Recyclable Crosslinked Semicrystaline Photopolymers

Commercial photoresins predominantly rely on (meth)acrylate-based formulations, which offer fast gelation rates, tunable crosslink densities/material properties, and relatively cost-effective production. Their popularity and demand is evidenced by the 27,000 metric tons of photoresins that were produced, globally, in 2023. Unfortunately, (meth)acrylate -based systems suffer from oxygen inhibition during curing and high shrinkage stress after curing. Thiol-ene click chemistry has emerged as a promising alternative to photopolymerization because of oxygen tolerance and high conversion efficiency. However, these photoresins are permanently crosslinked network structures, prohibiting their reprocessing/recycling and posing a significant material sustainability challenge due to their end-of-life waste accumulation.

 

Researchers at Arizona State University have developed semicrystalline thiol–ene photopolymers which are synthesized through a scalable one-step thiol–ene click reaction process. Incorporating exchangeable disulfide bonds, these photopolymers offer tunable cross-link density and crystallinity, enabling control over mechanical performance, including Young’s modulus and elongation. They are compatible with Digital Light Processing (DLP) 3D printing techniques, enabling the fabrication of highly detailed and complex geometries with shape memory capabilities. Crucially, the photopolymers can be chemically decross-linked and recycled multiple times via thiol-disulfide exchange reactions without the need for solvents or catalysts, promoting sustainable closed-loop recycling in photopolymer applications.

 

These innovative photopolymers are designed for next generation high-resolution 3D printing with adaptable mechanical properties and closed-loop chemical recyclability.

 

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