Synthesis and analysis of properties of a new core-shell silicon-containing fluoroacrylate latex

BACKGROUND: Silicon-containing fluoroacrylate copolymers are potential materials for use in the protection of ancient stone buildings. In the work reported in this paper, a new core-shell silicon-containing fluoroacrylate latex was prepared through grafting of a fluoroacrylate copolymer latex with polysiloxane. RESULTS: The core-shell silicon-containing fluoroacrylate latex was successfully synthesized by seed emulsion polymerization and octamethylcyclotetrasiloxane (D-4) ring-opening polymerization in the presence of a mixed emulsifier consisting of a non-ionic emulsifier and a novel fluorine-containing anionic emulsifier sodium perfluoro-octane sulfonate. Transmission electron microscopy, X-ray photoelectron spectroscopy, static contact angle measurements and scanning electron microscopy-energy dispersive X-ray analysis showed that when the D-4 content was controlled at 2.84-4.36 wt%, the silicon-containing fluoroacrylate latex presented a uniform sphere core-shell structure and had strong hydrophobic and oleophobic characters due to the association of both fluorine and silicon atoms on the latex film surface. The film cross-section exhibited uniform and dense microstructure without any phase segregation. Additionally, thermogravimetric analysis and tensile test results indicated that all the silicon-containing fluoroacrylate copolymers displayed better thermal stability and higher flexibility. CONCLUSION: The synthetic core-shell silicon-containing fluoroacrylate latex showed excellent surface properties, thermal stability and flexibility, and has encouraging prospects in application as a protective coating. (C) 2009 Society of Chemical Industry