This PhD work is carried out at the Processes and Engineering in Mechanics and Materials laboratory (PIMM) in collaboration with the Centre of Molecular and Macromolecular Studies (CMMS), Łódź, Poland and is dealing with the processing of nanocomposite. CMMS developed a promising nanofibrillation processing route based on the plastic deformation of crystalline disentangled polymers. In order to further our understanding of the phenomena taking place during the process we resort to computational modelling. Due to the very large deformations involved, the Constrained Natural Element Method (CNEM) is used to simulate the nanofibrillation process.