Page 77 - Plastics News July 2025
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PRODUCT NEWS
Optimizing Thermoset Epoxies
for Additive Manufacturing with Sparse Infill
The figure illustrates: (a) Montmorillonite-sepi-
olite agglomerates, with surface fibrils from se-
piolite measuring approximately 5 μm in length;
(b) Micronized amide particles characterized by
a rounded shape and a wide range of particle
sizes, with a reported D50 of less than 14 μm;
and (c) Carbon nanotubes clustered into fibrous
bundles, resembling a woven textile. Courtesy
of Novel Thermoset Formulations for Additive
Manufacturing of Structures with Sparse Infill.
ichigan State University researchers Thermoset resins, often referred to as “inks,”
unveiled novel thermoset epoxies ca- require rheology-modifying additives to achieve
Mpable of bridging unsupported gaps in yield stress behavior and strong shear thinning.
sparse infill structures at ANTEC 2025. In this study, researchers used Diglycidyl Ether
of Bisphenol-A (DGEBA) as the resin base and
Sparse infill structures offer significant advan-
tages in weight reduction and time savings. tested three additives: montmorillonite-sepiolite
However, fully realizing these benefits requires clay, micronized amide, and carbon nanotubes
materials that can effectively bridge unsupport- (CNTs).
ed gaps. Therefore, Mitchell Delemeester and The team first evaluated clay and micronized
Krishnamurthy Jayaraman conducted a study amide individually. Clay offered good elastic-
showcasing new thermoset resins for extru- ity and some sag resistance but showed poor
sion deposition additive manufacturing (EDAM). pumpability due to high viscosity at low shear
These materials exhibit enhanced rheological rates. In contrast, micronized amide provided
properties, significantly improving sag resist- moderate sag resistance and strong thixotropy,
ance in sparse infill structures. allowing the resin to flow under stress and re-
cover. Despite these advantages, its yield stress
Discovering Novel Formulations
(~550 Pa) was insufficient for large unsupported
spans. Additionally, after heating, the structure
weakened during extrusion, temporarily reduc-
ing mechanical strength.
Building on these findings, researchers decided
July 2025 PLASTICS NEWS 77
