Improved antibacterial activity of hemp fibre by covalent grafting of quaternary ammonium groups.

Li Chang,Gen Pan,Yong Deng,Defang Li,Anguo Chen,Huijuan Tang,Lining Zhao,Wenjie Duan,Jianjun Li,Siqi Huang

doi:10.1098/rsos.201904

Abstract

In this study, a novel antibacterial hemp fibre grafted with quaternary ammonium groups (HF–GTA), were prepared by alkalization, oxidation, amination and quaternization multistage reactions. The chemical structure and micromorphology of the fibre were characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis and X-ray diffraction. The grafting and reaction mechanism proved to be successful, which indicated that the grafting reaction primarily occurred on the hydroxyl group of cellulose and hemicellulose in the hemp fibre, where it retained good fibrous morphology, thermal stability and hygroscopicity. HF–GTA exhibited the best antibacterial activity, where the antibacterial ratios against Escherichia coli and Staphylococcus aureus were 95.41% and 99.64%, respectively. Even after washing 30 times, the antibacterial activity was retained at 89.78% and 91.12%, indicating that HF–GTA was endowed with good washing resistance. The antibacterial activity was owing to the electrostatic reaction reducing the electrochemical potential on the cell membrane, leading to the release of cytoplasmic substances and the dissolution of cells. This study is significantly important for guaranteeing textile quality and preventing disease transmission.

Highlights

In this study, a novel antibacterial hemp fibre grafted with quaternary ammonium groups (HF–glycidyl trimethyl ammonium chloride (GTA)), were prepared by alkalization, oxidation, amination and quaternization multistage reactions
Preparation of hemp fibre grafted with quaternary ammonium groups
To increase the availability of hydroxyl groups, NaOH was used during the alkalization process, because alkalization could break the intra-molecular or inter-molecular hydrogen bonds of cellulose, and at the same time, the ester bond between hemicellulose and coexisting components will be saponified, and the ether bond will be broken under the action of OH−, and part of the coexisting components will be dissolved in alkaline solution

Summary

Introduction

A novel antibacterial hemp fibre grafted with quaternary ammonium groups (HF–GTA), were prepared by alkalization, oxidation, amination and quaternization multistage reactions. It is significative to endow hemp fibre with antibacterial properties to produce an important functional material that can guarantee textile quality and prevent disease transmission. Quaternary ammonium functional groups have been covalently grafted onto the surface of cellulose, thereby greatly improving the antibacterial properties and stability. Oyervides-Muñoz et al [20] synthesized three different ammonium salts with a carboxylic acid end group through a quaternization reaction and chemically grafted them along the chitosan backbone using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide as a carboxyl-activating agent for coupling with the primary amine groups, which significantly improved the antibacterial activity against Pseudomonas aeruginosa. Owing to the presence of quaternary ammonium groups, the antibacterial properties of the cellulose membrane were improved, where the best antibacterial ratios were 95.1% against S. aureus and 90.5% against E. coli

Methods

Results

Conclusion