Effect of network structure on fracture of swollen polymer networks

Mechanical properties of swollen polymer networks depend on the topology of the crosslinked polymer network.

We study the molecular network structure of such polymer networks using coarse-grained molecular dynamics simulations based on Kremer-Grest parametrization. We focus on trapped topological entanglements in these network structures and relate them to the fracture properties of the polymer network.

We model the crosslinking process with end-linked polymer chains to study the effect of synthesis parameters such as solvent concentration and polymer chain length on the structure of crosslinked network.

Our model reveals the effect of polymer chain length on the topology of the polymer network through characterization of topological entanglement length. Increasing the polymer chain length increases the number of entanglements per chain and shows increased fatigue threshold.

Using the topological analysis tools we explain the molecular picture of this enhancement in fatigue threshold in entangled swollen polymer networks for long polymer lengths.