Synergistic improvement of toughness and thermal properties of phthalonitrile resin based on the multiple curing mechanism of amino-carborane

This work leverages synergistic curing and microphase separation within the system to tackle the trade-off between temperature resistance and toughness in phthalate resin. • A novel oligo (aryl ethers) with intrinsic dual effects of curing and toughening. • Innovative exploration of the amino-carborane dual-curing mechanism. • Achievement of synergistic enhancements in both toughness and thermal stability. • The boron oxide “scale armor” layer as an effective shield against thermal shock. Ultra heat-resistant phthalonitrile resin has faced serious challenges of the trade-off between temperature resistance and toughness and seriously affects its application in the field of temperature resistant structural composites. In this work, a kind of oligo (aryl ethers) containing phenyl-s-triazine and pendent amino group (AFT-Ph/PAFT-Ph) were first selected as modifier co-cured with phthalonitrile prepolymers containing a carborane (CEPN) to achieve synergistic improvement in toughness and heat resistance performance. The flexural and impact strengths of optimized composites reach 278.6 MPa and 58.4 kJ/m 2 , which are increased by 92.7 % and 1091.8 % compared to the blank contrast. The glass transition temperature ( T g ) remained consistent with that of the blank control group, both exceeding 550 ℃. Furthermore, the T d5% –N 2 shows a marginal increase from 706 ℃ in the blank contrast to 713 ℃ in the modified material. Simultaneously conducting research on the mechanism of collaborative improvement mentioned above.