Influence of micro injection moulding process parameters on mechanical characteristics of POM and POM/CNT composites

Micro injection moulding is one of the most used thermoplastic technology for the manufacturing of miniaturized products, due to the high productivity of the process. Thermoplastic micro manufacturing has reached nowadays an incredible spread: polymeric components are used in several fields, such as biomedical, IT, telecommunication, automotive and aerospace. In recent years, an innovation in polymer area was the addition of fillers on the pure polymer, in order to improve the physical properties and/or to reduce the cost of the composite. The aim of the present work is to carry out a comparison between the mechanical properties of POM base material and POM filled with carbon nanotubes micro injected using different process parameters - melting temperature, injection speed and holding pressure. Uniaxial mechanical tests were performed to obtain the main mechanical properties: yield stress, deformation at break and stress at break. The results, analyzed with Analysis of Variance statistical approach show that the mechanical response of the micro¬ specimens is mainly affected by the CNT presence, whereas the other factors seems to play only a secondary role. The presence of CNT induces a remarkable increase in the mechanical resistance, but drastically reduces the material ductility.