Self-standing and Shape-memorable UV-curing Epoxy Polymers for Three Dimensional (3D) Continuous-filament Printing

Document Type

Article

Publication Date

3-7-2018

Publication Title

Journal of Materials Chemistry C

Volume

6

Issue

12

First page number:

2996

Last page number:

3003

Abstract

In the development of three-dimensional printable materials for high-speed and high-resolution printing, UV-curing polymers can guarantee fast and precise printing of high performance load-bearing structures, but the injected drops of the monomers tend to spread over the substrates due to their low viscosity. In this study, we imposed the self-standing and shape-memorable capability of an epoxy acrylate (EA) monomer to ensure continuous filamentary 3D printing while maintaining its low viscosity nature. Using octadecanamide (ODA) with EA, strong hydrogen-bond networks (−N−H⋯O[double bond, length as m-dash]C−, −N−C[double bond, length as m-dash]O⋯H–O–, –N–H⋯N–) were additionally achieved in the material system and the developed material distinctively exhibited rheological duality at different processing stages: a low-viscosity liquid-like behavior (viscosity of ∼50 Pa) while passing through the nozzle and a self-standing solid-like behavior (static yield stress of ∼364 Pa) right after being printed. This reversible liquid-to-solid transitional capability was quantified by viscoelastic complex moduli provided a dynamic yield stress (τy,G) of 210 Pa corresponding to the upright stacking up to ∼3.2 cm (3 wt% of ODA). The time (ty,G) required for conformational rearrangement was evaluated to be as fast as ∼10−2 s. After UV curing, the 3D printed layers exhibited no air pockets or weld lines at the stacked interfaces, which could guarantee excellent mechanical performance and structural integrity.

Keywords

Curing; Hydrogen bonds; Monomers; Phase interfaces; Polymers; Viscosity; Viscosity of liquids; Yield stress

Disciplines

Chemistry

Language

English

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