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Abstract 4D printing technology enables the fabrication of constructs capable of shape transformation when exposed to external stimuli. Epoxy‐based shape memory polymers (SMPs) have shown great potential for various 4D printing applications. However, due to their thermocurable nature, the fabrication of 4D constructs using epoxy‐based materials is often limited to a mold casting strategy, limiting design flexibility and often yielding flat structures. In this work, photocurable smart 4D inks are developed by integrating polyethylene glycol diacrylate (PD) into epoxy‐based materials. These inks undergo a two‐step crosslinking process: i) photocuring of the PD network, and ii) thermocuring of the SMP, resulting in an interpenetrating polymer network (IPN). The inclusion of PD in the 4D inks not only enables the formation of complex shapes via the restructuring step but also allows for fine‐tuning of mechanical properties and thermal responsiveness. Additionally, these inks offered greater versatility in employable fabrication techniques, including mold casting, photolithography, and stereolithography (SLA).
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Polyester networks from structurally similar monomers: recyclable-by-design and upcyclable to photopolymers
Epoxy-based polymer networks from step-growth polymerizations are ubiquitous in coatings, adhesives, and as matrices in composite materials. Dynamic covalent bonds in the network allow its degradation into small molecules and thus, enable chemical recycling; however, such degradation often requires elevated temperatures and costly chemicals, resulting in various small molecules. Here, we design crosslinked polyesters from structurally similar epoxy and anhydride monomers derived from phthalic acid. We achieve selective degradation of the polyesters through transesterification reactions at near-ambient conditions using an alkali carbonate catalyst, resulting in a singular phthalic ester. We also demonstrate upcycling the network polyesters to photopolymers by one-step depolymerization using a functional alcohol.
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- Award ID(s):
- 1950589
- PAR ID:
- 10432208
- Date Published:
- Journal Name:
- Polymer Chemistry
- Volume:
- 14
- Issue:
- 25
- ISSN:
- 1759-9954
- Page Range / eLocation ID:
- 2964 to 2970
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/D3PY00338H
