Recyclable Organocatalyzed Poly(Thiourethane) Covalent Adaptable Networks

Area of Science:

• Polymer Chemistry
• Materials Science

Background:

• Poly(thiourethane)s (PTUs) are versatile polymers with potential applications in various fields.
• Developing PTUs with enhanced properties, such as recyclability and vitrimer-like behavior, is an active area of research.

Purpose of the Study:

• To synthesize novel networked poly(thiourethane)s using tetraphenylborate salts of highly basic amines.
• To investigate the vitrimer-like behavior and recyclability of the synthesized PTUs.
• To elucidate the mechanism responsible for the observed topological rearrangements.

Main Methods:

• Synthesis of PTUs using hexamethylene diisocyanate (HDI) and trithiol (S3) with tetraphenylborate salts of DBN, DBU, and TBD.
• Characterization using FTIR, thermomechanical analysis, thermogravimetry, stress-relaxation, and tensile tests.
• Evaluation of recyclability through grinding and hot-pressing, followed by comprehensive characterization.

Main Results:

• PTUs synthesized with tetraphenylborate salts exhibited higher stress-relaxation rates compared to those prepared with dibutyltin dilaurate (DBTDL).
• The synthesized PTUs demonstrated excellent recyclability without significant loss of network structure or performance.
• The dissociative interchange trans-thiocarbamoylation mechanism was identified as the primary driver for high-temperature topological rearrangements.

Conclusions:

• Tetraphenylborate salts are effective catalysts for preparing vitrimer-like PTUs with enhanced properties.
• The developed PTUs offer a sustainable solution due to their recyclability.
• The study provides insights into the mechanism governing the dynamic behavior of these novel polymer networks.