Mechanical strength of hydrogel in the order, nature of monomer, crosslinking density, ionization

What is it about?

The rate of network formation and the mechanical strength of hydrogel were investigated as a function of acidic nature of monomer, pH level of solution, concentration of a crosslinking agent, and the presence of EDTA. Shear storage modulus (G') was monitored during the free radical crosslinking polymerization.

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Why is it important?

Mechanical strength of hydrogel is generally weak especially when it is swollen. In this paper, it was investigated how the stronger hydrogel can be prepared. As the pKa value of monomer is higher, its mechanical strength was improved - maximum value of G' (Pa) during the polymerization was about 20,000 in acrylic acid, 6,000 in 2-acrylamidoglycolic acid, and 400 in 2-acrylamide-2-methyl-1-propane sulfonic acid, at the condition of 1 Hz shear rate, 1% strain, and about 20 wt% of solid concentration. Most effective choice in improving the strength of hydrogel in the order, acidic nature of monomer, concentration of a crosslinking agent, and pH level of solution.