Influence of chemical treatment and drying method on the properties of cellulose fibers of luffa sponge

The exploration of modified luffa sponge (LS) cellulose fiber in the field of polymer composite can contribute to the development of high-performance and lightweight composites. In this study, two chemical treatments (10% NaOH-20%CH3COOH (Method 1) and 10%NaOH-5%Na2SO3 ( Method 2)) and two drying methods (air drying and freeze-drying) were used to treat LS. The microscopic characteristics and physical properties showed that Methods 1 and 2 caused shrinkage of the LS fibers and increased their fiber density by 30.6% and 15.0%. Mean-while. freeze-drying kept the cells of modified LS fibers full and decreased their fiber density by 5.0% and 21.0%, respectively.The tensile properties test analyses indicated that freeze-drying further increased the elongation at break values of modified LS fibers by 25.3% and 17.7%, respectively. The moisture absorption analyses showed that freeze-drying could further decrease the moisture absorption ratios of modified LS fibers by 25.8% and 35.8%, respectively, which was useful for improving the dimensional stability of composite materials. Moreover, the thermogravimetric analysis reveals that freeze-drying increased onset degradation temperatures of the modified fibers by 24.0 degrees C and 6.7 degrees C, which was beneficial to improve the thermal stability of the composite material. (C) 2021 Published by Elsevier B.V.