A statistical kinetic model for the bulk degradation of PLA-b-PEG-b-PLA hydrogel networks

A theoretical model has been developed to describe the bulk-degradation behavior of model PEG-b-PLA hydrogels. Utilizing a statistical approach to predict the cleavage of cross-links within these networks, the model accounts for both structural and kinetic issues during the degradation and, from direct comparison, can accurately predict the complex erosion profiles of the cross-linked hydrogels. The mass loss profiles of the cross-linked networks are shown to depend on parameters such as the order of the hydrolysis reaction, the value of the kinetic rate constant, the number of cross-links per backbone chain, and the mass fraction of network contained in the backbone as opposed to the rest of the network. Such an accurate degradation model based on fundamental parameters allows a greater understanding of the bulk-degradation process and its controlling factors.