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Photogeneration of N-Heterocyclic Carbenes: Application in Photoinduced Ring-Opening Metathesis Polymerization
Published on: November 29, 2018
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Exploring Aromatic S-Thioformates as Photoinitiators.
Paul Rieger1, Sabrina Pueschmann2, Michael Haas2
1Institute of Chemistry of Polymeric Materials, Montanuniversität Leoben, Otto Glöckelstrasse 2, 8700 Leoben, Austria.
Polymers
|April 13, 2023
Summary
New photoinitiators (PIs) derived from aromatic S-thioformates enable efficient polymerization. These PIs offer stable reactivity and high-resolution 3D printing via digital light processing (DLP) stereolithography.
Area of Science:
- Polymer Chemistry
- Photochemistry
- Materials Science
Background:
- Aromatic thiols are commonly used in photopolymerization but can undergo undesired side reactions.
- Developing stable and efficient photoinitiators (PIs) is crucial for advanced resin systems.
Purpose of the Study:
- To synthesize and evaluate aromatic S-thioformates as novel photoinitiators for polymerization.
- To demonstrate their utility in acrylate-based resin systems and 3D printing applications.
Main Methods:
- Thiyl radicals were generated from aromatic S-thioformates via photolysis.
- Photo-initiated decarbonylation was used to initiate polymerization in acrylate and thiol-acrylate systems.
- A bifunctional S-thioformate, S,S'-(thiobis(4,1-phenylene))dimethanethioate (2b), was synthesized and tested.
Main Results:
- Aromatic S-thioformates effectively initiated polymerization through photo-initiated decarbonylation.
- The photolabile formyl group prevented premature reactions with acrylate monomers, ensuring storage stability.
- The synthesized bifunctional S-thioformate (2b) demonstrated reactivity under visible light (405 nm).
- High-resolution digital light processing (DLP)-based stereolithography was achieved using acrylate formulations with these PIs.
Conclusions:
- Aromatic S-thioformates are promising photoinitiators offering enhanced stability and controlled reactivity.
- These novel PIs facilitate efficient photopolymerization and high-resolution 3D printing applications.
- The developed S-thioformate system represents an advancement in photopolymerization technology for stereolithography.
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