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Mechanical Modeling of the Strain‐Induced‐Crystallization in Polymers
Author(s) -
Aygün Serhat,
Klinge Sandra
Publication year - 2017
Publication title -
pamm
Language(s) - English
Resource type - Journals
ISSN - 1617-7061
DOI - 10.1002/pamm.201710164
Subject(s) - crystallization , nucleation , helmholtz free energy , polymer , dissipation , materials science , work (physics) , natural rubber , crystallization of polymers , strain (injury) , thermodynamics , composite material , physics , medicine
The strain‐induced crystallization (SIC) in polymers is a phenomenon manifesting itself as the natural reinforcement caused by the high deformation or by the reduction of the temperature. It is typical for natural rubber, since this material contains more regularly oriented chains than the other polymers. Most of the models focusing on the modeling of polymers use the Langevin expression for the free energy as a basis [1]. The current work, however, treats a polymer affected by the strain induced crystallization as a heterogeneous medium consisting of regions with a different degree of network regularity. Such a concept allows the depiction of the nucleation and the growth of crystalline regions as well as the change of effective material parameters depending on the level of the strain applied. The model proposed is thermodynamically consistent. It is based on the assumptions for the free Helmholtz energy and dissipation potential. The inelastic deformations and degree of the network regularity are internal variables. Their evolution equations are derived according to the minimum principle of the dissipation potential. (© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)