Study On Water Whitening Of Castor Oil-Based Polyurethane Acrylate Hybrid Latex Film

The long-term exposure to water in a wet environment tends to cause water whitening,resulting in aging of the polymer materials,and problems such as blistering,cracking,chalking,falling off,watermarking,and efflorescence of the coating film,affecting the decorative and protective properties of the coating film.Therefore,it is necessary to study the water whitening of polymers.Glycidyl tertiary carbonate(E10p),castor oil,isophorone diisocyanate(IPDI),methyl methacrylate(MMA),butyl acrylate(BA)and vinyl versatate(V10)as the main raw materials The castor oil-based waterborne polyurethane and castor oil-based urethane acrylate composite emulsions were prepared.The water whitening mechanism of the latex film and the mechanical properties of the water whitening film were studied.The paper has carried out research on the following three parts.In this paper,castor oil-based waterborne polyurethane and castor oil based composite emulsions were prepared with glycidyl tertiary carbonate,castor oil,isophorone diisocyanate,methyl methacrylate,butyl acrylate and tert-vinyl carbonate as the main raw materials.The water whitening mechanism of this system latex film and the mechanical properties of water whitening film were studied.The paper mainly studies the following three aspects.?.Study on water whitening of modified c polyurethane coatingsThe EPUD was synthesized using castor oil,isophorone diisocyanate(IPDI),dimethylol propionic acid(DMPA)and E10 p as the main raw materials.The basic properties of the latex film were analyzed by infrared spectroscopy and thermogravimetry.Investigated the water bleaching influencing factors of E10 p system latex film.Infrared characterization demonstrated the successful preparation of the EPUD emulsion.According to the UV spectroscopic characterization,as the water soaking time prolongs,the light transmittance of the film becomes smaller and smaller,which proves that the cause of the water whitening of the latex film is the existence of light scattering in the water film,and the size of the water area is immersed in water.The prolongation of time and the increase of temperature increase the degree of water bleaching of the latex film.The mechanical properties of the water-whitening latex film were characterized.The storage modulus was related to the degree of water whitening.The more serious the degree of water whitening,the higher the storage modulus of the latex film.The increase of E10 p content reduces the amount of bound water in the latex film.?.Study on water whitening of polyurethane-acrylate latex filmA castor oil based polyurethane dispersion was synthesized using castor oil,IPDI,and DMPA as starting materials.The prepared PUD was used as seed emulsion,and MMA and BA radical polymerization was carried out by semi-continuous addition.A PUA composite emulsion was prepared.By UV spectrophotometer,DMA,DSC and other analytical means that when the PUA coating film is immersed in water,water will enter the PUA latex film will produce water,the film will produce water whitening;water bleaching phenomenon with the temperature of the infusion increases Increasing,when the immersion temperature is much lower than the glass transition temperature,its storage modulus and Tg remain basically unchanged,and the film does not produce water whitening.When the film is immersed in water for 24 h at room temperature,the film will produce slight water whitening,and its storage modulus and Tg will decrease.When it is dried again,the latex film can restore the original transparency;when the film is above the glass transition When the temperature is soaked for 24 h,its storage modulus decreases,Tg increases,and severe water bleaching occurs.?.Study on water whitening of V10 modified polyurethane-acrylic latex filmThe preparation of VPUA was based on WPUA and vinyl versatate was introduced to study the effect of the composite emulsion and its latex film properties.The infrared characterization demonstrated the successful preparation of the emulsion.Dynamic mechanical analysis of the storage modulus changes of water-whitening films at different water immersion temperatures shows that,as the water soaking temperature increases,the water-whitening coating storage modulus and glass transition temperature are all relative to the dry film.Some decrease,and the more obvious the decrease with increasing temperature.DSC studies have shown that the introduction of V10 effectively reduces the presence of free water in the membrane,and as the V10 content increases,the amount of bound water in the membrane can be further reduced.