Synthesis And Properties Of Waterborne Polyurethane Containing Siloxane And Fluorine

acrylate (PA) modified waterborne polyurethane (PU) is known as "third-generationwater-borne polyurethane". Due to the complementation of polyurethane and polyacrylate,WPUA combines the advantages of both PA and PU to improve the overall performance ofthe hybrid emulsions and their films. However, Acrylate-polyurethane (PUA) hybird emulsionexist deficiencies, such as the poor water resistance. In order to improve the water resistanceof WPUA films. the hydrophobic groups are introduce to WPUA hybrid emulsion. Moreover,Organic silicon polymer is a chemical compound with special structure. Silicone-containedgroups are easy to enrich on the surface during the film forming process, and provide themodified polymer films excellent water resistance and oil resistance, heat resistance and so on.Thus the viscosity of the system and the dosage of the solvent can be reduced, so theenvironmental pollution in the process of SiPUA emulsion application can be reduced.Organic fluorine polymer own some characteristics, such as fluorine atoms with small radius,high bonding energy of C-F bond and short bonding length, which provide thefluorine-containing polymer with superior stability, weathering resistance and corrosionresistance, and so on. Also, organic fluorine polymer are easy to move and enrich on thesurface during the film forming process. Therefore, It's a good way for surface modificationby intrducting the fluorine monomer and silicon monomer into WPUA emulsion.Siliconated polyurethane (SiPU) was synthesis by solution polymerization usingisophorone diisocyanate (IPDI), polypropylene glycol (PPG), hydroxypropyl terminatedpolydimethyl sioxane (PDMS), dimethylol propionic acid (DMPA) as hydrophilic chainextender,1,4-butanediol (BDO) and triethylamine (TEA) as neutralizing agent. A new type ofpolyurethane-acrylic hybrid emulsion containing siloxane and fluorine (FSiPUA) withcore-shell structure was synthesized by a seeded emulsion polymerization, in which the corephase consisting of butyl acrylate (BA), methyl methacrylate (MMA) and dodecafluoroheptylmethacrylate (DFMA), and the shell phase consisting of SiPU. The influence of the amount ofdimethylol propionic acid (DMPA), core-shell ratio, hydroxypropyl terminated polydimethylsioxane (PDMS) and fluorine-containing monomer DFMA on emulsion polymerization process and surface hydrophobic properties of the latex films was discussed. The structureand properties of the hybrid emulsion and its films were characterized by Fourier transforminfrared spectroscopy (FT-IR), contact angle (CA), transmission electron microscopy (TEM),thermogravimetry (TG) and differential scanning calorimetry (DSC) analysis. The surfacefree energy of latex films was estimated using classical liquid method. The results indicatethat both PDMS and DFMA are effectively involved in the emulsion copolymerization, andthe FSiPUA latex particles exist with obvious core-shell structure. When the amount ofcarboxyl is1.9%, and the core-shell ratio is5:5, SiPU and FSiPUA show a good appearance, ahigh monomer conversion rate, without gel phenomenon occurred in the process of emulsionpolymerization. The hydrophobicity of the FSiPUA emulsion films increase with theincreasing of the amount of PDMS and DFMA, When the mass fraction of PDMS and DFMAare5.5%and15%, respectively. the contact angle with deioned water is up to102.3°,Thesurface free energy is as low as21.67mN m-1. The thermal stability of the latex films wasimproved due to the induction of the PDMS and DFMA.