Mechanical Properties of Poly(vinyl alcohol) Hydrogels: Role of Chemical Crosslinks and Physical Junctions

The rheokinetics of gelation of poly(vinyl alcohol) aqueous solution systems with chemical crosslinks and physical junctions, including hybrid ones, has been studied. Hydrogels are obtained using glutaraldehyde and/or tetramethoxysilane as crosslinking components. It has been shown that at the initial step of gelation (until the systems reach critical gelation conversion) the efficiency of the process is determined by the concentration of the crosslinking agent rather than the chemical nature of network crosslinks. A comparative analysis of the mechanical properties of chemical, physical, and hybrid hydrogels at various temperatures is performed. Quasi-static uniaxial compression and tension tests make it possible to establish the contribution of network junctions and crosslinks to the behavior of hybrid hydrogels and their distinctive features.