Synthesis of Polyether‐Modified Polyfluorosiloxane and Defoaming Evaluation of Its Emulsion

ABSTRACT Polyether‐modified polysiloxane is widely used in emulsion defoamer formulations. In this study, we introduced the fluoroalkyl group to prepare polyfluorosiloxane (FHPS) and polyether‐modified polyfluorosiloxane (FEPS) via ring‐opening polymerization and hydrosilylation. After optimization, the yield of FHPS can reach 78.57%, with a surface tension of 17.24 mN·m −1 ; the yield of FEPS is 93.16%, with a surface tension of 20.68 mN·m −1 . The synthesized FEPS exhibits good thermal stability with a critical micelle concentration of 21.37 mg·L −1 . Then, emulsion defoamers were formulated using FEPS as de‐ and anti‐foaming components. The best emulsion has an average particle size of 15.11 μm, which was prepared by the phase inversion method. In the sodium dodecylbenzene sulfonate (SDBS) solution, the foam elimination time is 7.0 s, and the antifoam time is 45.2 min. In the rhamnolipid solution, the foam elimination time is 7.4 s, and the antifoam time is 40.8 min. The synthesized polyether‐modified polyfluorosiloxane shows great potential for application in defoamers.