Synergistic enhancement of processability and thermal properties in phthalonitrile resins via incorporation of silicon-containing arylacetylene

Phthalonitrile (PN) resin has attracted significant attention due to its exceptional thermal stability and mechanical properties. However, the requirement for elevated curing temperatures remains a critical challenge for their widespread practical applications. In this study, phthalonitrile containing branched cyanine (BPN) was blended with silicon-containing arylacetylene (PSA) to investigate their synergistic curing effects. The 10 wt% PSA formulation offers an optimal trade-off, demonstrating that moderate PSA loading synergistically enhances both processability and thermal stability without compromising high-temperature mechanical robustness: a reduction of the initial curing temperature from 234.3°C to 198.7°C and a decrease in the melting point from 161.6°C to 147.4°C. Conversely, the processing window expanded from 41.3°C to 54.7°C. Furthermore, the system exhibited enhanced thermal stability, evidenced by an increase in the 5% weight loss temperature ( T d5 ) from 530.33°C to 552.38°C and a rise in the char yield from 75.73% to 80.13%. No distinct glass transition was detected below 400°C, indicating a substantial improvement in both the processability and thermal stability of the blend system. Although the incorporation of PSA resulted in a slight reduction in the mechanical properties of BPN, the blends retained excellent mechanical performance at elevated temperatures, surpassing the room-temperature properties of PSA. The findings significantly enhance the industrial viability of phthalonitrile-based materials, effectively paving the way for their large-scale deployment in high-performance sectors.