Enabling Controlled Synthesis of Poly(1,3-dioxolane) by Anion-Binding Catalytic Cationic Ring-Opening Polymerization

Area of Science:

• Polymer Chemistry
• Materials Science
• Organic Synthesis

Background:

• Poly(1,3-dioxolane) (PDXL) is a promising thermoplastic with potential for chemical recycling.
• Commercial application of PDXL is limited by challenges in controlling molecular weight and chain-end fidelity during synthesis.
• Existing synthetic methods often struggle to achieve precise control over PDXL polymer architecture.

Purpose of the Study:

• To develop a controlled cationic ring-opening polymerization (CROP) strategy for Poly(1,3-dioxolane) (PDXL).
• To enable precise control over molecular weights and achieve high chain-end fidelity in PDXL synthesis.
• To explore the use of anion-binding catalysis for reversible-deactivation CROP.

Main Methods:

• Utilized a selenocyclodiphosph(V)azane catalyst for anion-binding catalysis.
• Employed Me3SiX (X = I or OTf) initiators for initiating polymerization and masking chain ends.
• Implemented counteranion engineering to modulate cationic species concentration and control polymerization outcomes.
• Applied quenching strategies to convert masked chain ends to hydroxyl groups, ensuring telechelic fidelity.

Main Results:

• Achieved controlled synthesis of Poly(1,3-dioxolane) (PDXL) under mild conditions via anion-binding catalytic CROP.
• Demonstrated precise synthesis of low-molecular-weight (4.2-24.4 kDa) α,ω-dihydroxy telechelic PDXL using iodide as the counteranion.
• Successfully synthesized high-molecular-weight (up to 562.0 kDa) PDXL using triflate as the counteranion with a proton trap.
• Established a method for on-demand modulation of polymer molecular weight through counteranion selection.

Conclusions:

• The developed anion-binding catalytic CROP strategy offers precise control over PDXL synthesis.
• This approach overcomes previous limitations in controlling molecular weights and chain-end fidelity.
• The ability to synthesize both low and high molecular weight telechelic PDXL opens new avenues for its application in chemically recyclable materials.