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Oxygen Tolerant and Room Temperature RAFT through Alkylborane Initiation
Olivia R Wilson1, Andrew J D Magenau1
1Department of Materials Science and Engineering, Drexel University, Philadelphia, Pennsylvania 19104, United States.
ACS Macro Letters
|May 28, 2022
Summary
Researchers developed air-stable alkylborane-initiated reversible addition-fragmentation chain transfer (AI-RAFT) polymerization. This method enables rapid polymer synthesis at room temperature, even with oxygen present, without special stimuli.
Area of Science:
- Polymer Chemistry
- Organic Synthesis
Background:
- Reversible Addition-Fragmentation chain Transfer (RAFT) polymerization is a controlled radical polymerization technique.
- Traditional RAFT often requires stringent conditions, such as inert atmospheres and specific initiators, limiting its practical application.
Purpose of the Study:
- To develop a novel, air-stable RAFT process initiated by alkylborane-amine complexes.
- To enable rapid polymerization at room temperature in the presence of oxygen.
Main Methods:
- Utilized an air-stable alkylborane-amine complex that, upon chemical deblocking with carboxylic acids or isocyanates, generates oxygen-scavenging radicals.
- Initiated RAFT polymerization using the in-situ generated radicals, termed AI-RAFT.
- Investigated optimal deblocker stoichiometry and functionality for controlled polymerization.
Main Results:
- Demonstrated AI-RAFT's capability to synthesize polymers with controlled molecular weights and narrow molecular weight distributions.
- Achieved rapid polymerization within minutes under ambient conditions without deoxygenation.
- Confirmed living characteristics by synthesizing block copolymers using AI-RAFT macro-chain transfer agents.
- Successfully polymerized acrylamide, acrylate, and methacrylate monomers.
Conclusions:
- AI-RAFT offers a versatile, chemically induced polymerization method that bypasses the need for thermal, photochemical, electrical, or mechanical stimuli.
- This approach significantly broadens the scope of RAFT polymerization, allowing for facile synthesis under ambient conditions.
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