Synthesis of the copolymer hydrogel κ‐carrageenan‐graft‐PAAm: Evaluation of its absorbent and adhesive properties

Abstract

k-Carrageenan-graft-PAAm, a copolymer hydrogel of k-carrageenan (kC) and acrylamide (AAm), has been synthesized in aqueous medium at $ pH 7 in the presence of the initiator potassium persulfate (KPS), using microwave irradiation. The reaction conditions were optimized by varying the concentration of AAm and KPS to obtain copolymer hydrogels having different nitrogen contents e.g., %N 6.35, 10.56, and 11.05. It was observed that copolymer hydrogel having %N 11.05 gives superior adhesive properties whereas copolymer hydrogel with %N 10.56 produces superior absorbent properties in the presence of optimized concentrations of AAm (0.87 and 1.1428 mol/L respectively) and KPS (0.022 and 0.0296 mol/L respectively). The product with %N 6.35 is a soft gel (2-5% gel in 1% KCl) exhibiting low gel strength (135 g cm À2). The one with %N 10.56 showed superior swelling property and maximum swelling was observed in the alkaline pH (22 g/g). The swelling behaviors of the hydrogels were studied at different pHs (pH 1.2-12.5) as well as in 1% aqueous solutions of NaCl, KCl, and CaCl 2 . The 5% dispersion of the hydrogel having %N 11.05 in water had good binding properties with papers, polyethylene sheets, and wood pieces. To evaluate the measure of adhesive property, the viscosity and solid and liquid weights of the applied adhesive were measured. Characterization of the copolymer hydrogels was done by TGA, X-ray diffraction, 13 C-NMR, FT-IR, elemental analyses, and rheological studies.

Carrageenans from nuclear phases of subantartic Mazzaella laminarioides (Gigartinales, Rhodophyta) and graft copolymerization of alkali-modified carrageenan with acrylamide

“…Recently, studies on the application of carrageenans in drug delivery systems have gained much interest (Nanaki et al 2010;Rana et al 2011;Li et al 2013Li et al , 2014. On the other hand, copolymerization of carrageenans with vinyl monomers produces graft copolymers with new properties and applications Meena et al 2006;Pourjavadi et al 2008;Hosseinzadeh 2009;Mishra et al 2010;Sand et al 2012;Yadav et al 2012;Verma et al 2014).…”

Elasticity Study of PAAm-κ C Composite Prepared in Various κ C Content and Measured at Several Temperatures

“…This must suggest that the viscose medium has a network structure with exible polymer chains just as swollen medium [15]. Lastly, as it was predicted, the elastic properties of PAAm-κC composite are highly dependent on the (w/v)% of κC content, which directly inuences monomer interactions between PAAm and κC in the composite.…”

“…In addition, lower κC (below 1 (w/v)% of κC) content enhances the hydrophilicity of the hydrogel in PAAm-κC composite. A further increase in κC content (above 1 (w/v)% of κC content), however, results in decreased absorbancy [15]. This is probably due to an increase in the viscosity of the medium, which hinders the movement of free radicals and monomers molecules and the enhanced chance of chain transfer between PAAm and κC monomer molecules [13].…”

Green Polymer Synthesis: An Overview on Use of Microwave‐Irradiation

“…The influence of irradiation time, ÌÌÁ/ê-carrageenan ratio, reaction temperature, and initiator concentration on MMA conversion and grafting efficiency was investigated. k-Carrageenan-graft-PAAm, a copolymer hydrogel of k-carrageenan and acrylamide, has been synthesized in aqueous medium at pH 7 in the presence of the initiator potassium persulfate, using microwave irradiation [67].…”