Cyanate Ester Resins: Synthesis, Curing, and Beyond

Cyanate ester (CE) resins constitute a pivotal family of high-performance thermosets, characterized by exceptional thermal stability, low dielectric loss, minimal moisture uptake, and robust mechanical properties. These attributes render them highly desirable demanding applications in aerospace, microelectronics, radar-transparent components, and advanced composites. However, a comprehensive overview that systematically integrates synthetic strategies, curing chemistries, structure–property correlations, and state-of-the-art applications remains absent. This review fills this gap by providing a cohesive and critical survey of CE resins, spanning their development history, synthetic pathways, curing chemistry, key properties, and diverse applications. Major synthetic routes for CE monomers are categorized and evaluated in terms of mechanistic principles and practical viability. Complex curing systems including self-catalysis, active hydrogen-initiated curing, transition-metal catalysis, and other modified approaches are delineated, with emphasis on methods to lower curing temperatures. Critical properties such as mechanical, dielectric, thermal, and adhesive behaviors are analyzed, revealing the governing role of the triazine-ring network structure. Representative advances in key application areas such as high-frequency circuit substrates, radomes, aerospace composites, high-temperature adhesives, and polymer modifications are highlighted. By consolidating these perspectives, this review establishes a unified framework for understanding CE resins and identifies promising research directions for enhancing their sustainability, functionality, and industrial relevance.