The Study On Nano-Silica Acrylate Soap-Free Emulsion Prepartion And Its Application In Caoting

As a result of the existence of common emulsifiers in emulsion polymerization, not only seriously affected the performances of the emulsion such as stability but slao caused serious pollution to the environment, soap-free emulsion polymerization arised at the historic moment, becoming one of the forefront subjects in polymer science and materials. The acrylate soap-free emulsion and nano-silica acrylate soap-free emulsion were prepared by means of semi-continuous seeded emulsion polymerization and the application of these two kinds of soap-free emulsion in the coating was studied.We screened the species and the amount of reactive emulsifiers, produced water-based intumescent fire-retardant coatings with the emulsions and tested the water resistance and fire-retardant performanceThe acrylate soap-free emulsion was prepared by means of semi-continuous seeded emulsion polymerization using butyl acrylate (BA), styrene (St), methyl methacrylate (MMA) as monomer and allyloxy hydroxypropyl sulfonate sodium (HAPS), allyloxy nonylphenol polyoxyethylene (10) ether sulfate (DNS-86), allyloxy nonylphcnoxy poly (cthylcncoxy) (10) cthcr (ANPEO10) and ANPEO10-P1 as the reactive emulsifier single and composite mixtured. Effect of the type and amount of reactive emulsifier on properties of emulsion were analyzed. The results showed that the emulsion has the best stabilities in chemical, heat and storage when only using DNS-86. As the content of DNS-86 keeps increasing, the solid content and monomer conversion of emulsion increases first then starts to drop. When the content of DNS-86 is 2.5%, the solid content is 40.6% and monomer conversion of emulsion is 95.7%, all are the biggest. Because of DNS-86 is esay to homopolymerization, the particle size of emulsion increases first then starts to drop as the content of DNS-86 keeps increasing, not only the average particle size and the PDI of emulsion is the smallest, but slao water contact angle of the corresponding film is the smallest when the content of DNS-86 is 3%.So when the content of DNS-86 is 2.5%～3%, the comprehensive performance of emulsion is the optimal:the solid content and monomer conversion are the biggest, the average particle size, dispersion index and water contact angle of the corresponding film are the smallest the performances of emulsion are perfect.Chemical structure of the emulsion was characterized by fourier transform infrared spectroscopy (FT-IR) and the particle size was characterized by laser particle size instrument. The results showed that the polymerization reaction is completely, the particle size is uniform, the emulsion has smaller particle size and narrow distribution, the average particle size is 70.76 nm, PDI is 0.052.Nano-silica acrylate soap-free emulsion was prepared using DNS-86 as reactive emulsifier adding nano silica sol 2034DI and the effect of the dosage of the nano silicon sol on the properties of the emulsion was studied.The results showed that the quantity of condensate and the emulsion condensation rate increases gradually the stability of the emulsion falls as the amount of nano silicon sol increasing. As the content of the nano silicon sol keeps increasing, the solid content and monomer conversion of emulsion increases first then starts to drop. When the content of the nano silicon sol is 3%, the solid content is 43.8% and monomer conversion of emulsion is 96.8%, all are the biggest.Emulsion has narrow particle size distribution, the particle size and PDI increase as silica content increasing, the average particle size is under 100 nm when the content of nano silica sol is lower than 2%. through water absorption and contact Angle test, ww found that the addition of nano silicon sol significantly improves the water resistant performance of latex film.SEM analysis of nano-silica acrylate soap-free emulsion shows that the latex particle looks like the neat ball, most inorganic silica particles adsorbed on the surface of latex particle or was enshrouded inside, the particles distribute evenly and the particle size is around 100 nm. Chemical structure of the emulsion was characterized by fourier transform infrared spectroscopy (FT-IR) comparing with acrylate soap-free emulsion shows that the silicon sol took part in the copolymerization combining with polyacrylate emulsion grainsin the form of chemical bonds.GPC analysis of nano-silica acrylate soap-free emulsion, acrylate soap-free emulsion and acrylate emulsion shows that the initial decomposition temperature of nano-silica acrylate soap-free emulsion is 386℃ which is higher than that of acrylate soap-free emulsion, and the initial decomposition temperature of acrylate emulsion is 354℃ which is the lowest. Nano-silica acrylate soap-free emulsion more accords with the requirement of water-based intumescent fire-retardant coatingsThe performances about water resistance and flame retardation property of the water-based intumescent fire-retardant coatings prepared by presented nano-silica acrylate soap-free emulsion acrylate soap-free emulsion and commercial acrylic emulsion were compared through water resistance test and cone cabrimeter.The results shows that the water resistance of the water-based intumescent fire-retardant coatings prepared by presented nano-silica acrylate soap-free emulsion is the best with flat surface but the water resistance of the water-based intumescent fire-retardant coatings prepared by commercial acrylate emulsion is the worst with pinhole on the surface.Quality loss, carbonized volume, heat release rate(HRR), total heat release (THR) and smoke prodution rate(SPR) of the fire-retardant coatings were tested through cone calorimeter and the small chamber method test, the results show that the flame retardation property of inflating water-based fire retardant coating prepared by self-made nano-silica acrylate soap-free emulsion is superior to that by other emulsion and the flame retardation property of inflating water-based fire retardant coating prepared by acrylate soap-free emulsion is the worst.