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

Alberto S De León,Sergio I Molina

doi:10.3390/polym12051103

Abstract

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.

Highlights

Polymer matrix nanocomposites are emerging as cheaper, tougher and lighter materials for a wide variety of applications including energy storage, biomedicine or aerospace and automotive industries [1]
CAD files were loaded into the SLA software and different objects were printed using the nanocomposite precursors containing 0.5–5.0 wt % graphite nanoplatelets (GNPs)
Too viscous resins have limited capacity to flow during this step, which leads to GNPs local accumulation that interferes with the laser path [31]

Summary

Introduction

Polymer matrix nanocomposites are emerging as cheaper, tougher and lighter materials for a wide variety of applications including energy storage, biomedicine or aerospace and automotive industries [1]. They consist of a nanomaterial such as fibers, particles or 2D materials embedded within a polymeric matrix. GNPs have been used in different matrixes at the industrial scale due to their inexpensive cost in a different number of matrixes to increase their stiffness Their elasticity and tensile strength generally decrease due to their poor compatibility with polymeric matrixes. Other authors propose chemical strategies to modify GNPs in order to achieve a better compatibility with the matrix and increase the tensile strength of the material [12,13]

Methods

Results

Conclusion