Oxygen-Tolerant ATRP Depolymerization Enabled by an External Radical Source

Area of Science:

• Polymer Chemistry
• Sustainable Materials
• Chemical Recycling

Background:

• Chemical recycling of polymers via controlled radical polymerization typically requires strictly anaerobic conditions.
• Existing oxygen-tolerant depolymerization methods are often limited by the need for boiling co-solvents, closed vessels, or result in low monomer recovery.

Purpose of the Study:

• To develop an efficient, open-vessel, oxygen-tolerant depolymerization method for polymers synthesized via atom transfer radical polymerization (ATRP).
• To achieve high monomer regeneration percentages compatible with various solvents and ligands.

Main Methods:

• Depolymerization of ATRP-synthesized polymers in an open-vessel system under oxygen-tolerant conditions.
• Oxygen removal strategies included high catalyst loadings or lower catalyst loadings with a radical initiator.
• Compatibility testing with various solvents (anisole, TCB, DCB) and ligands (Me6TREN, TPMA, TREN, PMDETA).

Main Results:

• Achieved high monomer regeneration efficiency (>90% depolymerization).
• Demonstrated successful depolymerization in the presence of dissolved oxygen without specialized equipment.
• Confirmed compatibility with a wide range of common solvents and ligands, including cost-effective alternatives.

Conclusions:

• The developed method offers a practical and efficient approach for the chemical recycling of ATRP polymers.
• This advancement overcomes the limitations of anaerobic conditions and expands the scope of recyclable polymers.
• The compatibility with diverse solvents and ligands enhances the method's applicability and economic viability.