Easily Processable Thermosets with Outstanding Performance via Smart Twisted Small-Molecule Benzoxazines

Area of Science:

• Polymer Chemistry
• Materials Science

Background:

• High-performance aromatic polymers offer desirable thermal, mechanical, and electrical properties but often suffer from poor processability.
• Achieving both outstanding performance and good precursor processability in aromatic polymers remains a significant challenge.

Purpose of the Study:

• To develop a new class of small-molecule benzoxazine resins that achieve an exceptional balance between processability and high performance.
• To investigate the structure-property relationships governing the processability and performance of these novel benzoxazine resins.

Main Methods:

• Synthesis of small-molecule benzoxazine resins featuring ortho-maleimide functionality.
• Characterization of molecular configurations and polymerization behavior.
• Evaluation of thermal stability, flame retardancy, and dielectric properties of the resulting polymers.

Main Results:

• The ortho-maleimide substitution induces twisted molecular configurations, enhancing precursor processability by preventing intermolecular packing.
• Multiple polymerization routes lead to the elimination of twisted structures and the formation of highly cross-linked polymer networks.
• The resulting polymers exhibit high thermal stability (no glass transition temperature detected before 400 °C), excellent flame retardancy (42.5 J g⁻¹ K⁻¹ heat release capacity), and low dielectric constants (2.62–2.30 from 1 Hz to 10 MHz).

Conclusions:

• The novel ortho-maleimide-functionalized benzoxazines provide a versatile platform for creating high-performance thermosets.
• These materials demonstrate a remarkable combination of processability and advanced properties, suitable for aerospace, transportation, and electronic packaging.
• The study highlights the potential of "smart" benzoxazines in developing next-generation advanced materials.