Ameliorated Mechanical and Dielectric Properties of Heat-Resistant Radome Cyanate Composites

Abstract

<jats:p>In order to improve the mechanical and dielectric properties of radome cyanate, a synergistic reinforcement method is employed to develop a resin-based ternary-composite with high heat-resistance and preferable radar-band transmission, which is expected to be applied to fabricate radomes capable of resisting high temperature and strong electric field. According to copolymerization characteristics and self-curing mechanism, epoxy resin (EP) and bismaleimide (BMI) are employed as reinforcements mixed into a cyanate ester (CE) matrix to prepare CE/BMI/EP composites of a heat-resistant radome material by high-temperature viscous-flow blending methods under the catalysis of aluminum acetylpyruvate. The crystallization temperature, transition heat, and reaction rate of cured polymers were tested to analyze heat-resistance characteristics and evaluate material synthesis processes. Scanning electron microscopy was used to characterize the micro-morphology of tensile fracture, which was combined with the tensile strength test and dynamic thermomechanical analysis to investigate the composite modifications on tenacity and rigidity. Weibull statistics were performed to analyze the experimental results of the dielectric breakdown field, and the dielectric-polarization and wave-transmission performances were investigated according to alternative current dielectric spectra. Compared with the pure CE and the CE composites individually reinforced by EP or BMI, the CE/BMI/EP composite acquires the most significant amelioration in both the mechanical and electrical insulation performances as indicated by the breaking elongation and dielectric breakdown strength being simultaneously improved by 40%, which are consistently manifested by the obviously increased transverse lines uniformly distributed on the fracture cross-section. Furthermore, the glass-transition temperature of CE/BMI/EP composite reaches the highest values of nearly 300 °C, with the relative dielectric constant and dielectric loss being mostly reduced to less than 3.2 and 0.01, respectively. The experimental results demonstrate that the CE/BMI/EP composite is a highly-qualified wave-transmission material with preferences in mechanical, thermostability, and electrical insulation performances, suggesting its prospective applications in low-frequency transmittance radomes.</jats:p>

Voltage-Stabilizer-Grafted SiO2 Increases the Breakdown Voltage of the Cycloaliphatic Epoxy Resin

“…Based on the split strength model, the theoretical breakdown strength is positively correlated with the cohesive energy . The higher Young’s modulus means that the nanocomposite material can withstand the higher Coulomb force generated by the external electric field. , In other words, the m -ABA-SiO 2 nanoparticles in the CE-based nanocomposites may form strong physical support points to protect the nanocomposite from electromechanical failure. In Figure d, it is observed that pure CE is brittle under external force.…”

Curing Regime-Modulating Insulation Performance of Anhydride-Cured Epoxy Resin: A Review

“…Epoxy resin has been applied in the field of electrical insulation since the early 1950s. After more than 70 years of development, it has become a widely used insulating material in electrical equipment due to its excellent heat resistance, mechanical and insulation properties [ 1 , 2 , 3 , 4 , 5 ]. In gas-insulated metal-enclosed lines (GIL) and gas-insulated metal-enclosed switches (GIS), basin insulators or tri-post insulators made of epoxy resin as the main raw material through the casting process play a major role in supporting and insulating, and are key components of GIL/GIS foundation units [ 6 , 7 ].…”

Low-Dielectric Polymers Derived From Biomass

“…6−9 The other is increasing the free volume of the materials by introducing large-volume groups or increasing porosity. 10,11 Over the past few decades, researchers have developed a lot of low-k polymer materials, including epoxy resins, 12,13 polyimides, 14−17 cyanate ester resins, 18,19 benzoxazine resins, 20−22 benzocyclobutene resins, 6,23,24 and perfluorocyclobu-tyl-based resins. 25,26 However, most of those resins are produced through the petroleum-based feedstock, and the consumption of petroleum may lead the potential resource crisis.…”

“…Over the past few decades, researchers have developed a lot of low- k polymer materials, including epoxy resins, , polyimides, − cyanate ester resins, , benzoxazine resins, − benzocyclobutene resins, ,, and perfluorocyclobutyl-based resins. , However, most of those resins are produced through the petroleum-based feedstock, and the consumption of petroleum may lead the potential resource crisis. Therefore, developing the high-performance materials from renewable biomass to replace petroleum-based materials is very desirable. − Biobased feedstock can be easily prepared from nature, and it displays renewability, low pollution, and wide distribution .…”