Multiscale modelling of layered-silicate/PET nanocomposites during solid-state processing

This work aims to develop a continuum, multi-scale, physically-based model of the forming process for layered-silicate nanocomposites based on poly(ethylene terephthalate) (PET) matrices, as might be used for packaging. This challenge is tackled using: (1) a physically-based model of PET implemented into the FEM-based code ABAQUS, (2) RVEs with prescribed morphologies reflecting TEM images, and (3) nonlinear computational homogenisation. As a result, 2-D two-scale FEM-based simulations under biaxial deformations (constant width) enabled the extraction of macroscopic stress-strain curves at different silicate contents and processing temperatures. In particular, interesting features in terms of morphology changes and its impact on the macroscopic stress response were captured: (a) morphology change by particle re-orientation and pronounced bending, (b) macroscopic strain hardening due to platelet re-orientation and local strain stiffening, (c) facilitated platelet alignment, and platelet delamination in tactoids through sheardominated deformations and increasing temperature.