Study on Physicochemical Properties and Potential Applications of Chemically Treated Luffa Sponge Fibers

To explore and expand the application of luffa sponge (LS) fiber, three methods were used to chemically modify the LS fibers. The nanoindentation (NI) results show that the LS fibers exhibit a high elastic modulus (12.4 GPa) and hardness (0.7 GPa). Upon treating the fibers with 5%NaOH-5%H2O2, the NI hardness of the fibers increases by 14.3%. However, when 10%NaOH-20%CH3COOH (method B) is used, the hardness of the cell walls decreases by 28.6%. In this case, the removal of amorphous substances from the LS fibers and the swelling reaction of the LS cellulose plays a significant role. Three chemical treatments can partially remove the hemicellulose in the LS fiber. 18%NaOH-1.6%CO(NH2)2 (method C) modifies the crystalline structure of the cellulose in the LS fibers. Gas chromatography-mass spectrometry results show that the LS fibers are rich in hexadecanoic acid (14.3%), as well as in substances, such as squalene, oleic acid, and behenic alcohol, which exhibit a high antibiofilm activity. Furthermore, method B increases the total relative content of squalene and squalane in the LS extract by 49.4%; while method C treatment allows LS fibers have the potential to be used to develop phase-change energy storage materials and anti-photoaging discoloration materials.