Effects of the molecular structure of graft-quaternization double modified chitosan on the functional properties of electrospun antibacterial nanofiber

Abstract

Graft polymerization-quaternization double modification has become a new effective method for preparing antibacterial chitosan (CS) in recent years. To improve the properties of double modified CS, the effects of molecular structures of amino-containing acrylate (ACA) monomer grafted onto CS (CS-g-PACA) and a quaternary ammonium reagent used for the quaternization of CS-g-PACA have been investigated in the study. A series of ACA monomers, i.e., dimethylaminoethyl methacrylate (DMAEMA), diethylaminoethyl methacrylate (DEAEMA) and 2-(tert-butyl amino)ethyl methacrylate (TBAEMA), were firstly grafted onto the molecular chain of CS. Then, CS-g-PACA was quaternized by various quaternary ammonium reagents, i.e., three kinds of chloralkane include 1-chlorobutane, 1-chlorooctane and 1-chlorododecane. The modified CS was blended with PVA to prepare nanofiber membranes by electrospinning. The major functional properties of the nanofiber membranes, e.g., fiber morphology, thermal stability, tensile property, water stability, and inhibition of E.coli and S.aureus as representatives of gram negative and positive bacterial, were evaluated systematically. The results showed that when ACA and chloralkane were TBAEMA and 1-chlorobutane, respectively, the graft-quaternization double modified CS/PVA blend nanofiber membrane possessed a more uniform and smooth fiber structure, higher thermal stability, tensile strength, water stability, and better inhibition function to the bacteria. For instance, the diameter of the fiber could reach ~ 180 nm and tensile strength of the fiber membrane could touch the value of 20.1 MPa as well. The inhibition rate of E.coli and S.aureus was as high as 95.9% and 99.6%, respectively. Double modified CS nanofibers have shown great potential to be used as biocompatible and environment-friendly medical and hygiene textiles.

Graphical abstract