Research on properties of composite based on polyether sulfone/cyanate ester semi‐interpenetrating resin system

Abstract Cyanate ester (CE) resin is usually used as high‐temperature resistant or microwave absorbing material in aerospace field because of its high‐glass transition temperature, low‐curing shrinkage, and excellent dielectric properties. However, CE resin has the disadvantages of high‐curing temperature, high brittleness, and poor toughness, which limits its application in the field of aerospace. In this article, CE resin is modified by high‐performance thermoplastic engineering plastic polyether sulfone (PES) to obtain a modified resin with excellent toughness. The thermoplastic/thermosetting semi‐interpenetrating network system formed by PES and CE resin can greatly improve the mechanical and thermal properties of PES modified CE resin. The results show that the flexural strength and impact toughness of CE resin castings modified with 10 wt% PES are 56% and 63% higher than those of CE resin castings. At 800°C, the retention weight of CE resin castings with 12.5 wt% PES content increased from 19.0% to 28.1%, which shows that the heat resistance of CE resin is greatly improved by PES. Compared with carbon fiber reinforced CE resin (CF/CE) unidirectional composite, the flexural strength of CF/CE‐P‐10 composite is increased from 1649.6 to 1959.8 MPa; the interlaminar shear strength is increased from 61.3 to 84.2 MPa; the impact strength is increased from 225.9 to 346.4 kJ/m 2 ; and the interlaminar fracture toughness is increased from 5.34 to 11.38 J/m 2 .