linked together which gives to wool its own peculiar properties; in other words, which makes it wool as distinct from any other fibre. The question now' was how to detect this particular arrangement. The atoms whose precise method of arrangement means so much to the sheep farmer, to the manufacturer, and to the general public, are less than one-hundredth millionth of an inch in diameter. No microscope, however powerful, could even detect such infinitely small particles.

USE OF X-RAYS-Within recent years, however, X-rays, which are in reality infinitely zmall light, waves, have proved to be of the exact size necessary to ’detect the presence of particles of atomic size. The one essential feature is that these particles should possess a certain regularity of arrangement in all tin co dimensions —in other words, that they should form a crystalline structure.

Already X-ray analysis has met with maikcd succecs in determining the atomic structure of the simpler inorganic substances; and, in the more difficult field of organic chemistry, where we have to deal with larger molecules, much has also been done. It is only within the last few years, however, that substances as complicated as the proteins' have been subjected to this method of attack. As a result it has been shown that wool, in common with all animal hairs, and, indeed, all epidermal outgrowths—such as nails, horn, quills, etc. —possess a definite crystalline structure, that is, its molecules are arranged in a certain regular pattern. This molecular pattern can, moreover, be gradually changed merely by extension of die fibre. This is the most astonishing result obtained so far, and scientifically'as well as economically is of far-reaching importance. It is incidentally the explanation of the pressing of garments and the permanent waving of hair, for not only can it be produced and destroyed at will by extending and releasing the fibre in cold water —it can also be permanently set in the extended state by the action of steam-

Experiments on stretched wool show that it is more vulnerable to chemical attack than unstretched wool; it is therefore obvious that it can never be relied upon to react to any textile piocess in the same way as unstretched wool, more particularly in the presence of steam. This extraordinary molecular change also offers an explanation of the long-range elasticity of wool —a property which has not yet been utilised to its full advantage. Whereas cotton and silk have very little Hue elasticity, wool can, by suitable treatment with steam, be extended to double or contracted to half its, oiiginal length. The only other .substance, apart from the proteins, which ie capable of a similar extension is lubber, which also undergoes a change in molecular arrangement as evidenced by X-ray analysis. The examination of normal and stretched wools by these methods has led to the suggestion of a “skeleton” srtucture for wool fibre, which has already met with a considerable amount of success in explaining the observed results, and which has indicated new and fruitful lines of investigation. One of the most interesting possibilities is the determination of the size of the micelles and of the intermicellar spaces with a view to discovering the necessary conditions for fast dyeing. The dye molecules must actually ponderate into the interior of the fibre and take up their position between the micelles. II is ihoreforo of the utmost importance io know the size of the space available, and to what extent this can be altered by means of suitable reagents, to admit, the desired molecules.

REGENERATION POSSIBILITIES, Another possible line of advance lies in the regeneration of low-grade wool into a more useful fibre. A similar process has already been carried cut in the ease of cellulose derived from wood pulp, which can be converted into the various forms of fibre popularly known as “artificial silk.” This process is not strictly one of synthesis, but analogous rather to the taking to pieces of au old brick house and rebuilding it in a. more con-

venient form. The bricks in this case the cellulose units, persist throughout unchanged- The complexity of the wool molecule, which, it is suggested, consists of long zig-zag chains of atoms lying along the fibre and clinging together sideways, makes it extremcly unlikely that it will ever be synthesised commercially, but there seems no real reason why imperfect and undesirable wools should not be utilised for making a regenerated hire, which would, because of its similar properties, mix belter with wool than the cotton and other cellulose fibres in use at present. One prevalent but quite mistaken idea is that a. complete knowledge of the structure of wool will dp away with the need for the natural fibre. Nothing is further from the truth; it cannot be emphasised too strongly that increased knowledge of the material with which we arc working means increased possibilities of manufacture, increased demand for wool, and a consequent stimulus to production. The day is past when any section of the community could stand aside and carry on its work independently of the rest; wo inttsl realise that success in the wool trade demands the heartiest co-operation between the manufacturer. the producer, and the research worker and, in addition, the great muss of people who are dependent on concerted efforts of all three.