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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 72: Polymer Networks and Elastomers
CPP 72.6: Vortrag
Mittwoch, 18. März 2020, 16:30–16:45, ZEU 114
Nonlinear mechanics of physically crosslinked elastomers: from molecular simulations to network models — •Joerg Rottler1 and Amanda Parker2 — 1Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada V6T 1Z1 — 2Data 61, CSIRO, Melbourne, Australia
Thermoreversible (physical) crosslinking is a versatile strategy for improving the strength and toughness of elastomers that also permits self-healing upon thermal cycling. There is no universally applicable theory for predicting their mechanical response because the mechanical response is governed by the microscopic polymer chain conformations during deformation that cannot easily be measured experimentally. Here, we present a family of entropic network models that account for the stress contributions arising from chain crosslinks as well as entanglements by coupling analytical expressions for the strain energy density directly with chain deformations obtained through molecular dynamics simulations. Our theory quantitatively reproduces the macroscopic stress response of simulated linear and star block copolymer elastomers well into the nonlinear regime. The simulations reveal the evolution of entanglements and how the breakup of physical crosslinks contributes to additional strain hardening. Although developed for a classic sphere forming ABA block copolymer system, our approach can readily be applied to any (bio)macromolecular network in which a rigid phase anchors polymer chains otherwise forming a rubbery matrix.