Abstract:

Non-aqueous foams have a wide range of applications in petroleum exploitation, functional materials, daily chemical industry, etc. However, the low interfacial tension and low dielectric constant of non-aqueous solvents lead to the difficulty in forming stable foams. Therefore, to solve the difficulty in foaming for non-aqueous systems, nano-SiO₂ particles were prepared and characterized by TEM, FT-IR and XRD. Then the wettability of nano-SiO₂ particles was modified with 3-glycidyloxypropyl trimethoxysilane （GPTMS）, and the effects of nano-SiO₂ particles of different wettability on the foaming performance of non-aqueous solvents were studied. The results showed that the contact angle of the particles could be regulated in the range from 34.7° to 116° by GPTMS modification. The surface tension of different solvents could be effectively reduced and the viscosity of the solvent systems was increased. When the mass fraction of particles was 7% and the particle size was 10 nm, the foam volume for non-aqueous solvents first increased and then decreased with the increase of the contact angle of nano-SiO₂ particles, and the foam stability also first increased and then decreased with the increase of the contact angle of nano-SiO₂ particles. In the formamide system, when the contact angle of particles was 92.3°, the foam volume could reach up to 12 mL, and the foam stability could reach 63 days. In the benzyl acetate system, when the contact angle of particles was 79.5°, the foam volume could reach up to 7 mL, and the foam stability could reach 47 days. In the decane system, when the contact angle of particles was 60.3°, the foam volume could reach up to 4 mL, and the foam stability could reach 8 days.

Key words: non-aqueous foam, nano-SiO₂ particle, wettability, foaming performance, stability