Simulation of Inelastic Stress - Strain Response of Nanocomposites by a Network Model

Abstract

This paper describes the viscoelastic properties of network model. In the first approximation, nanocomposite was modeled as a 3D tetrafunctional network considering entanglements to act as the physical x-links. Nano-sized non-deformable domains of defined shape and size were introduced into the network. The chains in the vicinity of the inclusions were considered immobilized. Hence, the semicrystalline polymer was considered a three-phase system containing flexible matrix bulk phase, immobilized chains near the inclusion surface and rigid crystalline domains. The crystallites were characterized by their Young's modulus and their traction properties were calculated using the Hooke's law. Unlike the model, the real polymer has viscoelastic deformation properties. The components which could cause viscoelastic properties were introduced and their impact on viscoelastic properties of whole network was investigated. The components were for example the reptation motion of chain in entanglements or chain, whose motion was retarded by impact of surroundings. The model enabled to investigate the influence of each component, as well as the influence of distribution of each component. The types of nods, whose influence was investigated in this contribution, were fast knot, free entanglement, one-way entanglement and energy barrier.