Optimum Plasma Surface Treatment of Luffa Fibers

Luffa fiber is a renewable resource material with low cost and that contributes to a healthier ecosystem by its biodegradability. Its natural structure can be considered as a naturally occurring composite consisting mainly of cellulose fibrils imbedded in a lignin matrix. Surface pretreatment is necessary to maximize their potential use. In this work, plasma treatment at atmospheric pressure was carried out on the raw luffa fibers. The orthogonal method was used to optimize the plasma treatment condition. The optimal conditions were obtained at a discharge time of 10 s, power of 110 W, and electrode distance of 6 mm for the system used. The surface characterization of untreated and pretreated luffa fibers was investigated by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric (TGA) analysis. The results showed that plasma treatment did not cause significant harm to the fiber integrity and the inner cellulose fibrils were exposed from the lignin matrix. Plasma-treated luffa fibers also showed a slightly better thermal stability than the untreated fibers. Compared with chemical pretreatment, plasma treatment had a significantly shorter duration, no consumption of solvent, and improved the cellulose contents.