The Synthesis Of Linear/Hyperbranched Fluorinated Polymers And Study On The Properties Of Their UV Cured Films

The present thesis was aimed on the synthesis of perfluoroalkyl phosphate acrylates, fluorinated hyperbranched polyester acrylates and fluorinated hyperbranched polyesters, and the study on their photopolymerization behaviors, water and oil repellency, and surface composition of the UV cured film. The detailed outline is elaborated as follows:The perfluoroalkyl phosphate acrylates (PFPAⅠand PFPAⅡ) for UV-curing systems were synthesized and characterized with 1H NMR and FTIR spectroscopic analysis. The photopolymerization behavior was investigated by using photo-DSC analysis, showing that both of the acrylates were photopolymerized quickly with a moderate final unsaturation conversion at the presence of a photoinitiator. The limiting oxygen indices of the UV-cured pure films were determined to be over 35. The surface properties of UV-cured urethane acrylate films added with PFPAs, were investigated by contact angle measurement, showing the increases from 92°to 110°for water and from 48°to 90°for 1-bromonaphthalene.Moreover, the surface tension decreased from 36.3 mN/m to 13.5 mN/m. The results showed that the addition of a small amount of PFPAⅠor PFPAⅡefficiently led to the increase in the contact angles, and the decrease in the surface tension. The XPS analysis confirmed that the UV cured film surface was enriched with fluorinated species.The fluorinated hyperbranched polyester acrylate (FHPA) was synthesized by modifying the hyperbranched polyester Boltorn H20 with fluorinated isocyanate, and characterized with 1H NMR and FTIR spectroscopic analysis. The water and oil wettability of the UV cured film with FHPA as an additive was investigated by contact angle measurement. The results showed that an extremely low concentration of FHPA, even below 0.1 wt%, resulted in efficient decrement of the surface tension of UV cured film to 10-15 mN/m, and thus makes the film highly hydrophobic and oleophobic. The film with FHPA addition was stable in acidic and neutral solutions, and still had good water repellency after immersion in a pH 1 solution for several days. The XPS analysis confirmed that the film surface was enriched with fluorinated species. Moreover, the molecule with the highest average number of perfluoroalkyl groups had the highest tendency to aggregate at the surface of the UV cured film.The commercial hyperbranched aliphatic polyols, Boltorn H20, H30 and H40, were modified by thioglycolic acid and hexafluorobutyl acrylate (HFBA) or dodecafluoroheptyl methacrylate (DFHMA) to prepare a series of fluorinated hyperbranched polyesters, TAH20-FHBA, TAH20-DFHMA, TAH30-DFMHMA, and TAH40-DFHMA. For comparison, a linear fluorinated polymer, poly(n-BMA-co-DFHMA), was synthesized through the copolymerization of n-butyl methacrylate (BMA) and DFHMA. The molecular structures were characterized by 1H NMR spectroscopic analysis. The synthesized polymers were incorporated into UV-curable formulations as additives, and exposed to a UV lamp at presence of a photoinitiator. After UV curing, the wettability of water and 1-bromonaphthalene to the films was investigated by contact angle measurement. The results showed that both the hydrophobicity and oleophobicity were greatly enhanced. Moreover, the fluorinated hyperbranched polymers possessed better water and oil repellency than the copolymer poly(n-BMA-co-DFHMA) at a very low concentration. The surface F/C ratio values of the cured films were detected by XPS analysis, and found that the film with TAH20-DFHMA showed the highest F/C ratio value, indicating the most efficient aggregation effect was obtained with TAH20-DFHMA at the film surface.The perfluoroalkyl phosphate acrylates were grafted onto the cotton fabric via y-ray irradiation to improve the hydrophobic and oleophobic properties. The change in chemical structure of grafted cotton fabric was detected by FTIR spectra and XPS analysis. The contact angles for water and sunflower oil were determined to be over 150°and 140°, respectively, after irradiated with a dose range of 471 to 5664 Gy. The flame retardancy of the fabric with the grafting ratio of over 13.0 wt%was improved, reaching to 24 compared with 18 of which before grafted, according to the Limiting Oxygen Index measurement. The microstructures of the fabric before and after grafted were observed by Scanning Electron Microscope, showing that the fiber of the textile were covered by the fluorinated polymers..