Photoredox-Initiated Frontal Ring-Opening Metathesis Polymerization

Area of Science:

• Polymer Chemistry
• Organic Chemistry
• Materials Science

Background:

• Ring-opening metathesis polymerization (ROMP) is a versatile method for polymer synthesis.
• Frontal polymerization offers advantages in reaction control and efficiency.
• Developing novel initiation methods for frontal polymerization is crucial for expanding its applications.

Purpose of the Study:

• To develop a photoredox-initiated chemical system for frontal ring-opening metathesis polymerization (FROMP).
• To investigate the kinetics and thermal behavior of the photoredox-initiated FROMP.
• To evaluate the properties of polymers synthesized using this new system.

Main Methods:

• Utilized a ruthenium-based bis-N-heterocyclic carbene metathesis precatalyst.
• Employed 9-mesityl-10-phenylacridindium tetrafluoroborate and copper(II) triflate as activators.
• Initiated polymerization using a 455 nm light source for dicyclopentadiene monomer.

Main Results:

• Successfully initiated FROMP using a photoredox system.
• Achieved controlled reaction fronts with speeds ranging from 0.15 to 0.43 mm s⁻¹.
• Observed front temperatures between 140 °C and 205 °C.
• Synthesized polymers with lower glass transition temperatures compared to Grubbs' catalyst but with extended pot life.

Conclusions:

• The photoredox-initiated FROMP system offers a novel route for controlled polymer synthesis.
• This method provides a balance between reaction control and extended usability.
• The developed system demonstrates potential for advanced polymer manufacturing.