The removal of impurities from gray cotton fabric by atmospheric pressure plasma treatment and its characterization using ATR-FTIR spectroscopy

Abstract

Gray cotton fabric shows hydrophobic characteristics due to presence of non-cellulosic impurities in outermost layers of cotton fiber. In the present study, atmospheric pressure plasma treatment for the removal of the non-cellulosic impurities from gray cotton fabric is investigated. Gray cotton fabric is treated with air dielectric barrier discharge at different time interval, and characterized by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron microscopy (SEM). Different species formed in plasma are identified using optical emission spectroscopy. The results clearly show that the plasma treatment improves wettability of gray cotton which is due to the removal of non-cellulosic impurities and due to the formation of polar carboxylate group. Removal of wax after plasma treatment is clearly reflected in ATR-FTIR spectra as disappearance of symmetric and asymmetric stretching of alkyl group at 2852.24 and 2917.81 cm−1. Further, ATR-FTIR spectroscopy provides a fast and satisfactory assessment of removal of impurities from cotton surface when untreated and plasma-treated cotton fabric is exposed to HCl vapor and subsequently spectra are collected. We observed a strong carboxyl peak is induced at 1749 cm−1 in case of untreated cotton. While for plasma-treated cotton fabrics substantial variation in the intensity of 1641 and 1749 cm−1 peak is observed with increase in plasma treatment time. The morphological changes observed by SEM are in accordance with ATR-FTIR results. The results are compared with conventionally (alkaline scouring) treated cotton fabric. The study reveals that atmospheric pressure plasma has potential to become dry and environment friendly process to improve wettability of gray cotton fabric.