Influence of the Degree of Cure in the Bulk Properties of Graphite Nanoplatelets Nanocomposites Printed via Stereolithography

• Published in: Polymers Vol. 12; no. 5; p. 1103
• Main Authors: León, Alberto S de, Molina, Sergio I
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI 12.05.2020; MDPI AG
• Subjects: 3D printing; correlation of bulk and molecular properties; mechanical properties; nanocomposites; physical methods of analysis; stereolithography; correlation of bulk and molecular properties; electrical properties; stereolithography; physical methods of analysis; nanocomposites; 3D printing; mechanical properties
• ISSN: 2073-4360; 2073-4360
• DOI: 10.3390/POLYM12051103

In this work, we report on the fabrication via stereolithography (SLA) of acrylic-based nanocomposites using graphite nanoplatelets (GNPs) as an additive. GNPs are able to absorb UV-Vis radiation, thus blocking partial or totally the light path of the SLA laser. Based on this, we identified a range of GNP concentrations below 2.5 wt %, where nanocomposites can be successfully printed. We show that, even though GNP is well-dispersed along the polymeric matrix, nanocomposites presented lower degrees of cure and therefore worse mechanical properties when compared with pristine resin. However, a post-processing at 60 °C with UV light for 1 h eliminates this difference in the degree of cure, reaching values above 90% in all cases. In these conditions, the tensile strength is enhanced for 0.5 wt % GNP nanocomposites, while the stiffness is increased for 0.5-1.0 wt % GNP nanocomposites. Finally, we also demonstrate that 2.5 wt % GNP nanocomposites possess characteristic properties of semiconductors, which allows them to be used as electrostatic dispersion materials.