  The present contribution deals with the thermomechanical modeling of the
strain-induced crystallization in unfilled polymers. This phenomenon
significantly influences mechanical and thermal properties of polymers and has
to be taken into consideration when planning manufacturing processes as well as
applications of the final product. In order to simultaneously capture both
kinds of effects, the model proposed starts by introducing a triple
decomposition of the deformation gradient and furthermore uses thermodynamic
framework for material modeling based on the Coleman--Noll procedure and
minimum principle of the dissipation potential, which requires suitable
assumptions for the Helmholtz free energy and the dissipation potential. The
chosen setup yields evolution equations which are able to simulate the
formation and the degradation of crystalline regions accompanied by the
temperature change during a cyclic tensile test. The boundary value problem
corresponding to the described process includes the balance of linear momentum
and balance of energy and serves as a basis for the numerical implementation
within an FEM code. The~paper closes with the numerical examples showing the
microstructure evolution and temperature distribution for different material
samples.
