This document describes research into designing ceramic/polymer composites suitable for 3D printing. Semi-crystalline polymers like polyethylene-co-vinyl acetate (PEcVA) and polyethylene oxide (PEO) were found to provide a suitable binder when blended with stearic acid and 60% silica by weight. Composites made from PEO, stearic acid and silica were extrudable but friable. Thermal analysis found the acceptable extrusion range was 120-180°C for PEcVA composites and 100-180°C for PEO composites, but PEO filaments broke during extrusion due to fragility. The research aims to 3D print and fire prototypes

1. Design and Preparation of Ceramic/Polymer Composites for 3D Printing
Megan Detwiler*+, Bria Cherebin*°, Thomas Smith+, Denis Cormier°
School of Chemistry and Materials Science, Rochester Institute of Technology, 14623
Abstract
Three-dimensional (3D) printing is an additive manufacturing technique that
allows for the layer by layer fabrication of complex objects. In the present
research, ceramic/polymer composites suitable for 3D printing have been
designed. A material with a particle size of ̴10nm is desirable, however,
materials that can be extruded into rods or filaments in an extrusion plastometer
are also of interest. It has been found that semi-crystalline polymers with a high
ratio of oxygen to carbon atoms blended with stearic acid can provide a suitable
binder to facilitate the consolidation of initially printed objects. Two promising
semi-crystalline polymers in which 60% by weight silica is incorporated, are
polyethylene-co-vinyl-acetate (PEcVA) and polyethylene oxide (PEO). These
composite materials have been found to be fusible (extrudable). Those made
with PEO and stearic acid were also friable. Thermal properties of these new
composites (DSC, TGA, etc.) have been evaluated.
* Presenting Authors
+ R.I.T. School of Chemistry and Material Science
° R.I.T. Kate Gleason College of Engineering
Acknowledgements
Funded by RIT AMPrint Center
Thomas Allston
Scott Williams
Silica added to the
blender to make a
homogeneous solution
Extruded
Resin kettle
solvent removal
Powdered and
made pellets
Polymer and stearic
acid were dissolved
into MEK in a warring
blender
Fabrication Process
Stearic acid
Polyethylene oxide
Polyethylene-co-vinyl acetate
Film cast for
solvent removal
Scraped and
powdered if possible
Fused between
glass slides
+
Extruded filament
70% silica coated with a mixture of 75:25 PEO to stearic acid​
Extruded filament
Thermal Analysis
Conclusion
DSC of 70% silica PEcVA composite TGA of 70% silica PEcVA composite
DSC of 70% silica PEO composite TGA of 70% silica PEO composite
Stearic acid
+
+
Future Direction
It is anticipated that these materials will be printed, sintered, and fired to
create prototype 3D printed ceramic objects. Additionally, a ring opening
polymerization of α-hydroxyisobutiric acid anhydrosulfite will be
completed in an attempt to increase the weight percentage of ceramic in a
composite ink.
It has been demonstrated that semi-crystilline polymers with a high
oxygen content are viable options for use in 3D printing composites.
The addition of stearic acid is necessary to provide lubrication in
composites with high ceramic content. Thermal analysis of the
fabricated composites shows that the acceptable range for extrusion
of the PEcVA-based ink is 120°C to 180°C. The range for the PEO-
based ink is 100°C to 180°C; however, the PEO filament continuously
broke as it was being extruded. Due to its fragility, it does not have
the strength to be a viable candidate for extrusion.
Composite Compositions
70% silica coated with a
mixture of 50:50 PEcVA to
stearic acid