Synthesis Of Fluorinated Polyacrylate Emulsifier-Free Emulsion And Its Application As Textile Finishing Agent

Fluorinated polyacrylate has excellent properties such as water-oil repellency, dirt resistance, weather resistance and thermal stability. Fluorinated polyacrylate is used as textile finishing agent to improve water-oil repellency and dirt resistance of textile. Recently, fluorinated polyacrylate emulsion has been widely studied to meet requirements of environment and resource protection. However, the low molecular surfactants tend to desorb and migrate, resulting in the decrease of emulsion stability, adhesion, water repellency and oil repellency of fluorinated polyacrylate film. Emulsifier-free emulsion polymerization is expected to overcome such disadvantages. In this thesis, we have studied synthesis, properties and application of fluorinated polyacrylate emulsifier-free emulsion by RAFT emulsifier-free emulsion polymerization. The main results obtained are as follows.Fluorinated polyacrylate emulsifier-free emulsion was successfully synthesized via ab initio RAFT emulsion polymerization mediated by the poly(N,N-Dimethylaminoethylmethacrylate)-b-poly(hexafluorobutyl acrylate)(PDMAEMA-b-PHFBA) as polymeric surfactant. The molecular weight dristribution of PDMAEMA-b-PHFBA was 1.59, indicating the controllablity of polymerization. The critical micelle concentration(CMC) of PDMAEMA-b-PHFB A in aqueous solution was estimated to be 0.02 lg/L. Meanwhile, the surface tension could reduce to 27.90mN/m. In addition, the synthesis conditions of fluorinated polyacrylate emulsifier-free emulsion and latex film properties were investigated. The results showed that the fluorinated polyacrylate emulsifier-free emulsion and latex film with excellent performances was synthesized under the condition that the monomers were added dropwise, stirring speed was 250r/min, seed emulsion reaction temperature was 75℃, the amount of 2,2’-azobis (2-methyl propionamidine) dihydrochloride(AIBA) was 0.9%, mass ratio of BA to St was 6:4, the amount of PDMAEMA-b-PHFBA was 5%, the percentage of the PDMAEMA-b-PHFBA at the seed emulsion was 12%, the concentration of hydrochloride was 0.48×10-4mol/L, the amount of hydroxyethyl acrylate(HEA), hexafluorobutyl methacrylate(HFBMA), and methy acrylyl ethyl trimethyl ammonium chloride(DMC) was 2%,10%, and 1.5%, respectively. The latex particles, presented as spherical particles with narrow distribution, were characterized by DLS and TEM. The water repellency and thermal stability of the film increased with the increase of the amount of HFBMA. The fluorine preferentially migrated and concentrated at the film surface during annealing process.The water and diiodomethane contact angles of the fabrics finished with fluorinated polyacrylate emulsifier-free emulsion were investigated. The results showed that the water and diiodomethane contact angles of the finished fabrics increased as the amount of HFBMA increased. The water and diiodomethane contact angles of the finished fabrics were up to 137° and 92° when seed emulsion reaction temperature was 75℃, the amount of AIBA was 1.1%, the mass ratio of BA to St was 6:4, the amount of PDMAEMA-b-PHFBA was 2%, the percentage of the PDMAEMA-b-PHFBA at the seed emulsion was 12%, the concentration of hydrochloride was 0.54×10-4mol/L, the amount of HEA, HFBMA, and DMC was 3%,12%, and 2.25%, respectively. This indicated that the finished fabrics showed good waterproof and oilproof properties. The fiber surface was uniformly covered with a layer of fluorinated polyacrylate film. In addition, with the increase of DMC amount in the fluorinated polyacrylate, the antibacterial activities of finished fabrics increase gradually. When the content of DMC was 3.75%, antibacterial activities of finished fabrics against S. aureus and the E. coli were up to 90% and 94%, respectively.