On the Mechanical Response of Silicon Dioxide Nanofiller Concentration on Fused Filament Fabrication 3D Printed Isotactic Polypropylene Nanocomposites

Nectarios Vidakis; Markos Petousis; Emmanouil Velidakis; Lazaros Tzounis; Nikolaos Mountakis; Apostolos Korlos; Peder Erik Fischer-Griffiths; Sotirios Grammatikos

doi:10.3390/polym13122029

On the Mechanical Response of Silicon Dioxide Nanofiller Concentration on Fused Filament Fabrication 3D Printed Isotactic Polypropylene Nanocomposites

Polymers (Basel). 2021 Jun 21;13(12):2029. doi: 10.3390/polym13122029.

Authors

Nectarios Vidakis¹, Markos Petousis¹, Emmanouil Velidakis¹, Lazaros Tzounis², Nikolaos Mountakis¹, Apostolos Korlos³, Peder Erik Fischer-Griffiths⁴, Sotirios Grammatikos⁴

Affiliations

¹ Mechanical Engineering Department, Hellenic Mediterranean University, 71410 Heraklion, Greece.
² Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina, Greece.
³ Department of Industrial Engineering and Management, International Hellenic University, 14th Km Thessaloniki-N. Moudania, Thermi, 57001 Thessaloniki, Greece.
⁴ Laboratory of Advanced and Sustainable Engineering Materials (ASEMlab), Department of Manufacturing & Civil Engineering, NTNU-Norwegian University of Science and Technology, Building B' Teknologivegen 22, 2815 Gjøvik, Norway.

Abstract

Utilization of advanced engineering thermoplastic materials in fused filament fabrication (FFF) 3D printing process is critical in expanding additive manufacturing (AM) applications. Polypropylene (PP) is a widely used thermoplastic material, while silicon dioxide (SiO₂) nanoparticles (NPs), which can be found in many living organisms, are commonly employed as fillers in polymers to improve their mechanical properties and processability. In this work, PP/SiO₂ nanocomposite filaments at various concentrations were developed following a melt mixing extrusion process, and used for FFF 3D printing of specimens' characterization according to international standards. Tensile, flexural, impact, microhardness, and dynamic mechanical analysis (DMA) tests were conducted to determine the effect of the nanofiller loading on the mechanical and viscoelastic properties of the polymer matrix. Scanning electron microscopy (SEM), Raman spectroscopy and atomic force microscopy (AFM) were performed for microstructural analysis, and finally melt flow index (MFI) tests were conducted to assess the melt rheological properties. An improvement in the mechanical performance was observed for silica loading up to 2.0 wt.%, while 4.0 wt.% was a potential threshold revealing processability challenges. Overall, PP/SiO₂ nanocomposites could be ideal candidates for advanced 3D printing engineering applications towards structural plastic components with enhanced mechanical performance.

Keywords: Charpy impact test; Vickers microhardness; additive manufacturing (AM); flexural test; nanocomposites; polypropylene (PP); scanning electron microscopy (SEM); silicon dioxide (SiO2); tensile test; three-dimensional (3D) printing.