Novel high‐performance wave‐transparent aluminum phosphate/cyanate ester composites

Abstract

Advanced wave-transparent composites are the key materials for many cutting-edge industries including aviation and aerospace, which should have outstanding heat resistance, low dielectric constant and loss as well as good mechanical properties. A novel kind of high-performance wave-transparent composites based on surface-modified aluminum phosphate AlPO 4 (KH-550) and cyanate ester (CE) was first developed. The dielectric and dynamic mechanical properties of AlPO 4 (KH-550)/CE composites were investigated intensively. Results show that AlPO 4 (KH-550)/ CE composites have decreased dielectric loss and higher storage moduli than pure CE resin; in addition, the composites with suitable AlPO 4 (KH-550) concentration remain the outstanding thermal property and low dielectric constant of pure CE resin. The reasons attributing to these results are discussed from the effects of AlPO 4 (KH-550) on the key aspects such as morphology, curing mechanism, and interfacial adhesion of composites.

Low‐viscosity and soluble phthalonitrile resin with improved thermostability for organic wave‐transparent composites

“…Here, the dielectric properties of PPEBF‐Ph/QF and PB41/QF laminates were investigated in a waveguide cavity, and the results are presented in Figure . The laminates exhibited a dielectric constant of 2.94–3.27 and tan δ of 0.002–0.019 in an electromagnetic field at frequency ranging from 8 GHz to 18 GHz, values similar to that of many organic wave‐transparent materials that have been reported . The low polarizability of the CF/CH bonds and the absence of strong dipoles led to an obvious decrease of dielectric constant .…”

“…The laminates exhibited a dielectric constant of 2.94–3.27 and tan δ of 0.002–0.019 in an electromagnetic field at frequency ranging from 8 GHz to 18 GHz, values similar to that of many organic wave‐transparent materials that have been reported . The low polarizability of the CF/CH bonds and the absence of strong dipoles led to an obvious decrease of dielectric constant . Meanwhile, with the introduction of trifluoromethyl groups, the surface of the laminates manifested a hydrophobic phenomenon that was advantageous for the maintenance of a low dielectric constant .…”

“…Wave‐transparent composites for spacecraft require a low dielectric constant, excellent thermostability and mechanical properties, and good processability. Compared with inorganic wave‐transparent materials such as Si 3 N 4 , BN, SiC, and chrome–alumina compounds, organic wave‐transparent composites can be used in an wider frequency range and exhibit improved processability while having low thermostability and mechanical stability at elevated temperature.…”

“…Wave‐transparent composites for spacecraft require a low dielectric constant, excellent thermostability and mechanical properties, and good processability. Compared with inorganic wave‐transparent materials such as Si 3 N 4 , BN, SiC, and chrome–alumina compounds, organic wave‐transparent composites can be used in an wider frequency range and exhibit improved processability while having low thermostability and mechanical stability at elevated temperature. To achieve the desired integrated performance, cyanate ester, imides, polyhedral oligomer silsesquioxane, and other structures with high thermostability and mechanical properties have been incorporated into organic wave‐transparent materials in recent years .…”

Effect of boric acid on properties of high‐alumina phosphate‐bonded plastic refractory materials

“…Moreover, a phosphate binder is widely used in refractories, ceramics coating, and high‐temperature composites as an environmentally friendly binding agent, which possesses excellent properties such as strong bonding strength, low coefficient of thermal expansion, good thermal shock resistance, and excellent mechanical properties at medium to high temperatures. Phosphate‐bonded refractory materials are an important class of materials widely used in castable and plastic refractories.…”