(494d) Role of Topological Defects on Fracture of Polymer Networks

Chemically crosslinked polymer networks often possess various types of topological defects such as loops and bridges, which are shown to have a noticeable effect on elastic properties of the material. In this work, we use theory and simulations to investigate the influence of such defects on the fracture of the material. A Monte Carlo algorithm is first used to generate a series of 3D periodic networks having varying concentration of defects. The respective networks are then subjected to tensile deformation with the bond breaking events modeled using a kinetic theory of fracture incorporating the experimentally-measured mechanochemical characteristics of covalent bonds. We discuss the effect of both the fraction of primary loops and their spatial distribution on the fracture toughness of the material. Additionally, we use the classical Lake-Thomas theory to estimate the ultimate strength of defects-containing networks, and compare the resulting predictions to simulation results. Using both theory and simulations, this work provides insight into the molecular origins of fracture in polymer networks.

This work is supported by Dow.