Fabrication and characterization of nanofibrous polyacrylic acid superabsorbent using gas-assisted electrospinning technique

Most commercially available hydrogels have a low surface to volume ratio due to the spherical or pseudo spherical geometry, which highly affects the corresponding swelling properties of the hydrogels. In this study, a nanofibrous superabsorbent were prepared using the gas-assisted electrospinning of Poly(acrylic acid) (PAA). The morphology of the nanofibrous hydrogel and its effect on the swelling performance were investigated. For this purpose, different concentrations of PAA solutions, operating conditions for the gas-assisted electrospinning technique, as well as cross-linking agent (1,4-butanediol diglycidyl ether) were studied. Moreover, sodium hydroxide (NaOH) was used to neutralize the PAA solutions in different contents. Fourier-transform infrared spectroscopy was used to investigate the hydrogel structure and the chemical cross-linking reaction. The scanning electron microscopy (SEM) was used to investigate the fibers morphology. SEM results confirmed the nanofiber formation using the gas-assisted electrospinning in this work. Free absorption, absorption under load, and the dynamic mechanical properties behavior of the specimens were investigated, demonstrating that the specimen prepared using 9 wt% PAA, 30% neutralized by NaOH solution, electrospun at 20 mu L/min, and cross linked by 1,4-butanediol diglycidyl ether had the highest swelling ratio, up to 90,000% and 30,000% for distillated water and standard NaCl solution, respectively.