Structures and properties of thermo-regulated knitted fabrics

Microencapsulated n-octadecane was coated on the surface of cotton and cotton/polypropylene (60:40) knitted fabrics to produce thermo-regulated textiles. The structures, morphologies, phase change properties, heat flux, softness and smoothness were studied using SEM, DSC, Thermo Lab II and Smart Hand Tester, etc. It is observed that the microcapsules are inserted into the loops and adhered on the surface of fibre. The thermo-regulated knitted fabrics absorb and release 8-20 J/g of heat energy at approximately 32°C and 17°C respectively. The thermal conductivity of the coated fabric is found to be higher than that of the untreated fabric; however, the difference is small. The measured maximum heat absorption rate of the coated fabric is also slightly higher than that of untreated fabric. The heat flux of the fabrics is contributed by three factors, namely cold textile touches the hot plate and absorbs heat; heat conducts from the hot plate to the cold plate; and phase change material absorbs beat when the fabric touches the hot plate. The heat flux of MicroPCMs coated fabric is significantly higher than that of the control. The softness and smoothness of the fabric decrease after coating; however, they get better after washing with water.