Radiation crosslinked polyvinyl alcohol/polyvinyl pyrrolidone/acrylic acid hydrogels: swelling, crosslinking and dye adsorption study

• Published in: Iranian polymer journal 2021-10, Vol.30 (10), p.1101-1116
• Main Authors: Rahaman, Md. Saifur, Hasnine, Shah Md. Marzuk, Ahmed, Tanvir, Sultana, Salma, Bhuiyan, Md. Abdul Quaiyum, Manir, Md. Serajum, Ullah, Nayeb, Sen, Sapan Kumar, Hossain, Md. Nazmul, Hossain, Md. Sahadat, Dafader, Nirmal Chandra
• Format: Article
• Language: English
• Subjects: Acrylic acid; Adsorption; Adsorptivity; Ceramics; Chemistry; Chemistry and Materials Science; Composites; Crystal structure; Crystallinity; Gelation; Glass; Hydrogels; Mechanical properties; Methylene blue; Modulus of elasticity; Morphology; Natural Materials; Original Research; Polymer Sciences; Polyvinyl alcohol; Radiation; Radiation crosslinking; Spectrum analysis; Stability analysis; Swelling; Thermal analysis; Thermal stability; Thermodynamic properties
• ISSN: 1026-1265; 1735-5265
• DOI: 10.1007/s13726-021-00949-2

Hydrogels were produced from mixtures of polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), and acrylic acid (AAc) using γ-radiation at doses of 3, 7, and 10 kGy and the effect of the variation in concentration of AAc within 0%–3% (w/v) on the gelation, swelling, crosslinking, thermal properties, crystallinity, mechanical properties, and surface morphology of the hydrogels were characterized and their adsorptive removal properties for methylene blue (MB) was investigated. The swelling trend was pH-dependent which was dictated by the dominance of two competing factors namely, crosslink density and hydrophilicity. Although thermal analysis showed that the presence of AAc decreased the thermal stability of the hydrogels, SEM images exhibited gradual morphological changes establishing the role of AAc as a crosslinker, and thus increasing the elastic moduli, toughness, and crystallinity of the hydrogels. However, correlation between the characterization results revealed that, in spite of AAc occupying some of the crosslinking sites within PVA–PVP networks, at low concentration (1% w/v), it could not polymerize enough to contribute to the crosslinks. FTIR spectral analysis revealed a possible gelation mechanism along with the points of interaction among the gel-components. MB adsorption capacity of the hydrogels reached a maximum of 117 mg/g following pseudo-second-order kinetics through film diffusion mechanism while the adsorption isotherm resembled most with that of Langmuir.