Toward Fully Controllable Monomers Sequence: Binary Organocatalyzed Polymerization from Epoxide/Aziridine/Cyclic...

Area of Science:

• Polymer Chemistry
• Catalysis
• Materials Science

Background:

• Monomer sequence critically influences polymer properties.
• Controlling monomer arrangement during copolymerization is challenging.
• Catalyst manipulation is key to precise sequence control.

Purpose of the Study:

• To report catalyst-controlled copolymerization of epoxides, N-tosyl aziridine (TAz), and cyclic anhydrides.
• To demonstrate continuous modulation of polymer sequence using a binary catalyst system.
• To explore the relationship between monomer sequence and polymer properties.

Main Methods:

• Utilized a binary catalyst system: Lewis acid (triethylborane) and Brønsted base (t-BuP1).
• Regulated selectivity between ring-opening alternating copolymerization (ROAC) pathways.
• Employed varying catalyst ratios to control monomer sequence.
• Conducted density functional theory (DFT) calculations for mechanistic insights.

Main Results:

• Achieved continuous modulation of poly(ester-amide ester) from ABA-type block to gradient, random-like, reversed gradient, and reversed BAB-type block-like copolymers.
• Demonstrated versatility with a range of epoxides and anhydrides.
• Established a method for producing copolymers with tunable sequences.

Conclusions:

• The binary catalyst system offers precise control over monomer sequencing in copolymerization.
• This method enables the synthesis of diverse polymer architectures.
• Provides valuable insights into structure-property relationships for polymer advancement.