Preparation And Functionalization Of Environmental-friendly Two-component Waterborne Polyurethane Coating

The two-component waterborne polyurethane(2K WPU)coating has become a current research hotspot because of its excellent chemical resistance,weather resistance and wide range of soft and hard strength.However,most of the emulsifiers used in the synthesis process belong to alkylphenol compounds(APEO),which do not meet the current environmental protection requirements.In addition,the traditional2K WPU can no longer meet the needs of today's society with the increasing demand for 2K WPU coatings.In view of the above problems,this article uses semi-continuous seed emulsion polymerization process to prepare environmentally friendly hydroxyl acrylate emulsion,and on this basis,self-healing,and antibacterial and antistatic 2K WPU coatings were prepared,respectively.The specific research contents and conclusions are as follows:(1)Environmentally friendly hydroxyl acrylate emulsions using methyl methacrylate(MMA),acrylic acid(AA),butyl acrylate(BA)and hydroxyethyl methacrylate(HEMA)as comonomers were successfully prepared by the method of semi-continuous seed emulsion polymerization,and compounded with hydrophilic modified polyisocyanate(Bayhydur XP 2655)to obtain a 2K WPU coating.The effects of emulsifier type,emulsifier content,theoretical hydroxyl content,glass transition temperature(T_g)and–NCO/–OH(R)on emulsion and 2K WPU paint film were studied,and the weather resistance and chemical resistance of 2K WPU were also tested.The results showed that the 2K WPU film prepared with the emulsion from using SDS/TXT as emulsifier,emulsifier dosage of 2.5%,hydroxyl value of 100mg KOH/g,T_g of 10 ^oC,and polyisocyanate with NCO/OH of 1.4 exhibited the best performance.The 2K WPU paint film also had better chemical resistance,which can be applied to wood paint.(2)Polyvinyl alcohol/polyurea(PVA/PUA)hybrid microcapsules(MCs)loaded with isophorone diisocyanate(IPDI)as core materials were prepared via interfacial polymerization in an oil-in-water emulsion using different PVA as an emulsifier.The microencapsulation of IPDI was proved by Fourier transform infrared spectroscopy(FT-IR),scanning electron microscopy(SEM),and optical microscope(OM).The size of MCs decreased with the increase of alcoholysis degree and polymerization degree of PVA.The thermal property was assessed by thermo-gravimetric analysis(TGA).The results showed that the MCs prepared from PVA with the high polymerization degree or high alcoholysis degree had outstanding stability.Furthermore,the self-healing 2K WPU coating system containing MCs was prepared.The results showed that the self-healing 2K WPU coating displayed excellent self-healing performance and corrosion resistance,and the performance of self-repair2K WPU paint film was optimal when the addition of MC₁₇₉₉ was 9%.(3)The multifunctional polyaniline/copper/zirconia(PANI/Cu/Zr O₂)ternary nanocomposite was prepared by in-situ polymerization,and characterized by various testing methods.The effects of the nanocomposites on the antibacterial activity,antistatic properties and film properties of 2K WPU coatings were studied.The results show that PANI/Cu/Zr O₂ can significantly reduce the growth of Gram-positive and Gram-negative bacteria.The surface resistance of the 2K WPU coating with 5%ternary nanocomposite material was 4×10⁸?,which meets the industry standard for antistatic materials.The film properties and thermal properties of the modified 2K WPU coatings were improved in different degrees except for glossiness.