Fracture of Model End-Linked Networks*

Advances in polymer chemistry over the last decade have enabled the synthesis of well-defined networks that exhibit homogeneous structure. These well-defined polymer gels create the opportunity to assess and verify novel and existing molecular models of network elasticity and fracture. A novel theory of network fracture that accounts for loop defects by drawing on recent advances in network elasticity is proposed. This loop modified Lake-Thomas Theory is tested against both MD simulations and experimental fracture measurements on model gels. Good agreement between the theory and measurement is obtained. These findings enable a priori estimation of fracture energy in swollen gels where chain scission becomes an important failure mechanism.