Characterization of hydrogels formed from acrylate modified poly(vinyl alcohol) macromers

Poly(vinyl alcohol) was modified with pendent acrylate groups to form a macromer that was crosslinked via photopolymerization. Polymerization behavior was studied for several initial macromer concentrations using DSC and Near-IR spectroscopy. Under mild photoinitiating conditions (e.g. 0.05 wt% initiator and less than 20 mW/cm(2) of 365 nm light), the hydrogels polymerized to 100% conversion in less than 5 min. To characterize the network structure, the hydrogels formed from the acrylated poly(vinyl alcohol) macromer were compared to gels that were chemically crosslinked with glutaraldehyde and gels that were physically crosslinked by semi-crystalline regions introduced through freeze-thaw cycles. The equilibrium swelling ratio and compressive modulus were characterized for all of the resulting PVA hydrogels, and related to the network structure (i.e. <(M-c)over bar>) through a modified Flory-Rehner equation and rubber elasticity theory. (C) 2000 Elsevier Science Ltd. All rights reserved.