Preparation and performance of fumed silica-stabilized epoxy resin pickering emulsion for basalt fiber–sizing agents

Abstract: Increased requirement of environmental durability has fostered the development of emulsifier-free emulsions for sizing agents to reduce the volatile organic compounds while improving hydrothermal aging performance of fiber-reinforced polymers. This paper reports the use of fumed silica modified by trace amounts of cationic surfactant cetyltrimethyl ammonium chloride (CTAC) to stabilize epoxy resin Pickering emulsions for basalt fiber–sizing agents. When 4 mass% of fumed silica aqueous colloid was modified by only 0.004 mass% of CTAC, a stable Pickering epoxy resin emulsion with the mean diameter of droplets of 3.121 µm was obtained by the mechanical emulsification method. Compared with the emulsion prepared by phase inversion emulsification with a large amount of chemical emulsifier, the surface energy, interfacial shear strength, impregnated yarn tensile strength, and unidirectional BFRP flexural strength of BF-sized only by the prepared Pickering emulsion are increased by 43.5%, 14.1%, 12.7%, and 27.1%, respectively. Especially, the impregnated yarn’s tensile strength and unidirectional fiber-reinforced polymer’s flexural strength of basalt fiber sized by the Pickering emulsion after hydrothermal treatment were increased by 55.2% and 120.9%, respectively. Pickering emulsions showed potential application in fiber-sizing agents. Graphical abstract: [Figure not available: see fulltext.]