Preparation and Properties of High‐Temperature‐Resistant and Low‐Dielectric Constant Silicon‐Containing Arylacetylene Resin/SiO ₂ Syntactic Foams

A silicon‐containing arylacetylene resin (PSA)/SiO ₂ syntactic foam was prepared through a chemical foaming approach, with PSA serving as the matrix, quartz sand (QS) and nanosilica (nSiO ₂ ) acting as fillers, and their structures and properties were characterized. The results show that the incorporation of appropriate amounts of QS and nSiO ₂ can reduce the cell size and apparent density of the syntactic foam, and improve its heat resistance, dielectric properties and wave transmission properties. The addition of QS can increase the compressive strength of the syntactic foam, while the addition of nSiO ₂ decreases the compressive strength. The apparent densities of the PSA/9QS and PSA/9nSiO ₂ syntactic foams with 9% filler addition are 0.242 g cm ⁻³ and 0.157 g cm ⁻³ , respectively, and the temperatures at 5% weight loss ( T _d5 ) under a nitrogen atmosphere were 692 °C and 658 °C, respectively. The dielectric constants were 1.59 and 1.25, respectively. The wave transmittance within the frequency range of 8.2–12.4 GHz was 98.5% and 96.8%, respectively. PSA/SiO ₂ syntactic foam can be used as a lightweight and high‐temperature‐resistant wave‐transmission material in aerospace and other fields.