Rheology and adhesive properties versus structure of poly(acrylamide-co-hydroxyethyl methacrylate) hydrogels
Résumé
This study investigates the relationship between structure, rheological properties and adhesive performances of poly(acrylamide-co-hydroxyethyl methacrylate) P(AM-HEMA) hydrogels. The microstructure and, as a consequence the rheological behavior, of polyacrylamide-based hydrogels have been modulated by varying the precursory reaction mixtures composition. Elastic G′ and loss G″ shear moduli measurements highlighted their inhomogeneous structure. Structural parameter values predicted by the rubber elasticity theory showed that P(AM-HEMA) networks are constituted by dense polymer regions interconnected by more dilute polymer ones as a result of multiple cross-linking reactions. We demonstrated that increasing the cross-linker composition allows to increase G′ values however the inhomogeneity degree of the networks is higher. Contrarily, HEMA introduction into the feed and the increase of monomers’ composition suppress the extent of PAM network inhomogeneity. Probe test tack experiments evidenced the effect of P(AM-HEMA) structure on the rheological properties and adhesion energy as well as the detachment type.
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