Synthesis And Studies Of Fluorinated Water-borne Polyurethane-Polyacrylate Dispersions

Fluorinated polyurethane-polyacrylate(FPUA) dispersions had both theadvantages inherited from polyurethane(PU) materials such as excellent adhesion,regards toughness,mar-resistance,elongation, and the properties inherited frompolyacrylate(PA) materials such as hardness, weatherability, chemical resistance,gloss, and affinity to pigments. Whatmore, because of the fluorinated groups in mainchain and branch chain, FPUA also had excellent surface properties, such asexcellent environmental stability, water and oil repellency, chemical resistance andlow interracial free energy. Then FPUA had been considered the direction ofwater-bome polyurethane materials.In the first, the atmospheric temperature crosslinking fluorinated polyacrylateemulsions were synthesized by 1H,1H,7H -Dodecafluoroheptyl methacrylate as thefluorinated acrylate monomers, which contented ketone-hydrazide cross-linkingsystem. Then effects of fluorinated monomer on emulsions and films werediscussed. The result showed that the films of emulsions surface properties hadgotten a rapid progress only a few fluorinated monomers added, and the fluorinatedmonomer confined the ketone-hydrazide cross-linking.Then, the PU seed emulsions were prepared by IPDI, polyester diols, DMPA.Based on the PU seed emulsion, the fluorinated polyurethane-polyacrylate(FPUA)emulsions were prepared by two various technicses: monomer dropped technics andmonomer pre-emulsification technics. Then the best technics parameters werestudied such as temperature, stir speed, initiator, amount of acrylate monomersetc.By emulsions particles size and polymerization stability test, the various technicswere compared in polymerization step. The result showed that the emulsion particlesprepared by monomers pre-emulsification technics were smaller and had a thinnerdistribution than monomer dropped technicsBased on those studies,the structure and properties of films of FPUA emulsionswere studied by FT-IR, contact angle mearured, SEM and laser scattering instrument, also, the various technicses were compared. The results showed that there was a lotof fluorinated groups assembling units in the surface of FPUA films by IR and SEM.FPUA films showed better water and chemical resistance, socking resistance thanPU and common PUA films certificated by contact angle, water absorptionmeasured and mechanical property test. And it can be concluded that the filmsprepared by monomers pre-emulsification technics showed the best surfaceproperties.