| As one of the most important categories of protective textiles, acid-resistant textiles have been used in many fields, such as petro, chemistry, metallurgy and electroplating. The fluorochemicals are the most favorable acid-proof agents at present due to their excellent and durable stability to acids. But these long fluoroalkyl chains polymer are high cost and unfriendly to the environment. Therefore, the organic-inorganic composite emulsion with short fluoroalkyl chains was prepared and applied on the textile acid-proof finishing in this paper.Aqueous monodisperse nano-SiO2/fluorine-containing polymer hybrid emulsion with core-shell structure was sucessfully synthesized by in-situ emulsion polymerization and two step polymeric process. Firstly, the composite emulsion were prepared using highly monodisperse spherical silica nanoparticles as seeds and polyacrylates and poly(fluorinated acrylates) as shells. Secondly, the structures and properties of composite emulsion were discussed. Finally, the hybrid emulsion was applied in acid-proof finishing.Highly monodisperse spherical silica nanoparticles were prepared with KH-570 via one-step emulsion reaction in aqueous solution, using nonylphenol poly(oxyethylenic) (OP-10) and sodium dodecyl sulfonate (SDS) as emulsifier and ammonium hydroxide as catalyst. The factors affecting the size of silica nanoparticles were studied such as the amount of emulsifier, the amount of catalyst, the amount of KH-570, the reaction temperature and the reaction time.Nano-SiO2/fluorine-containing polymer hybrid emulsion was synthesized by emulsion copolymerization, using dodecafluoroheptyl methacrylate, butyl acrylate and methyl methacrylate as monomers, SDS and OP-10 as co-emulsifier, and ammonium persulfate as initiator. Meanwhile, the performance of polymerization emulsion was evaluated by conversion rate, coagulation rate, particle size, stability, water absorption of the emulsion film and film formation. The experimental results showed that the nano-sio2/fluorine-containing polymer hybrid emulsion can be prepared when the polymerization temperature was 80℃, the reaction time was 4h, the amount of emulsifiers was 4%, the mass ratio of anionic emulsifier to nonionic emulsifier was 1:2, the amount of initiator was 0.4%, and the amount of silica nanoparticles was 6%. Fourier-transform infrared (FTIR) spectrometry, particle size analysis, and thermogravimetric analysis (TGA) were performed to characterize the structures and properties of the hybrid emulsion. The test results showed that the graft copolymer was successfully prepared by the copolymerization of nano-SiC^, acrylates and fluorinated acrylate. The nano-SiO2/fluorine-containing polymer hybrid emulsion had excellent dispersion stability and thermal stability. And its average particle size was about 132nm.The composite emulsion was applied to the polyester fabric. The surface morphologies and elemental compositions of both untreated and treated polyester fabrics were characterized by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), respectively. The effect of different finishing conditions on the acid repellency of polyester fabrics was discussed. The results showed that the optimal finishing conditions were as follows:the finishing agent 70 g/L, pickup 70%-80%, curing at 160℃for 180 s. Under these conditions, the water contact angle of the treated polyester fabric was 150°, the acid penetration time was more than 30 min and the acid-proof efficiency indexwater was more than 90%.
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