Perfluoropolyether Grafted Copolymers:Synthesis And Its Application On Anti-Biofouling Coatings

In recent years, with the growing awareness of environmental protection, development of environmental benign anti-biofouling coatings has become an important research issue. The use of fluorinated polymer to achieve an antifouling coating with low surface energy is a hot topic. The low surface energy of fluorinated polymer is usually realized by introduction of long perfluoroalkyl chains which are difficult to be degraded in nature and have long-term accumulation in environment. Thus the development of fluoropolymer which can be used in environmental benign anti-biofouling and without long perfluoroalkyl chains, do have great significance.In this thesis, in stead of long perfluoroalkyl chain, perfluoropolyether modified styrene was designed and synthesized, which was then copolymerized with glycidyl methacrylate (GMA) and methyl methacrylate (MMA). Tridecyl alcohol polyoxyethylene (TO-5) and sodium dodecyl sulfate (SDS) were used as composite emulsifier, and ammonium persulfate (APS) was used as an initiator. The copolymerization condition including the ratio of emulsifiers, initiator concentration, reaction time and temperature range was optimized by analyzing the stability of emulsion and efficiency of polymerization. The best copolymerization condition:Pre-emulsification temperature is60℃, Pre-emulsification time is45min, Ultrasonic Time is20min, Pre-emulsification stirring speed is1000rpm, The polymerization temperature is60℃, Emulsifier ratio is5:1, Polymerization stirring speed is200rpm, The amount of initiator is0.5%of the total monomers, pre-emulsion was added dropwise over2h, The polymerization time is6h. Nano particle size analysis showed emulsion particles distributed between50-200nm, Emulsion stability analysis shows that the emulsion has good storage, centrifugal and dilution stability. The structure of perfluoropolyether grafted polymer was analyzed by infrared spectroscopy (FT-IR) and indicated the successful polymerization of the fluorinated monomers. Thermal gravimetric analysis (TG) shows perfluoropolyether grafted polymers have good thermal stability.The obtained emulsion of perfluoropolyether grafted copolymer was coated on glass plate or aluminum by a spin-coating machine. X-ray photoelectron spectroscopy (XPS) analysis indicated there is enrichment of fluorine atoms on the surface of copolymer coating. The water contact angle of the coating was increasing with the increasing of contents of fluorinated monomer till to reach125°. The results of anti-bacterial adhesion experiments indicated that the coating can restrain the growth of Gram-negative and positive bacterium. The diatoms adhesion test were conducted by the indoor siding experiments, and results shown that the perfluoropolyether grafted polymer coating had good diatom adhesion resistance. In addition, the perfluoropolyether graft polymer was combined with various additives to form a composite marine antifouling paint. The film thickness of the paint, adhesion ability and impact resistance were tested, and the results show that the film had an average thickness of54μm and good impact resistance, but the adhesion ability need to be improved. These results suggested that the developed perfluoropolyether-grafted copolymer with low surface energy has potential applications on anti-biofouling coatings.