Microwave‐assisted polymerization: Inert addition and surface coating of superabsorbent polymer for improved physical properties

Abstract

Two different polymerization techniques, microwave-assisted polymerization and free radical solution polymerization, were utilized in the syntheses of superabsorbent polymers with varying amounts of acrylic acid (31-50%). Degrees of neutralization were in the range of 68-80 mol %, and clay level was varied between 0 and 5%. The base polymer produced with microwave-assisted polymerization had higher absorbency under low load (0.3 psi) than those with the free radical solution polymerization. To improve its absorbency under higher loads (0.6 and 0.9 psi), the surface coating step was implemented by using ethylene glycol diglycidyl ether as a surface crosslinking agent. Properties such as capacity, permeability, and absorbency under different loads were tested in 0.9% sodium chloride solution for the base and the surface-coated polymers. In addition, extractables and residual acrylic acid were measured to determine the reaction's efficiency. In conclusion, surface coating improved polymer properties, and the incorporation of clay imparted permeability to the polymer.

The Influence of Monomer Composition and Surface-CrossLinking Condition on Biodegradation and Gel Strength of Super Absorbent Polymer

“…However, increasing the gel strength narrows the network width and reduces absorption capacity at the same time. In this trade-off relationship, it is important to select the appropriate monomers and find the optimal polymerization conditions [ 5 , 6 , 7 , 8 ].…”

Preparation of a biodegradable superabsorbent polymer and measurements of changes in absorption properties depending on the type of surface‐crosslinker

“…The second major property of the SAP is its absorbency under load (AUL), which is the ability of the SAP to absorb water under a given pressure. The AUL improvement is accomplished through surface‐crosslinking of SAP particles …”