Effects of the geometical form of silk fabric on absorbing rate of moisture were investigated. For the sake of comparison, fabrics made from other textile materials were also examined. The fabric weight was measured using electric balance and computer system, at the room temperature of 20°C, the relative humidity of 65%, and at the same time, temperature of the fabric surface and wind velocity near the fabric was measured.
As the fabric absorbs moisture, it's weight increases rapidly, it's temperature rises, and the air flow occurs near the fabric to upward direction.
The absorbing rates which are derived by the first order reaction rate, are inversely proportional to the fabric length and to the number of the layers. This relation between the fabric length and the rate of moisture absorption can be explained in terms of the empirical heat transfer theory. The lighter fabric has larger ks. values regardless of the kind of fibers. The absorbing process could be characterized by the product ks·xd, where xd is the fabric weight after drying. The ks·xd values decreased in the order cotton>linen>silk>wool. This order conforms to the increasing order of the absorption curve of moisture at 20°C. The absorbing rates were larger than desorbing rates in most fabrics, especially in silk and cotton fabrics. This would be closely related to the large hysteresis of the sorption and desorption curves in high humidities.