MOISTURE TRANSMISSION THROUGH TEXTILES

Abstract

Abstract Moisture transmission through textiles has a great influence on the thermo-physiological comfort of the human body which is maintained by perspiring both in vapour and liquid form. The clothing to be worn should allow this perspiration to be transferred to the atmosphere in order to maintaining the thermal balance of the body. Diffusion, absorption-desorption and convection of vapour perspiration along with wetting and wicking of liquid perspiration play a significant role in maintaining thermo-physiological comfort. The scientific understanding of the processes involved in moisture transmission through textiles and the factors affecting these processes are important to designing fabrics and clothing assemblies with efficient moisture transfer in different environment and workload conditions. This paper is in two parts. Part I focuses on the moisture transmission through textile materials and it discusses the processes involved in moisture transmission and the key influencing factors at play to maintaining comfort. It is underlined that the processes which play the major role in moisture transmission in a particular situation are dependant on the moisture content of the fabric, the type of material used, the perspiration rate and the atmospheric conditions, such as humidity, temperature and wind speed. Part II is concerned with the selection of the measurement techniques which are of great importance in determining fabric factors that influence comfort. The instruments and methods used for testing purposes should adequately simulate the exact conditions for which the fabric will be used, in order to determine the effectiveness of that fabric for a particular wearing situation and environmental condition. The testing methods used and the apparatus developed by different researchers for determining moisture transmission through textiles by different mechanisms are discussed in this paper. Moreover, this part of the paper deals with the mathematical models of liquid and vapour transport through textile materials developed by several scientists in order to understand the exact phenomena involved and to predict the factors affecting the transmission under a particular condition. When designing the comfort of a clothing product for a particular application, the requirements may result from needs concerning the application, the individual wearer and the environmental conditions.