Preparation Of Fluorine-containing Aqueous Coatings

With the environmental pollution,green chemical industry has gradually become the theme of the times.Fluoropolymer has a more widely used prospects and market prospects,due to its unique performance in the theoretical research and industry.In this paper,a series of fluorine-containing polymer emulsions with different structures were synthesized from the view of environmental-friendly fluorosurfactants,and the aqueous coatings were prepared successfully.It has great practical significance towards the development of environmentally friendly direction for China's paint industry.A novel fluorinated surfactant,sodium 1H,1H,7H-dodecafluoro-1-heptyloxy acetate,was synthesized via a facile two-step synthetic procedure.The chemical structure of the obtained surfactant was characterized by ¹H NMR,¹⁹F NMR and FT-IR.UV absorption and ring measurements were performed to obtain the detailed information of surface properties.The results demonstrated that the novel surfactant possessed very low critical micelle concentration?CMC,1.12 mM?and surface tension?20.01 mN/m?.Furthermore,the surfactant had preferable thermal stability compared with other perfluorocarboxylates characterized by thermal gravity analysis?TGA?.The new synthetic fluorosurfactant has excellent surface properties by calculating the molecular adsorption capacity and Gibbs free energy of the newly synthesized fluorosurfactant.An aqueous binary or ternary fluoropolymer emulsion based on chlorotrifluor ethylene?CTFE?,vinylidene fluoride?VDF?and vinyl ether was finally obtained,which the newly synthesized fluorinated surfactant was used as an emulsifier.In the polymerization system,the effect of polymerization conditions on the emulsion was studied,and the optimum polymerization conditions were determined.The structure and composition of the fluoropolymer resin were characterized by NMR(¹H NMR,¹⁹F NMR),infrared?FT-IR?,scanning electron microscopy?SEM?and laser particle size analyzer.In order to obtain the optimum emulsion polymerization conditions,the effect of the factors such as the concentration of the initiator and the reaction time on the polymerization conditions was studied in detail.When the polymerization time was 8 h and the initiator concentration?mass concentration?was 0.3%,a fluorine-containing polymer emulsion has a higher yield.When the molar ratio of vinylidene fluoride?VDF?and perfluoro n-propyl vinyl ether?PPVE?was 5:1,the highest yield was obtained.Through the analysis of the mechanical stability,the particle size and morphology of the latex particles for the fluorinated emulsion,it was confirmed that the obtained fluoropolymer emulsion had better stability.Emulsion polymerization is a very mature polymerization technology in producing polymer materials of high performance in industry,which can meet the production requirements of industry.The preparation of fluorinated polymer emulsions is an important technology for the production of fluorine-containing materials.Among them,an important usage of fluoropolymer emulsion is the preparation of fluorine-containing water-based paint,with the increasingly serious environmental pollution,fluorine-containing water-based paint can improve the environmental pollution caused by the solvent-based coatings in paint industry.In addition,the fluorine-containing water-based paint has important meaning for the improvement of the core competitiveness.In this paper,we synthesized a new environment-friendly fluorosurfactant,and then the fluorine-containing polymer emulsion with relatively stable performance was prepared,the water-based coating was prepared finally.The whole process was more environmentally friendly and therefore it had higher application as well as market prospects.