Development Of Wool Fabrics Based On Hygroscopic-heating Fibers

Traditional winter clothes with fillers as the main way to keep warm are thick and bulky.Although the method can keep warm,the aesthetic is greatly reduced.Moreover,in the winter,the vapor and liquid sweat produced by the human body are extremely difficult to pass through the heavy clothes to disperse into the air and often gathering inside the clothes,which gradually makes people feel cold and wet.Researchers usually use functional fiber materials and fabric structure to develop light and warm winter clothes.At present,the hygroscopic-heating fiber is the ideal material for making winter warmth clothes.It can achieve the effect of heating and warmth by absorbing latent sweat or apparent sweat produced by human body and generating heat accordingly.In this paper,two kinds of fibers with hygroscopic-heating property were used as basic materials to design and develop the wool fabrics with hygroscopic-heating and thermal properties,one was polyacrylate fiber(EKS fiber)and the other was polyacrylic acid fiber(Shuresi fiber).And its hygroscopic-heating property and thermal comfort were tested and discussed.To this end,this paper carried out the following research work.1.The structural characteristics of two kinds of fibers were tested,and the inner cause of their hygroscopic-heating properties was analyzed.The surface structure,aggregate structure,macromolecular structure,moisture absorption and desorption properties,hygroscopic-heating property of two kinds of fibers and common acrylic fiber were tested.The results showed that the highest temperature of EKS fiber was about eight degrees higher than that of ordinary acrylic fiber,and the highest temperature of Shuresi fiber was about ten degrees higher than that of ordinary acrylic fiber.It was mainly because the two types of fibers had a rougher longitudinal structure and more longitudinal grooves than ordinary acrylic fiber,and the crystallinity of them was about half that of ordinary acrylic fiber,and they contained a large number of hydrophilic groups such as hydroxyl groups and amide bonds,which made their hygroscopicity better than that of ordinary acrylic fiber,so the heat generated by hygroscopicity was higher than that of ordinary acrylic fiber.2.The wool fabrics with hygroscopic-heating and thermal properties were developed based on EKS fiber.EKS fiber was the most practical way to develop fabrics by blending with otherfibers due to its difficult dyeing and low breaking strength.Firstly,this paper explored the feasibility of blending EKS fiber with other fibers,and determined the blending ratio of yarns.Three different types of yarns were finally spun.These yarns were made from 50% wool/30%Thermolite fiber/20% EKS fiber,50% wool/30% Tencel/20% EKS fiber and 100% wool.The pure wool yarn was taken as the contrast sample.Then,on the basis of spinning,single-layer fabrics and double-layer fabrics were designed and weaved,which consisted of five types of fabrics.Finally,the properties of air permeability,thermal resistance,moisture permeability,water conductivity and hygroscopic-heating of all the fabrics were tested.The tested results showed that the single-layer fabric containing Tencel fiber had better hygroscopic-heating effect compared with the pure wool fabric,which indicated the addition of EKS fiber and Tencel fiber could significantly improve the hygroscopic-heating effect of the fabric.The highest temperature of single-layer fabric containing Thermolite fiber was lower than that of pure wool fabric,but the average temperature of single-layer fabric containing Thermolite fiber was higher than that of single-layer fabric containing Tencel fiber,which indicated that the addition of EKS fiber and Thermolite fiber had no obvious effect on the hygroscopic-heating of fabric,but it was beneficial to the warmth of the fabric.It also showed that the Tencel fiber was beneficial to hygroscopic-heating effect of the fabrics,and the Thermolite fiber was beneficial to the warmth of the fabric.The CLO value and the highest temperature of the double-layer fabrics were higher than that of the single-layer fabrics,which indicated that the hygroscopic-heating and thermal properties of the double-layer fabrics were better than that of the single-layer fabrics.3.The wool fabrics with hygroscopic-heating and thermal properties were developed based on Shuresi fiber.Shuresi fiber could not be pure spinning because of its low breaking strength and poor elasticity,so it could only be blended in a small amount.The blending ratio of yarn was finally determined through the previous trial spinning,and the yarn was made from 50%wool/30% Tencel/20% Shuresi fiber.Eight types of fabrics were designed and weaved with this yarn such as plain weave,twill weave and satin weave.Finally,the properties of air permeability,thermal resistance,moisture permeability,water conductivity and hygroscopic-heating of all the fabrics were tested.The tested results showed that the eight different types of fabrics had significant hygroscopic-heating effect.At the same time,it was also found that different fabric structures had different effects on the hygroscopic-heating property of the fabric.As long as the amount of yarn per unit area of the fabric and the moisture absorption per unit time of the fabric increased,the fabric would has better hygroscopic-heat property.The different fabric structures had an influence on the thermal property of the fabric,especially the thickness and tightness of the fabric had a greater impact on the the thermal property of the fabric.4.In view of the limitation of temperature sensor testing,a new testing method was proposedin this paper,which could qualitatively analyze the hygroscopic-heat property of fabrics.The FLUCK high-resolution infrared thermal imager and temperature sensor were used to study the hygroscopic-heating and thermal properties of the fabric and the hygroscopic-heating property of the fabric under different humidity.It was found that the process of heat generation was very rapid,and heat generation of different parts was different through the observation of the process of heat generation.The heat generation of the outer area of the fabric sample was better than the inner area.Moreover,the temperature measured by the temperature sensor had obvious hysteresis,and the measured temperature was significantly smaller than the temperature measured by the FLUCK high-resolution infrared thermal imager.Through the test of heat generation of fabrics under different humidity conditions,it could be found that the temperature of fabric samples rose faster and fell faster in high humidity environment than that in standard atmosphere environment,and the highest temperature difference was about seven degrees.By studying the hygroscopic-heat process of fabric samples,the external factors affecting the hygroscopic-heat property of fabric could be more intuitively understood.This subject aimed to develop wool fabrics with hygroscopic-heating and thermal properties,and tested and analyzed the structure and properties of the hygroscopic-heating acrylic fibers and the inner cause of its hygroscopic-heating property;explored the influence of fiber materials and fabric structure on the hygroscopic-heating and thermal properties of fabrics;observed and analyzed the process of heat generation of fabrics by using new methods.Through the research of this subject,it could provide reference for the development of hygroscopic-heating materials and fabrics.