Nanocomposite thermoplastic polymer sheets for medical applications: influence of processing conditions on material properties
01.01.2007 - 01.01.2012
This project was performed in collaboration with Orfit Industries, a company developing and producing thermoplastic sheets for immobilization purposes in the field of physical rehabilitation and radiation oncology. The aim of this study was to reduce the sheet thickness without having to compromise on mechanical performance. To achieve this objective nanocomposite polymeric materials were made via twin-screw extrusion, exploring a wide range of nanofillers.
For each thermoplastic nanocomposite mechanical properties were investigated and linked to morphology, which are largely influenced by the dispersion of the selected nanofiller (assessed via electron microscopy, scattering techniques and advanced thermal analysis). The dispersion quality depends on the molecular characteristics of the materials used, but it is also governed by the extrusion conditions, like screw speed or screw design. Therefore, the extrusion conditions needed to be optimized for each nanocomposite, both experimentally and via modelling.
The influence of the nanofiller on the polymer crystallization kinetics is of prime importance, since the solidification process during application by cooling down the thermoplastic polymer sheets will be influenced. During application, the molten material is stretched and moulded on the patient’s body part that needs to be immobilized. When cooling down the material starts to crystallize and consequently shrinks onto the patient . Therefore, the influence of the nanofiller on the entire crystallization process during application was investigated and modelled.