Abstract: The material used for the domestic radar cover is glass fiber/epoxy prepreg prepared by solution impregnation method currently, the prepreg prepared by solution impregnation method has problems such as difficulty in accurately controlling resin and volatile content, as well as environmental pollution caused by solvent volatilization. The glass fiber/epoxy prepreg (ES78/E40) were prepared by hot-melt film method using domestic raw materials, and the physical properties of the ES78/E40 prepreg were systematically researched as well as the mechanical and flame retardant properties of the composite material. The relevant properties of prepreg prepared by solution impregnation method were compared. The results show that the physical, mechanical, and flame retardant properties of ES78/E40 prepregs meet the requirements. The room temperature tensile strength and compressive strength of domestically produced prepregs were 517 MPa and 443 MPa, respectively, and the tensile and compressive strength retention of composites was about 80% at 71 ℃; compared with the performance of prepreg prepared by solution impregnation method, the tensile and compressive properties have been improved by 11.8% and 9.9%, respectively. ES78/E40 prepreg can be applied to secondary load-bearing structural components such as domestic radar covers.

Key words: hot-melt film method, prepregs, mechanical properties, dielectric properties, composites