Characterization of polymer architecture: Modeling and experiment


We use a coarse-grained slip-link model to investigate the rheology of polydisperse linear and star-shaped polymer melts. Our slip-link model is a well-defined mathematical object that can describe the equilibrium dynamics and non-linear rheology of flexible polymer melts with arbitrary polydispersity and architecture with a minimum of inputs: the molecular weight of a Kuhn step, the entanglement activity and the Kuhn step shuffling time. The model takes into account the explicit creation and destruction of entanglements along polymer backbones in a stochastic way derived from a master equation. The computational implementation of this model is accelerated with the help of graphics processing units, which allow us to simulate in parallel large ensembles made of up to 50000 chains with variable number of entanglements. We report the storage and loss moduli for polymer melts with different molecular weight and polydispersity. Also we compare our predictions with experimental results obtained from small amplitude oscillatory shear, for polybutadiene, polypropylene and polyethylene melts. We show that our simulation can predict the dynamic moduli for highly entangled polymer melts over nine decades.

Denver, Colorado