Thermal Behavior Of Bi-Layered Needle-Punched Nonwovens Produced From 100% Raw Kapok Fibers

In the production of functional nonwovens with sustainable fibers, kapok, with unique qualities, becomes an excellent candidate for the production of thermal insulation textiles. However, the development of 100% raw kapok fiber structures is a challenge, since their mechanical resistance and inter-fiber cohesion is very low. In this work, the thermal behavior of new needle punched bi-layered nonwovens produced from 100% raw kapok fibers is studied. These innovative structures were obtained through dry heat-pressing of needle punched nonwovens, developed according to a novel method designed. The results obtained have shown that the heat-pressing conditions (temperature and number of cycles) affected the thermal properties of the nonwovens and the thermal performance profile of an insulating arrangement. The bi-layered nonwoven structures reinforced in one heat-pressing cycle at 100 degrees C showed the higher thermal resistance and the lower thermal conductivity and heat flux and led to the highest delay (decrement delay) of the heat transfer from the outside to the inside of the insulating assembly and vice-versa, acting as an effective thermal insulator.