Abstract
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.
Highlights
Transmittance materials are primarily applied in radome manufactures to ensure that the antenna device system operates smoothly in remote control and communications, resisting the mechanical, thermal, electrical, and chemical impacts in harsh environments
Results and Discussion flat, while the fracture of Cyanate ester (CE)/epoxy resin (EP) composite shows an increment of ductile-vortex grooves with short cracks
The self-polymerization reaction occurs in the CE monomer matrix after being heated to curing temperature to form the regularly reticulated configurations of densely distributed triazine-rings, which are capable of restricting the molecular segments to a stable state below a specific high temperature [31], whereas EP or BMI reinforcement will abate the regularity of CE reticulated configurations and reduce the intermolecular forces, resulting in a decreased kinetic energy needed for molecular chains to escape from van der Waals interactions at a lower Tg
Summary
Transmittance materials are primarily applied in radome manufactures to ensure that the antenna device system operates smoothly in remote control and communications, resisting the mechanical, thermal, electrical, and chemical impacts in harsh environments. Resin-based transmittance materials are preferred for their higher tenacity in a sufficient temperature range, which can be obtained through a casting molding process used for radome fabrications [6,7]. Breakable chain segments produced from the group reactions of amino-terminal polypropylene and CE trimers can be embedded in the backbone of the cured network to decrease the crosslinking density and increase the tenacity of CE resin, which will degrade electrical resistance and dielectric properties [6]; CE/carbon-fiber composites obtained through complex synthesis processes inherit the unique mechanical and heat-resistant characteristics of carbon fiber, they show a significantly decreased wave-transmittance due to the high dielectric permittivity of carbon fiber [20]. Aluminum acetylpyruvate [21] as the catalysis for expediting the curing reactions were blended into the CE matrix and processed through the thermosetting reactions to develop a significantly modified transmittance material of ternary copolymer composite, which were experimentally verified by analyzing the mechanical, heat-resistant, and dielectric properties
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
