DMF/DMSO-catalyzed selective ring-opening polymerization of salicylate cyclic esters.

Area of Science:

• Polymer Chemistry
• Biomaterials Science

Background:

• Salicylate copolyesters offer desirable properties like biodegradability and biocompatibility for biomedical uses.
• Removing toxic catalyst residues is crucial for medical applications but challenging in high-molecular-weight polyester synthesis.

Purpose of the Study:

• To develop a method for synthesizing high-molecular-weight salicylate copolyesters with controlled molecular weights.
• To eliminate toxic catalyst residues from the final polymer products.

Main Methods:

• Utilized dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) as weak hydrogen-bonding catalysts for ring-opening polymerization (ROP) of salicylate cyclic esters.
• Investigated selective cleavage of phenolic ester bonds in monomers over polymer chains.
• Employed theoretical calculations to understand the catalytic mechanism.

Main Results:

• Achieved controlled synthesis of high-molecular-weight salicylate copolyesters (M_n up to 530.0 kg mol^-1) by suppressing side reactions.
• Demonstrated selective ROP of the phenolic ester bond in monomers.
• Showcased catalyst removal via devolatilization and polymerization control in the presence of water.

Conclusions:

• DMF and DMSO efficiently catalyze controllable ROP of salicylate cyclic esters, yielding high-molecular-weight polymers.
• The method eliminates toxic residues and simplifies purification, enhancing suitability for medical applications.
• Weak hydrogen bonding interactions are key to the selective and controlled polymerization mechanism.