Abstract: Expanded vitrified microspheres were modified with two different fluorocarbon surfactants, and the influence of expanded vitrified microspheres surface characteristics on the foamability, the foam stability, the sealability to oil and the burning resistance of three phase foam was researched. The results showed that the increase of microsphere hydrophobicity (that is to increase the contact angle of solid and water) was helpful to improve the foamability and stability when the contact angle was in the range of 0o ~90o . For the three phase foam for oil fire control and extinguishing, the stronger oleophobicity of microspheres than the hydrophobicity is more effective to improve the foam stability, the sealability to oil and the burning resistance of three phase foam. When the liquid drained from the modified three phase foam, the gas was not easy to exhaust, so a watergas two phase foam area was formed between the three phase foam and the gasoline, which could last for nearly 10 h. Finally, the gas was completely released at the junction of the three phase foam and the breaker wall (the weakest place), indicating that the three phase foam is extremely dense and stable.

Key words: three phase foam, expanded vitrified microsphere, sur? face characteristic, extinguishing agent for oil fires