Living Alternating Ring-Opening Metathesis Polymerization Based on Single Monomer Additions

Area of Science:

• Polymer Chemistry
• Organic Synthesis
• Materials Science

Background:

• Ring-opening metathesis polymerization (ROMP) is a versatile technique for polymer synthesis.
• Achieving controlled living polymerization and alternating copolymerization remains a challenge for certain monomers.

Purpose of the Study:

• To develop novel cyclopropene monomers for controlled ROMP.
• To achieve living alternating ring-opening metathesis polymerization (ROMP) with low-strain cyclic olefins.
• To investigate the kinetic behavior of disubstituted cyclopropenes in polymerization.

Main Methods:

• Synthesis of specifically designed disubstituted cyclopropenes.
• Ring-opening metathesis polymerization (ROMP) with various low-strain cyclic olefins.
• Characterization using NMR spectroscopy (1H and 13C) and MALDI-TOF MS.

Main Results:

• Disubstituted cyclopropenes selectively undergo single monomer addition in ROMP.
• Achieved living alternating ROMP with low-strain cyclic olefins, yielding polymers with controlled molecular weights and low dispersities.
• Demonstrated high microstructural regularity and rigorously alternating sequences in the resulting copolymers.
• Observed zero-order kinetics for disubstituted cyclopropenes, indicating rapid initial addition.

Conclusions:

• Judicious modulation of ring strain and sterics in cyclopropenes is key to controlling ROMP.
• This approach provides a powerful new route for synthesizing well-defined alternating copolymers.
• The developed method offers precise control over polymer architecture and properties.