Synthesis and characterization of silicon‐containing arylacetylene resins‐like heat‐resistant silane coupling agents: Enhancement of interfacial properties for composites

Abstract Silicon‐containing arylacetylene (PSA)‐based composites show excellent heat resistance and dielectric properties, making them highly promising for applications in the aerospace and electronic information fields. However, the low polarity of PSAs and poor interfacial adhesion with fibers lead to weak mechanical properties of their composites. In this study, a novel PSAs‐like heat‐resistant silane coupling agent (P‐SCA) was synthesized through Grignard reagent condensation reaction and used to modify the surface of quartz fiber (QF). Due to the special chemical structure of P‐SCA, the siloxanes in P‐SCA can undergo dehydration condensation with silicon hydroxyl groups on the quartz fiber cloths and graft onto the surface, while the alkynes in P‐SCA can react with the PSAs resin, enhancing the interfacial bonding by forming strong mechanical interlocking and chemical bonds. The composite prepared by quartz fiber cloth treated with 3.5 wt% P‐SCA (QF@3.5%P‐SCA) shows that the interlaminar shear strength (ILSS) and flexural strength are 21.0 and 270.6 MPa at room temperature, respectively, which have increased by 32.1% and 63.2%, respectively. And at 500°C, the ILSS and flexural strength are 9.3 and 131.7 MPa, increasing by 44.3% and 50.7%, respectively. The mechanical properties of QF@P‐SCA/PSA composites are significantly improved while maintaining their excellent heat resistance. Hightlights A heat‐resistant silane coupling agent with alkynes was synthesized. The high temperature resistant interface is constructed by the coupling agent. Mechanical interlocking and chemical bonding can occur at the interface. The composites showed good mechanical properties at elevated temperature.