Simultaneously enhanced cryogenic mechanical behaviors of cyanate ester/epoxy resins by poly(ethylene oxide)‐co‐poly(propylene oxide)‐co‐poly(ethylene oxide) (PEO‐PPO‐PEO) block copolymer and clay

Abstract

Cryogenic mechanical properties are important parameters for thermosetting resins used in cryogenic engineering areas. The hybrid nanocomposites were prepared by modification of a cyanate ester/epoxy/poly(ethylene oxide)‐block‐poly(propylene oxide)‐block‐poly(ethylene oxide) (PEO‐PPO‐PEO) system with clay. It is demonstrated that the cryogenic tensile strength, Young's modulus, ductility (failure strain), and fracture resistance (impact strength) are simultaneously enhanced by the addition of PEO‐PPO‐PEO and clay. The results show that the tensile strength and Young's modulus at 77 K of the hybrid nanocomposite containing 5 wt% PEO‐PPO‐PEO and 3 wt% clay were enhanced by 31.0% and 14.6%, respectively. The ductility and impact resistance at both room temperature and 77K are all improved for the hybrid composites. The fracture surfaces of the neat BCE/EP and its nanocomposites were examined using scanning electron microscopy (SEM). Finally, the dependence of the coefficients of thermal expansion (CTE) on the clay and PEO‐PPO‐PEO contents was examined by thermal dilatometer. POLYM. COMPOS., 38:2237–2247, 2017. © 2015 Society of Plastics Engineers