| Elemental boron is used as additive to improve the heat of combustion of liquid hydrocarbon fuels because of its high gravimetric and volumetric heat of combustion. But due to the characteristics of boron, it is very difficult to disperse in liquid hydrocarbon fuels, which seriously limits its application in the preparation of high energy fuels.To solve the above problem, two methods have been used to realize the boron particles dispersed in the hydrocarbon fuels steadily. One is addition of surfactants and the other is chemical modification. The details are discussed below:1. Several different kinds of surfactants and dispersing agents were used to help boron particles disperse in liquid hydrocarbon fuels effectively. It was found that Span-80 can make the boron powder disperse in decalin uniformly. Meanwhile, TOPO as a dispersing agent can also help the dispersibility of boron particles.2. Modified boron particles with hexadecyltrimethoxysilane (HTMS) shows an improved dispersibility in decalin. The appropriate reaction conditions are as follows: T= 70℃, reaction time= 1 h, and the mass ratio of silane to boron NPs=1:1.3. It was found that boron particles can disperse in JP-10 and aviation kerosene fuels well after being modified by silane. When boron pretreatment by HC1, then modified with TOPO, they can also suspend in JP-10 steadily. We discuss the mechanisms of two methods. Various techniques were used to characterize modified boron NPs such as X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA), dynamic light scattering measurement (DLS).4. The dispersing mechanism of boron in hydrocarbon fuels was discussed, and it was found that the stability of the suspension related to the nature of base fuels, surface hydrophobicity and size of boron particles. |
PDF Full Text Request