A hydrogen bonding strategy for enhancing thermal and mechanical properties in high-performance poly(imino arylene ether nitrile)

Developing high-performance materials with stability in extreme environments remains a key challenge in materials science. In this work, a novel polymer, poly(imino arylene ether nitrile) (PIEEN), was successfully synthesized through a nucleophilic substitution reaction. The incorporation of imino and nitrile groups into the backbone facilitated the formation of robust intermolecular hydrogen bonds within the polymer matrix, significantly enhancing its thermal properties, as evidenced by a glass transition temperature (Tg) of 206°C and a decomposition temperature (T5%) of 410°C. Additionally, the reversible dissociation and reformation of hydrogen bonds under stress contributed to remarkable mechanical performance, achieving a tensile strength of 135 MPa and an elongation at a break of 31%. This dual enhancement of strength and toughness represents a significant breakthrough in addressing the longstanding trade-off between rigidity and toughness in rigid polymers. The results provide a promising pathway for designing high-performance polymeric materials.