Self Assembly–Assisted Additive Manufacturing: Direct Ink Write 3D Printing of Epoxy–Amine Thermosets

Abstract

The use of self‐assembling, pre‐polymer materials in 3D printing is rare, due to difficulties of facilitating printing with low molecular weight species and preserving their reactivity and/or functions on the macroscale. Akin to 3D printing of small molecules, examples of extrusion‐based printing of pre‐polymer thermosets are uncommon, arising from their limited rheological tuneability and slow reactions kinetics. The direct ink write (DIW) 3D printing of a two‐part resin, Epon 828 and Jeffamine D230, using a self‐assembly approach is reported. Through the addition of self‐assembling, ureidopyrimidinone‐modified Jeffamine D230 and nanoclay filler, suitable viscoelastic properties are obtained, enabling 3D printing of the epoxy–amine pre‐polymer resin. A significant increase in viscosity is observed, with an infinite shear rate viscosity of approximately two orders of magnitude higher than control resins, in addition to, an increase in yield strength and thixotropic behavior. Printing of simple geometries is demonstrated with parts showing excellent interlayer adhesion, unachievable using control resins.

Development and Characterization of Stable Polymer Formulations for Manufacturing Magnetic Composites

“…This rheological additive is known to create a 3D network through hydrogen bonding with epoxy polymer chains resulting in a gel-like structure. Epoxy resins containing the rheological additive exhibit shear thinning behavior through the disruption of the network structure, while the formation of hydrogen bonds imparts thixotropic properties, enabling time-dependent changes in viscosity [31]. Comparing flow behavior of samples NdFeB-a5EPX and NdFeB-a10EPX, it can be concluded that an increase in rheological additive content fostered strong shear thinning behavior, which is supported by a low flow index value.…”

Recent Progress on Polymer Materials for Additive Manufacturing

“…[297] The thixotropic behavior of the inks can be tailored through the interactions between their molecules or particles, which can be temporarily disrupted by a mechanical stimulus (i.e., shear force during the ink deposition process) and then reinstated upon deposition. [297,298]…”

3D Printing for the Clinic: Examining Contemporary Polymeric Biomaterials and Their Clinical Utility

“…The part maintains its shape during printing as a consequence of the rheological properties of the ink while the cross-linking takes place. 20 Ideally, DIW materials are able to maintain their shape provided that no external shear is applied; only during the extrusion process itself is the material able to flow. 11 The major advantage of DIW in polymers relies on the highly precise print features (below 100 μm) that are possible as a result of the use of automated print heads coupled with small diameter nozzles which control material flow, as well as the wide array of compatible materials that can be used, which include thermoplastic polymers and composites, thermosetting materials, hydrogels, graphene, ceramics, and even metals in specialized cases.…”