Polyarylacetylene as a novel graphitizable precursor for fabricating high-density C/C composite via ultra-high pressure impregnation and carbonization

High-density carbon/carbon (C/C) composite plays a critical role in the aerospace industry owing to excellent mechanical properties and resistance to ablation. However, traditional manufacturing relies on pitch precursor and hot isostatic pressure impregnation and carbonization (HIPIC) technology, which is time-consuming and expensive. In this study, we report an innovative method utilizing polyarylacetylene (PAA) resin and ultra-high pressure impregnation and carbonization (UHPIC) technology. The extremely high char yield of PAA resin (85 wt.%) and high isotropic pressure of UHPIC (over 200 MPa) promote the densification of the composite. As a result, we achieve a high-density (1.90 g/cm3) C/C composite with a high degree of graphitization (81%). This composite exhibits impressive properties, including flexural strength of 146 MPa, compressive strength of 187 MPa, and thermal conductivity of 147 W/(m K). When exposed to oxyacetylene flame at 3000 K for 100 s, it displays minimal linear ablation, with a rate of 1.27×10−2 mm/s. This study demonstrates the exceptional graphitizable characteristic of PAA resin, setting it apart from conventional resins. Our time-saving and cost-effective approach holds significant promise for aerospace applications, particularly in harsh aerodynamic heating environments.