Novel multifunctional microcapsule and its cyanate ester resin composites with self-healing ability and gamma radiation shielding ability

Resin-based composites used in spacecraft face risks from space debris and high-energy charged particles during their long-term service in the space environment. This work proposes a novel microcapsule (MC) and its cyanate ester (CE) resin-based composites (CE/MCs) with self-healing ability and gamma radiation shielding ability. The multifunctional epoxy/lead tungstate (EP@PWO) microcapsules are developed through self-assembly method and in-situ precipitation method. These microcapsules and curing agent 4,4′-diaminodiphenylsulfone (DDS) are incorporated into the CE resin to form resin-based composites with low curing temperature, self-healing ability, and gamma radiation shielding ability. Various approaches including chemical characterizations (X-ray diffractometer, fourier-transform infrared, energy dispersive spectrometer), microscopy (optical microscope, scanning electronic microscope), and thermal analysis (differential scanning calorimeter, thermogravimetric analysis) are utilized to demonstrate the successful encapsulation of the EP resin by PWO shell and good thermal stability of this material. The mechanical property, self-healing ability, and gamma radiation shielding property are investigated via fracture toughness test and using a NaI (Tl) spectrometer. In comparison with pure CE resin, the fracture toughness of the CE/MCs composites can increase by 66.5%, and the self-healing efficiency can reach up to 56%, indicating that the microcapsules have good toughening and self-healing abilities. The microcapsules and their composites also exhibit good gamma radiation shielding properties.