Diffuse interface modelling of the rheology of immiscible polymer blends
Han Meijer, Bert Keestra, Peter Van Puyvelde, Patrick Anderson
Eindhoven University of Technology
Netherlands

Keywords: blends

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The objective of this work is to predict macroscopic properties of polymer
blends, such as the first normal stress difference based on the information
obtained with simulations of morphology development on a microstructural
level. A numerical model, based on a Galerkin spectral element technique, is
applied to study morphology development including the kinetics of phase
separation in a homogeneous shear flow. The theory of Cahn and Hilliard,
describing the free energy of a non-uniform system with local and non-local
gradient terms, is used in the framework of non-classical thermodynamics
described by de Groot and Mazur. Dependent on the shear rate and the
Capillary number different morphologies are found. The results show that the
model can deal with breakup and coalescence without any additional decision
criteria. Moreover, rheological properties of the different blends are
derived and discussed.