A statistical kinetic model for the bulk degradation of PLA-b-PEG-b-PLA hydrogel networks: Incorporating network non-idealities

Experimental studies and theoretical predictions of the bulk-degradation be havior of nonideal PLA-b-PEG-b-PLA hydrogels were performed. The theoretica l predictions are based on a previously developed model to which refinement s have been made, including the incorporation of a more realistic descripti on of the crosslinked, copolymer network structure. Also, structural comple xities such as unreacted vinyl groups, multiple degradation sites along the polymer chains, and distributions in the degrees of polymerization of the crosslinks, cycles, and backbone chains that comprise the network are now i ncluded in the model. Each of these factors has a dramatic effect on the bu lk-degradation behavior of the hydrogels, and this second generation model incorporates these factors into the theoretical description of the experime ntal system with only a minimal increase in the number of parameters and co mplexity of the model equations.