Synthesis and characterization of degradable hydrogels formed from acrylate modified poly(vinyl alcohol) macromers

Poly(vinyl alcohol) was modified with pendant acrylate groups to create a multifunctional macromer that is crosslinkable via photopolymerization and degradable through hydrolytically cleavable ester groups within the crosslinks. The chemistry and functionality of the macromer, as well as the polymerization conditions, were varied to produce hydrogel networks with a wide range of physical properties and degradation behavior. The resulting networks were characterized by measuring the volumetric swelling ratio and mass loss profiles with degradation time. Experimental results show that the volumetric swelling ratio increases exponentially during degradation of these gels, and this increase can be predicted through a pseudo-first order reaction depending only on the kinetic constant for hydrolysis and the number of degradable links in the crosslinker. Coupled to the hydrolytic degradation, the network structure also influences the mass loss or erosion profile and, ultimately, the overall time for degradation.