WOOL RESEARCH

Otago Daily Times, Issue 23858, 12 July 1939, Page 7

WOOL RESEARCH

ACTIVITY OF SCIENTISTS INCREASE IN CHEMICAL KNOWLEDGE ADDRESS BY PROFESSOR SOPER The considerable activity in the field of wool research during the past few years was outlined by Professor F. G. Soper, in an address last night at a joint meeting of the Otago branch and the Agricultural branch of the Royal Society of New Zealand. Professor Soper said that the activity could be attributed to three causes, the formation of search organisations, the threat of staple fibre and the increasing scope o f chemical and physical knowledge. “ The last few years,” he said, “ have seen the formation of the International Wool Secretariat, whicl was established in August, 1937, with representatives from .' ustralia. South Africa and New Zealand. Its objective is the further ance of the interests of the wool industry. At about he same time the wool manufacturers of New Zealand formed, with Government help, a New Zealand Wool Manufacturers’ Research Association, attending particularly to the problems which arise on the nanufacturing side. This Research Association has been running for about a year and a-half, with its headquarters at the Otago University. Although quite distinct Lorn the Wool Secretariat, which is fi: .need by statute:., levies on nil wool exported from the wool producing countries of Australia, Ne-" Zealand and South Africa, the objects of both these organisations are ultimately the same. Both are vitally interested in demonstrating the advantages of the natural fibre against . hose of the artificial fibre and every step forward of +he manufacturer results in an increased demand for wool and so benefits the producer.” Atomic Structure of Wool Professor Soper described the purely scientific aspects of worn structure down to the atomic architecture of the wool molecule. That knowledge, he said, had largely accrued from the application of X-rays which showed that when wool was stretched, something happens to the arrangements of the atoms themselves in the fibre. When the strain was relaxed the atoms returned to their original position. No other fibre did that. If cotton was stretched there was some elasticity because the fibre was like a flat twisted tube, but if stretching was continued there was ultimately a slip of the internal parts of the cotton fibre and the original length was not regained. Wool fibre was unique, possessing the properties of a molecular spring. It was that fact which accounted for the way wool garments recovered their shape on being left for a few days. It also accounted for the fact that under appropriate chemical treatment wool fibres might be stretched and then fixed at their extended length without power of recovery. That ,was important in the shaping which occurred in good tailoring. The molecular process was the same as that occurring in the permanent waving of hair. Another important property of wool, Professor Soper said, wds its scaly structure.’ The strength of'a piece of yarn depended on the friction between the individual fibres and the strength of a yarn might be increased by increasing the twist of the yam. To get the same strength using a smooth fibre, the twist must, other things equal, be greater than that in a wool yam. For a certain strength a wool yam might be looser, and it was that looseness that was connected with the warm properties of wool. Extensive research had shown that under still conditions the main factor in textiles which prevented loss of heat was the thickness of the fabric, the best heat insulator being the air locked up in the. interstices of the fabric. Because of the looseness of its yams wool fabrics held much air, and that made wool, weight for weight against other fabrics, the excellent heat retainer it was. Rubberising of Wool “ Recently an advance has been made which increases the friction of one wool fibre against another.” said Professor Soper. “This is the process of mbberising, in which a partial coating of rubber is given to the fibre. This allows of still looser yams, and where fabrics are subjected to much wear, as in carpets, extremely beneficial results have been obtained. The fatigue strength of the wool has been increased and fluff due to wear has been practically eliminated. “A further valuable property of wool is the heat it gives out when it absorbs water vapour. The amount of water vapour absorbed depends on two things—the amount of water vapour in the air and the temperature. For a constant amount of water vapour in the air, the lower the temperature the more water is absorbed'by the wool. Since the absorption is attended by evolution of heat, wool taken from a warm temperature to a temperature, where the amount of water vapour In the air is the same, absorbs water vapour and gives out heat. Hence, wool acts as a temperature regulator for the person wearing it ” Disadvantages of Wool The lecturer then directed attention to the other side of the picture —the disadvantages of wool and the work which had been done to overcome them. These disadvantages were few and relatively minor With respect to susceptibility to moth attack, Professor Soper said that completely non-odorous and permanent protection was now available. The story might be said to have started when Dr Meckbach was given as a wedding present a settee, covered in green woollen material—green, because moths never attacked green cloth. On that occasion they did and Dr Meckbach, who was a German chemist, was started on a profitable line of work In 1917 he treated about 100 pieces of cloth in various ways, and placed them in cases with moth-infested rags. After six months, all were fcadlv moth-eaten except one which had been dyed with Martius Yellow. Martius Yellow was one of the earliest discovered coal tar dyes and was later replaced by other yellows more stable to light and washing. All greens in the early days contained considerable amounts of Martius Yellow and it was that component of the green dye which had given rise to the belief that green materials were not susceptible to moth attack. When Martius Yellow was no longer manufactured, being replaced by better dyes, the greens were no longer moth-proof. The war against moth attack was greatly extended by the Bayer Company of Germany, who searched successfully for colourless, odourless substances

which could be permanently fixed to the wool just as a dye was fixed and which would confer complete immunity to moth attack. Other work along similar lines had progressed in the United States and in Great Britain and it was likely that such anti-moth treatment would become a routine procedure when it became better known.

Overcoming- Shrinkage

The other disadvantage of wool, namely, shrinkage, had also been largely overcome, Professor Soper said. Wool fibres could be stretched when wet and if they were dried in the stretched condition would remain at that length until re-wetted. They then contracted to their original length. That type of shrinkage was best overcome by wetting and drying without strain in the mill. There was, however, the other type of shrinkage which occurred when wool fabrics were kneaded or rubbed in washing. The cause of that was the scale on the wool and the elasticity. and rigidity of the fibre. The rigidity caused a fibre to penetrate between other fibres under conditions of rubbing, the scales acted as a kind of ratchet and pawl, and the elasticity allowed of extension and contraction which drew the whole mass of fibres together. In one type of anti-shrinkage treatment the wool was processed with a dilute solution of chlorine which partially dissolved the scales by ’chemical reaction. In another recent process the wool was treated with chlorine gas, a process developed by (the British Wool Industries Research Association, and come interesting effects were being obtained by mixing such shrinkage resistant yarns with normal yarns. Subsequent shrinkage caused regular pouching and puckering effects for which some future was predicted.