Preparation of chitosan‐g‐poly(acrylamide)/montmorillonite superabsorbent polymer composites: Studies on swelling, thermal, and antibacterial properties

Abstract

Superabsorbent composites based on chitosan-g-poly(acrylamide) and montorillonite (CTS-g-PAAm/MMT) were synthesized through in situ radical polymerization by grafting of crosslinked acrylamide onto chitosan backbone in presence of MMT at different contents. The formation of the grafted network was confirmed by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), thermogravimetric analysis (TGA), and differential scanning calorimetery (DSC). The obtained porous structure was observed by scanning electron microscope (SEM). The presence of clay and its interaction with chitosan-g-poly(acrylamide) (CTS-g-PAAm) matrix was evidenced by ATR-FTIR analysis. The morphology was investigated by both X-ray diffraction (XRD) and SEM analyses. It was suggested the formation of mostly exfoliated structures with more porous structures. Besides, the thermal stability of these composites, observed by TGA analysis, was slightly affected by the clay loading as compared to the matrix. These hydrogel composites were also hydrolyzed to achieve anionic hydrogels with ampholytic properties. Swelling behaviors were examined in doubly distilled water, 0.9 wt % NaCl solution and buffer solutions. The water absorbency of all superabsorbent composites was enhanced by adding clay, where the maximum was reached at 5 wt % of MMT. Their hydrolysis has not only greatly optimized their absorption capacity but also improved their swelling rate and salt-resistant ability. The hydrolyzed superabsorbent showed better pH-sensitivity than the unhydrolyzed counterparts. The results of the antibacterial activity of these superabsorbents composites against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), assayed by the inhibitory zone tests, have showed moderate inhibition of the bacteria growth.

Tuning the properties of alginate—chitosan membranes by varying the viscosity and the proportions of polymers

“…The degradation of the chitosan powder occurred at 329.5 °C (Table ), a temperature related to the depolymerization and pyrolitic decomposition of the polysaccharide. Similar data were observed by Ferfera‐Harrar et al . (298 °C) and by Neto et al .…”

Highly Stretchable and Highly Resilient Polymer–Clay Nanocomposite Hydrogels with Low Hysteresis

“…By comparing the relative intensity of C-O-C to N-H, it was observed that the value for PM5CHI was larger than those of PM5 and PM5cata, indicating the chemical grafting of PAM onto the chitosan backbone through etherification depicted in Scheme 3 (b). 19,50 (a) The presence of branched PAM, PAM-grafted-chitosan and the interfacial interactions within the nanocomposite hydrogels was confirmed by DSC results (Figure 4 (b)). The glass transition temperature (T g ) of the branched PAM synthesized at 60 o C was 198.2 o C, which was higher than the T g of the single-chain polyacrylamide nanoglobules (~191 o C) and the bulk polyacrylamide (188 o C), scanned at a rate of 20 o C. 51 These different T g values were attributable to the difference in chemical structure, chain entanglement degree 51 and experimental conditions.…”

Development of antimicrobial PCL/nanoclay nanocomposite films with enhanced mechanical and water vapor barrier properties for packaging applications

“…Furthermore, the antimicrobial activity of PCL/OMMTs composite films could be explained due to migration of free ammonium surfactant from PCL nanocomposite films to culture medium because intercalation of PCL inside the organoclay structure could cause the release of part of the ammonium surfactant associated to the negatively charged part of the clay [53].…”