Evaluation on thermal and wet comfort properties of hygroscopic exothermic knitted fabric based on moisture diffused-transmission mechanism

This paper aims to study the hygroscopic exothermic behavior of fabrics, exploring the feasibility of achieving much slower and more even hygroscopic heating process by strengthened moisture transmission control. Based on the model of coupled heat and moisture transfer, the moisture diffused-transmission, 'type-ladder' mechanism was proposed, and then different moisture-absorbing and heating knitted fabrics were prepared by dissimilar finishing. The result showed that the mechanism of 'type-ladder' had the feasibility and advantages in retarding, extending and uniforming the moisture absorption and heat generation. Moreover, it was found that the inner layer of the composite finishing fabric was much more sensitive to the moisture with a faster diffusion and a closer water-fiber interaction through the analysis of the moisture transmission. By means of finishing to obtain the variation both in moisture state and diffusion, caused the fabric heating up much slowly in the continuous high-humidity micro-environment and evenly in the micro-environment with the moisture increasing until high-humidity significantly, which is further proven by the heat of desorption. These results demonstrated that hygroscopic exothermic fabric on 'type-ladder' mechanism might provide a new option fit to the actual thermal and humid comfort requirements.