A generalized bulk-degradation model for hydrogel networks formed from multivinyl cross-linking molecules

A theoretical model has been developed to describe the degradation behavior of hydrogels formed from multivinyl cross-linking molecules. Kinetic information was incorporated into the model to predict the cleavage of the cross-links and structural information was included to describe the mass loss from the network. Mass loss from the networks was shown to depend on many parameters, such as the number of vinyl groups on the cross-inking molecule and the average number of cross-linking molecules reacted into each kinetic chain. Other parameters that influenced the mass loss profile are the weight fraction of the network that is contained in the cross-linking molecule, the propensity to form primary cycles, and the hydrolysis kinetic constant. Two other macroscopic properties, volumetric swelling ratio and compressive modulus, were examined as a function of the average number of cross-links per kinetic chain. Through this modeling approach, the degradation of many realistic systems can be understood and predicted, providing insight into the design of degradable hydrogel networks with the desired properties.