Design and direct fabrication of high‐performance thermosets and composites via 3D printing are highly desirable in engineering applications. Most 3D printed thermosetting polymers to date suffer from poor mechanical properties and low printing speed. Here, a novel ink for high‐speed 3D printing of high‐performance epoxy thermosets via a two‐stage curing approach is presented. The ink containing photocurable resin and thermally curable epoxy resin is used for the digital light processing (DLP) 3D printing. After printing, the part is thermally cured at elevated temperature to yield an interpenetrating polymer network epoxy composite, whose mechanical properties are comparable to engineering epoxy. The printing speed is accelerated by the continuous liquid interface production assisted DLP 3D printing method, achieving a printing speed as high as 216 mm h−1. It is also demonstrated that 3D printing structural electronics can be achieved by combining the 3D printed epoxy composites with infilled silver ink in the hollow channels. The new 3D printing method via two‐stage curing combines the attributes of outstanding printing speed, high resolution, low volume shrinkage, and excellent mechanical properties, and provides a new avenue to fabricate 3D thermosetting composites with excellent mechanical properties and high efficiency toward high‐performance and functional applications.
3D printing of polymers is accomplished easily with thermoplastics as the extruded hot melt solidifies rapidly during the printing process. Printing with liquid polymer precursors is more challenging due to their longer curing times. One curable liquid polymer of specific interest is polydimethylsiloxane (PDMS). This study demonstrates a new efficient technique for 3D printing with PDMS by using a capillary suspension ink containing PDMS in the form of both precured microbeads and uncured liquid precursor, dispersed in water as continuous medium. The PDMS microbeads are held together in thixotropic granular paste by capillary attraction induced by the liquid precursor. These capillary suspensions possess high storage moduli and yield stresses that are needed for direct ink writing. They could be 3D printed and cured both in air and under water. The resulting PDMS structures are remarkably elastic, flexible, and extensible. As the ink is made of porous, biocompatible silicone that can be printed directly inside aqueous medium, it can be used in 3D printed biomedical products, or in applications such as direct printing of bioscaffolds on live tissue. This study demonstrates a number of examples using the high softness, elasticity, and resilience of these 3D printed structures.
more » « less- PAR ID:
- 10036377
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials
- Volume:
- 29
- Issue:
- 30
- ISSN:
- 0935-9648
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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