Written by: V. K. Kothari and Soumyajit Sarkar
With the decrease in thickness, the structures become more compact. Contact points among the fibres can be considered to increase, making the pores more torturous. Rate of evaporation from a compact structure is relatively slow as compared to an open one. Slow evaporation will provide prolonged performance. Lower thickness resulting in denser fabric shows better performance as compared to low density thicker fabrics.
Nonwoven fabrics containing Super Absorbent Fibres can be used to increase the protection time against heat. Protective performance of assembles containing nonwovens as absorbent core has been evaluated. A number of three layer evaporative cooling fabric assemblies were designed and effects of various parameters on its performance were studied. Adding of water to the sample provides better performance than the dry sample due to evaporative cooling. Neither too high nor too low amount of added water provides satisfactory performance. Optimum performance was obtained when the amount of added water was four times the dry weight. Too tight or too much open construction of the outer layer also does not facilitate the cooling process to satisfactory level. Increasing the SAF content and basis weight of absorbent core has positive effect on the protective performance, whereas increasing the thickness of the core decreases the performances. Evaporative cooling garments can be designed using different amount of SAF and different basis weight depending on the end user requirement. Same level of performance can be achieved by using lower basis weight and higher SAF content as compared with higher basis weight and lower SAF content, but cost of the product will increase.
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