Study on the non-aqueous foams stabilized by the modified nano-SiO2 particles
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.
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