Physicochemical Studies on the Surface of Polyamide 6.6 Fabrics Functionalized by DBD Plasmas Operated at Atmospheric and Sub-Atmospheric Pressures.

Larissa Nascimento,Richard Landers,Rodrigo Pessoa,Fernando Gasi,Argemiro Da Silva Sobrinho,Mariana Fraga,Eduardo Aragão,William Chiappim,Gilberto Petraconi

doi:10.3390/polym12092128

Abstract

This work proposes the use of a dielectric barrier discharge (DBD) reactor operating at atmospheric pressure (AP) using air and sub-atmospheric pressure (SAP) using air or argon to treat polyamide 6.6 (PA6.6) fabrics. Here, plasma dosages corresponding to 37.5 kW·min·m−2 for AP and 7.5 kW·min·m−2 for SAP in air or argon were used. The hydrophilicity aging effect property of untreated and DBD-treated PA6.6 samples was evaluated from the apparent contact angle. The surface changes in physical microstructure were studied by field emission scanning electron microscopy (FE-SEM). To prove the changes in chemical functional groups in the fibers, Fourier transform infrared spectroscopy (FTIR) was used, and the change in surface bonds was evaluated by energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). In addition, the whiteness effect was investigated by the color spectrophotometry (Datacolor) technique. The results showed that the increase in surface roughness by the SAP DBD treatment contributed to a decrease in and maintenance of the hydrophilicity of PA6.6 fabrics for longer. The SAP DBD in air treatment promoted an enhancement of the aging effect with a low plasma dosage (5-fold reduction compared with AP DBD treatment). Finally, the SAP DBD treatment using argon functionalizes the fabric surface more efficiently than DBD treatments in air.

Highlights

Nylon 6.6, known as polyamide 6.6 (PA6.6), is a copolyamide prepared from a mixture of a hexamethylenediamine and adipic acid [1]
The field emission scanning electron microscopy (FE-SEM) images showed superficial changes in the physical microstructure of the fabrics, with a more significant ablation occurring in the sample 1 (S1) sample due to the atmospheric pressure
The apparent contact angle measured in the initial moments after treatment with plasma dielectric barrier discharge (DBD) showed the hydrophilicity of all PA6.6 fabrics, regardless of the pressure or the plasma chemistry used

Summary

Introduction

Nylon 6.6, known as polyamide 6.6 (PA6.6), is a copolyamide prepared from a mixture of a hexamethylenediamine and adipic acid [1]. Despite the excellent aforementioned properties, due to their nature, PA6.6 fibers have weaknesses in terms of hydrophobicity and low surface energy, which reduce clothing comfort, coloring, and adhesion properties for large-scale industrial applications [10,11]. These issues generate high economic and environmental costs for the textile industry, mainly related to chemical pretreatment that consumes large amounts of chemical compounds, water, and energy [12]. Chemical treatment is used as a method of the functionalization of PA6.6 fabrics, i.e., it creates new functionalities for textiles, in many cases enabling new applications [9,13]

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Results

Conclusion