Application of superabsorbent polymers (SAPs) has caused broad attention due to their mitigation of autogenous shrinkage in concrete. Polyacrylic acid (PAA) hydrogels have been synthesized using AIBN as the initiator and ethylene glycol dimethacrylate (EGDMA) as the cross-linker. Swelling studies showed that increased cross-linking density prevents the hydrogel from absorbing more solution (figure1). Adding Ca2+ ions decreased the PAA gel absorbency dramatically (figure2). Further reactions were carried out with a redox initiator polymerized in water. The influence of ionic-crosslinking on SAPs swelling behavior is studied by introducing different ratios of nonionic acrylamide (AM) monomers into PAA gel. The absorption rate of solvent is studied by a vortex test. The impact of cross-linking density on the dehydration behavior of SAPs is tested under controlled humidity. Additionally, dynamic mechanical analysis (DMA) is used to obtain the stress-strain behavior of PAA-co-PAM gel with different swelling ratios.

Influence of ionic-crosslinking density of superabsorbent polymers(SAPs) on absorption/dehydration and viscoelastic behavior

246th National Meeting (2013)

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