Abstract
A microwave technique was used to prepare a superabsorbent polymer (SAP) by grafting two hydrophilic monomers onto a polysaccharide substrate. The monomers used were acrylic acid (AA) or acrylamide (AM) and were grafted onto a pullulan (PUL) substrate to form PUL-g-AA (SAP1) and PUL-g-AM (SAP2), respectively. The monomers (AM/AA) were grafted together onto a PUL substrate to form PUL-g-(AM/AA) (SAP3). Grafting parameters such as grafting efficiency with the percentage, the conversion of monomer into polymer, gel content, water retention, water adsorption capacity, and swelling kinetics were determined. Additionally, the effect of environmental pH (2, 4, 7, 9, and 12) and sodium dodecylbenzene sulfonate (SDBS) surfactant was evaluated, where 1, 2, 3, 4, and 5 mM of SDBS was added to form SAP4 to SAP8. The FTIR results show that AM was grafted onto PUL through an aliphatic C-N bond, while AA grafting occurred through a single C-C bond. The grafting efficiency with AM was higher than with AA, as well as showing a superior gel content. Water absorbance capacity and water retention increased with the grafting of AA and AM together for SAP3. The highest absorbent capacity, water retention, gel content, and grafting parameters values were obtained with a 3 mM SDBS content and a pH of 7. The swelling kinetics showed that the increases in the theoretical and experimental swelling equilibriums were 72% and 82%, respectively, for SAP6 compared to the values of these parameters for SAP3. The water absorption capacity of the hydrogel increases upon increasing the pH to 7 and then gradually decreases. XRD demonstrated the improved crystallinity and crystalline size of the hydrogel after grafting polymerization of AM/AA onto PUL, in addition to enhanced thermal stability. On the contrary, FE-SEM demonstrated that SDBS improves the porosity and pore size of the hydrogel surface with SAP6.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
