Nanoporous Sodium Carboxymethyl Cellulose-g-poly (Sodium Acrylate)/FeCl3 Hydrogel Beads: Synthesis and Characterization.

Bijender Kumar,Farha Deeba,Anuj Kumar,Kirtiraj K Gaikwad,Jaehwan Kim,Ruchir Priyadarshi,Anurag Kulshreshtha,Sauraj Sauraj,Yuvraj Singh Negi

doi:10.3390/gels6040049

Abstract

Novel sodium carboxymethyl cellulose-g-poly (sodium acrylate)/Ferric chloride (CMC-g-PNaA/FeCl3) nanoporous hydrogel beads were prepared based on the ionic cross-linking between CMC-g-PNaA and FeCl3. The structure of CMC and CMC-g-PNaA were elucidated by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) spectroscopy, and the elemental composition was analyzed by energy dispersive X-ray analysis (EDX). The physicochemical properties of the CMC-g-PNaA/FeCl3 hydrogel beads were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and thermogravimetric analysis (TGA). The swelling percentage of hydrogel beads was studied at different time periods. The obtained CMC-g-PNaA/FeCl3 hydrogel beads exhibited a higher nanoporous morphology than those of CMC-g-PNaA and CMC beads. Furthermore, an AFM image of the CMC-g-PNaA/FeCl3 beads shows granule type topology. Compared to the CMC-g-PNaA (189 °C), CMC-g-PNaA/FeCl3 hydrogel beads exhibited improvement in thermal stability (199 °C). Furthermore, CMC-g-PNaA/FeCl3 hydrogel beads depicted a higher swelling percentage capacity of around 1452%, as compared to CMC-g-PNaA (1096%). Moreover, this strategy with preliminary results could be useful for the development of polysaccharide-based hybrid hydrogel beads for various potential applications.

Highlights

Hydrogels are three-dimensional polymeric network structures with a higher capacity to absorb water due to the presence of hydrophilic groups, but which are insoluble in water
We introduced the novel nanoporous carboxymethyl cellulose (CMC)-g-PNaA/FeCl3 hydrogel beads that were developed by the ionic cross-linking of CMC-g-PNaA in the presence of FeCl3 as an ionic cross-linker, while CMC-g-PNaA
Ionic cross-linked CMC-g-PNaA/FeCl3 hydrogel beads were prepared by the cross-linking of CMC-g-PNaA, followed by the grafting polymerization of acrylic acid (AA) onto CMC, as shown in Scheme 1

Summary

Introduction

Hydrogels are three-dimensional polymeric network structures with a higher capacity to absorb water due to the presence of hydrophilic groups, but which are insoluble in water. Few polysaccharide-based hydrogel beads including alginate [12], CMC/dextran sulfate [13], calcium alginate-CMC [14], CMC-NPS [15], sodium alginate-CMC [16], alginate/Ca2+ [17], silsesquioxane/CMC [8] and cellulose nanocrystal/sodium alginate [18] have been developed with improved properties. Yang and co-workers reported CMC hydrogel beads that were prepared by the cross-linking of epichlorohydrin with CMC. Agarwal et al developed CMC-based hydrogel beads by ionic-gelation methods for drug delivery systems [14]. Ren and co-workers developed the CMC gel-based beads via blending, followed by cross-linking, and studied the effect of pH, temperature and dosage of beads on the adsorption behavior of Pb2+ [16].

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Conclusion