High temperature composite materials for electromagnetic applications through a cost effective manufacturing process; resin film infusion

Abstract

High temperature materials with low dielectric loss properties are always in high demand for aviation and electronic sectors. Effective microwave communication, tracking of aircrafts through radomes and encapsulation of electronic integrated circuitries from damages caused by dielectric heat buildup essentially requires low-loss materials. Materials for these applications are always expensive. Hence, an attempt has been made to develop such materials by blending Bisphenol A Cyanate ester with Bisphenol A epoxy at various epoxy weight fractions to realize composites through a cost-effective fabrication process called Resin Film Infusion (RFI). Epoxy has been chosen so the resultant blends become an economically viable solution for its intended applications. The composition of these blends was optimized considering their ease of being cast to thin films, with appropriate tackiness at ambient conditions. Rheology was used as a tool to determine the processing conditions for subsequent composites manufacturing through RFI. Dynamic Mechanical Analysis was used to evaluate the thermo-mechanical properties and it confirms a glass transition temperature of more than 250 °C for the formulation. Composite laminates were realized using E-glass (GFRP) fabric reinforcements. Evaluation of their mechanical properties revealed that cyanate ester/epoxy blends resulted in composites with excellent mechanical properties. Laminate using quartz fabrics (QFRP) was also realized for electromagnetic measurements. The low transmission loss of (−0.70 dB to −1.3 dB) for GFRP and −0.1 dB to −0.4 dB for QFRP in L and S microwave bands illustrates that, this matrix formulation can be used for composite radomes and encapsulating electronic circuitries.