Effect of Scouring and Bleaching on the Physico-mechanical Properties of the Hemp Fabric

Abstract

Hemp (Cannabis sativa L.) is an annual plant belonging to the Moraceae family. It is grown for its long and stronger fiber. Fabrics made from hemp fibers have obvious advantages over synthetic textiles. An effective attempt has been made to see the effect of scouring and bleaching on the physico-mechanical properties of the hemp fabric. In this study, sodium hydroxide was used for scouring and hydrogen peroxide was used for bleaching. After the scouring, it was found that the tensile strength of the fabric decreased, but elongation increased due to the removal of impurities and non-cellulosic components. Removal of non-cellulosic impurities enhanced the softness, compactness, and crease recovery angle of the fabric. After scouring, there was also a noticeable increase in the whiteness index. On the other hand, there was a significant increase in the whiteness index after bleaching, but the tensile strength and thickness decreased due to the acidic nature of hydrogen peroxide, which weakened and deteriorated the surface of the fabric, as confirmed by the result of Scanning electron microscopy. Furthermore, it was found that bleaching with a 5% concentration of H₂O₂ has an unfavorable impact on the physico-mechanical properties of the hemp fabric, whereas scouring with a 2% concentration of NaOH improves most of the physico-mechanical properties of the hemp fabric.