Threshold fracture of lightly crosslinked networks

Preparation and characterization of a biodegradable hydrogel containing oligo(2,2-dimethyltrimethylene carbonate) moieties with tunable properties

“…18 Deformation and fracture of the hydrogels under stress can be regarded as the process of absorbing and dissipating energy through the polymer chains. 41,42 The flexible polymer chains adopt random coil conformation before applying stress, and the polymer chains ruptured by Lake-Thomas mechanism after the chains become fully extended and store enough energy (fracture energy) till fracture under stress. 43,44 Compared to the energy needed for fully extending the polymer chain, fracture energy contributes to the dominant term in total energy.…”

Fracture of model polyurethane elastomeric networks

“…Introducing the molecular structure of elastomer chains leads to a prediction:17 where U CC is the molar energy of a CC bond (≈350 kJ mol −1 ), M 0 the monomer molar mass, a the length of monomer (≈5 Å) and ρ the polymer density. This theoretical prediction was tested experimentally and proved to be generally correct 15, 18–21. However, it only applied to the threshold values measurable at high temperature and/or with solvent swollen rubbers, which reduce greatly or avoid completely any viscoelastic dissipation during deformation.…”

Mechanical Behavior of Polymers

“…Two major mechanisms prevail in determining the fracture resistance of polymeric materials (95). One primary contribution comes from the energy required to extend polymer chains, or some subsection thereof to the point of rupture.…”