[en] In this work, the effects of Ar and He atmospheric pressure plasma on the natural luffa fibers surface and thermal properties were investigated. Optical emission spectroscopy OES has been used to characterize the Ar and He plasmas. The pristine and plasma-treated luffa fibers were analyzed by means of scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA) and water contact angle. The SEM images show the removal of hemicellulose and lignin layers from plasma treated luffa surface, whilst preserve their integrity. This was confirmed by FTIR and XPS results. XPS analysis of the plasma treated luffa fibers revealed the formation of oxygen containing functional groups and hence the O/C ratios increases from 0.18 in pristine to 1.08 and 1.09 in He and Ar plasma treated ones, respectively. This results lead to improvement of the adhesion and wettability characteristics of luffa fiber as well as their thermal stability. Graphical abstract:

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