Properties of epoxy resin matrix composites improved by silica sol-activated hollow ceramic microspheres

Silica sol can activate the surface of hollow ceramic microspheres and improve the properties of composite materials by improving the interface between the microspheres and the epoxy resin. The group changes on the surface of microspheres were measured using infrared spectroscopy. The microspheres were observed with a scanning electron microscope. The density, water absorption, and mechanical properties of the materials were tested using scales and mechanical testing machines. The results showed that SiO2 and silane molecules were introduced on the surface of the microspheres after treatments. As the silica sol content increased, the slurry viscosity increased by 34.5%, the composite density increased by 5.8%, and the water absorption decreased by 35.8%. When the silica sol content was 25%, the flexural strength and compressive strength of the composites were 73.49 and 116.27 MPa, respectively, which were 37.8% and 23.6% higher than those of the untreated composites, and the mechanical properties became clearly improved. High mechanical properties enable the materials to be used in deeper ocean areas.Highlights Nanoparticles are introduced onto the surface of hollow microspheres. The activated microspheres can bind better to the silane coupling agent. Silane coupling agent assisted by silica sol improved interfacial bonding. Surface activation of microspheres improves the properties of composites. The surface of the hollow microsphere was treated with KH550 after SiO2 particles were introduced. The untreated green and treated yellow samples were prepared by mixing the microspheres with epoxy resin matrix. The properties of the treated samples were greatly improved. image