Molecular Simulations for Entangled Polymer Dynamics

Abstract

A novel method for multi-body molecular simulations for entangled polymers including branch polymers, polymer blends and copolymers is developed in this study. Entangled polymer dynamics is important in industry and still challengeable in polymer science due to complicated rheology caused by a broad variety of controllable polymer architectures such as molecular weight, molecular weight distribution, long chain branching, copolymerization, etc. and freedom of their blends. Conventional molecular simulations are inadequate to the polymer dynamics in long time range because of huge calculation cost. Theoretical approaches based on reptation theories are essentially difficult for multi-component situations due to the self-consistent treatment of entanglement among many chains. In this study a new method of molecular simulations for entangled polymer dynamics is developed based on the primitive chain network model where polymers are considered as primitive chains forming real network in 3D space similarly to the conventional molecular simulations and distinguishably from other entanglement based models. Reasonable consistency on established scaling behaviors for static and dynamic properties and quantitative agreement with experiments for linear and nonlinear rheology have been confirmed for linear and branched polymers. For copolymers and blends reasonable results have been obtained on phase behaviors.