Study On The Structure And Properties Of Polyurethane Modified With Fluorinated Acrylate

Water-based polyurethane has a good cold tolerance, flexibility, resistance to organic solvents, etc. but poor water resistance. Copolymerization of the water-based polyurethane, can improve the performance of polyurethane. polyacrylate has good water resistance, chemical resistance and weather resistance.Therefore, The composite latex was prepared by the combination of polyurethane and polyacrylate, Not only it has good properties of the original polyurethane, but also it increases the water resistance, UV resistance and aging properties of the film. It improved the performance of the emulsion significantly.The hydroxyl-terminated acrylate copolymer was prepared by solution free radical polymerization. The molecular weight was controlled by changing the amount of chain-transfer SHCH2CH2OH. A series of different molecular weight copolymer were synthesized. The structure of the copolymer was characterized by FT-IR,1H-NMR test. Intrinsic viscosity of the copolymer was measured. It Show that the molecular weight of the copolymer decreases with the increasing of the amount of the chain transfer agent. In addition, A second series of acrylic ester copolymers were prepared by changing the ratio of BA to G04. FT-IR,1H-NMR confirmed the structure of the copolymers. Testing by 13C-NMR, the sequence of the copolymer was analyzed. Coversion test show that the copolymers were obtained in high yield.The polyurethane copolymers modified by acrylate were synthesized through block copolymerization. Two different series of polyurethane-polyacrylate composite emulsion were prepared through PU modified with PA. Through the appearance, stability, and particle size testing, the performance of the emulsion is investigated to obtain the copolymer emulsion of better stability. By FT-IR test, the structure of the copolymer emulsion was characterized. It also evident that there is polymerization reaction between acrylate and polyurethane.By TEM test, core-shell latex particle morphology has been obtained. By DSC, TG test, the thermodynamic properties of copolymer film was investigated, results showed that:good compatibility of PA with PU, heat resistance of PU was not improved significantly. By the water-resistance, contact angle measurements showed that:water resistance of PUA was greatly improved than PU, with the increase of the molecular weight of PA, water resistance of PUA was enhanced; with the increase of the amount of fluoride monomer, surface water-resistance was enhanced. By EDX test, it confirmed the presence of the surface fluorine of the copolymer, and showed that the migration of fluorine was affected by its'structure and the outside conditions. By mechanical property testing, showing that there is not much changing comparing to PU, The modified PUA still have good mechanical properties.