SWELLING AND MECHANICAL PROPERTIES OF SUPERPOROUS HYDROGELS OF P(AM-CO-AA)/PEI IPNS

摘要

Superporous hydrogels (SPHs) of poly(acrylamide-co-acrylic acid) (P(Am-co-AA))/polyethylenimin (PEI) interpenetrating polymer networks (IPNs) were prepared, and their swelling and mechanical properties were investigated. Gelation time changed significantly according to the acidic condition of reactants. For neutralized SPHs, the maximum equilibrium swelling was observed around the AA weight fraction of 0.4, but the compressive strength decreased monotonically with AA concentration. At high concentration of AA and PEI, samples were easily cracked in water due to the swelling stress accumulated during water uptake. The swelling rate decreased with PEI and PAA concentration because it increased the molecular entanglement and network density formed by the ionic interaction between PAA and PEI molecules. For non neutralized SPHs, the swelling ratio decreased but the compressive strength increased with PEI or PAA concentration by the plasticization effect.