Polyacrylates With Water-Oil Repellent And Flame Retardant Properties: Synthesis And Applications

With the improvement of people's living standard, the functionality of textiles become the focus of interest in the market. The multi-functional fabric finishing agent is the major trend in the future. Consequently, finishing agents combined with water and oil repellency and flame retardant properties are highly desirable. The fluorine-containing finishing agents especially those with long perfluoroalkyl chains (C_nF_2n+1, n≥8) are widely used as the most important class of water and oil repellent finishing agents. However, the fluorocarbons containing long perfluoroalkyl chains can be degraded into perfluorooctanesulfonates (PFOS) and perfluorooctanic acid (PFOA) and their related compounds which can not be degraded further in the environment. These compounds accumulate in human beings, animals and plants and can be toxic. The use of fluorocabons with long perfluoroalkyl chains will be restricted in the international community. Therefore, it is important to find the alternatives for the market.In this paper we designed and synthesized a series of fluorine- and phosphor- containing polyacrylates which can be used as finishing agent for cotton fabrics. Firstly, starting from commercially available lH,lH,2H,2H-perfluorooctanol, acrylic acid, allyl bromide, triethylphosphite, diethyl chlorophosphate, acryloyl chloride and ethanolamine, the fluorinated acrylate monomer 1, the phosphor-containing monomers 2 and 3 were synthesized respectively. The above obtained monomers were copolymerized with other acrylate monomers by emulsion polymerization to provide multi-functionalized copolymers PFPA1 and PFPA2 respectively. Secondly, a series of novel phosphate-containing fluorinated monomers 3a, 3b, 4a, 4b, 5a, 5b, 6a and 6b were synthesized starting from phosphorus trichloride, fluorine-containing alcohols, (methyl)acryloyl chloride and ethanolamine respectively. These monomers were copolymerized respectively with other monomers to provide copolymers PFPA 3-8. The length of fluorocarbon chains was changed to investigate the impact to water and oil repellent and flame retardant properties of finished fabrics. The influences of polymerization conditions, such as concentration of emulsifying agents and initiator were studied. As a result all the polymerization conditions were optimized. The copolymers were characterized by FT-IR, TGA and DSC analysis.Under the optimized finishing condition, the cotton fabrics were treated with emulsions of PFPA 1-8. The change of external geometry morphology of the fabric before and after treatment was analysed by SEM. The flame retardant mechanism of fabrics after finishing were investigated by thermogravimetric analysis (TGA) , scanning electron microscope (SEM) and digital photograph. Fabrics treated with PFPA1, PFPA2, PFPA7 and PFPA8 showed good water and oil repellent properties with contact angle of 130°for water and of 110°for n-dodecane. However, only the fabrics treated with PFPA2 showed good flame retardant property with limiting oxygen index (LOI) of 26%. The fabrics treated with PFPA1, PFPA7 and PFPA8 had low limiting oxygen index (LOI 21.4%, 20.3%, 20%) . Fabrics treated with PFPA3, PFPA4, PFPA5 and PFPA6 showed general water repellency with contact angle about 125°. But the fabrics treated with PFPA3 and PFPA4 showed good flame retardant property with LOI of 26% and 25.8% respectively. And the flame retardant properties of the fabrics treated with PAPA5 and PFPA6 were general with LOI of 22.5%, 22.2% respectively.