The effect of temperature, humidity and oxygen on fading of Crystal Violet (CV) in nylon 6 film were studied. In the presence of moisture, the fading of CV under dark proceeded more rapidly with temperature, resulting carbinol as one of the principal reaction products. The irradiation of visible light over 500nm accelerated the fading of CV in the film, especially at elevated temperature and in the presence of humid air. Analysis using both the least square method and the principal component analysis method revealed the formation of leuco compound (CVH), leuco base (CVOH) and Michler's Ketone (MK), accompanied with the formation of another products, such as their demethylated compounds. The effects of temperature, relative humidity and oxygen on the formation of these products were discussed.
A New apparatus has been designed, which gives an accurate measurement of the rate and height of capillary rise of water in a porous material, such as fabrics, from the initial moment of contact with water. When two parallel plate electrodes are immersed in water, the increase of capacitance across the twin electrodes is directly proportional to the height of water between the electrodes. The circuit was used to detect the level of water contained in a vertical strip of fabric put between twin parallel plate electrodes and to give a good linear relation between capacitance and water level. One of twin electrodes is a thin stainless steel plate and the other tinned wire coil mounted on glass plate, which are coated with Teflon film to keep a good insulation. The progress of liquid rise in a fabric, thus the increase of capacitance is recorded automatically from the first moment of contact with the liquid. Such a water level-capacitance conversion method has a very quick response, and so we can obtain a real time record of the movement of water. Not only can it be used to study very rapid initial capillary rise, but we can determine the fiber surface characteristic and the fabric geometry effect from accurate results obtained. Subsequent papers will analyze in more detail the observed transient properties.
The suitable clothing for hot weather requires passages of moisture and heat through itself. For the purpose of evaluating the moisture transfer through clothing which is put on, basic factors of measurement are discussed. The rate of water evaporation in wet fabrics was measured by means of weight method and humidity gradient method. As thermoregulative models of perspiration, a plane heater and a thermal manikin were used. In the period of a constant water evaporation from the samples, the rate of evaporation was compared between the weight method and the humidity gradient method. The ratio of the evaporation rates was estimated as 5:2 in case of a rather low convection. However, the ratio for the two methods was influenced considerably by the convection coefficient. It is necessary to investigate in detail the effect of convection around human body on the evaluation of the moisture transfer through clothing by humidity gradient method.
A method for imparting an artificial crimp to wool fibres was developed, which consists of two processings: one is a crimp formation by draft-relaxation; while the other a stabilisation of crimps by reduction-oxidation of disulphide bonds present in wool. In this work, influences of the processing conditions upon the mechanical property of wool fibres thus crimped were investigated for establishing an optimum crimping condition. The drafting and the chemical processings brought about slight decreases in the mechanical property of crimped wool fibres, although, for example, the loss in tensile strength in the Australian Shropshire wool fibre treated in this way amounted to only 5.5%. The major reason for the decrease was found to be due to incompleteness of re-oxidation of once reduced disulphide bonds. An attempt for improving this was made by re-crosslinking unreacted thiol groups with epoxides. It was found that this treatment with water-soluble multifunctional epoxide was successful.
An attempt to render wool fibres an excellent crimp and a high degree of shrink resistance was made by combining a shrinkproofing process with an artificial crimping process developed by us, which consists of two processings: one is a crimp formation by draft-relaxation; while the other a crimp stabilisation by reduction-oxidation of disulphide bonds present in wool. For the shrinkproofing, the chlorination/Hercosett resin process was employed. This work was carried out to know which one of these processes should be, in advance, applied in order to get successful results. It was found that, when the crimping process was applied, in advance, the crimp characteristics and the shrink resistance of wool fibres became much better and the mechanical property of wool fibres remained almost unchanged. These results can be attributed to the fact that the fibre was completely encapsulated by a smooth Hercosett resin film and had high disulphide crosslink densities. In addition, the processing technology established by us was proved to have an advantage that a continuous processing machine can be easily constructed. Wool sliver was obtained by using this machine and the performance of it was demonstrated.