| Polyacrylate emulsions are widely used in industrial,agricultural,and daily life due to their good film forming,weather resistance and environmental friendliness.However,polyacrylate emulsions are easily burned after formed film with heavy smoke and harmful substances,which threaten the safety of human life and property.Attapulgite(ATP)has a good flame retardancy prospect due to their large specific surface area,high thermal stability,excellent environmental protection and low cost.The organic phosphorus flame retardants have been widely used in the field of polymers flame retardant due to their nontoxic,smokeless,biocompatible and weather resistance.Therefore in this thesis,the ATP is modified and introduced into the acrylate matrix.At the same time,two novel reactive phosphate flame retardants with different amounts of phosphate--2-hydroxyethyl methacrylate mono(diphenylphosphonate)phosphate and 2-hydroxyethyl methacrylate bis(diphenylphosphonate)phosphate were designed and synthesized based on 2-hydroxyethyl methacrylate phosphate.And the polyacrylate emulsions containing phosphate were synthesized by seed emulsion polymerization.Then,the ATP/polyacrylate composite emulsions containing phosphorus were prepared by introducing ATP into polyacrylate emulsions containing phosphate via thiol-ene click reaction.Eventually,the composite emulsions were applied in leather finishing process,and the flame retardancy of the leathers was investigated.The main contents are listed as follows.The particle size of the ATP was successfully reduced by ball milling,acidification,and KH570 modification,and then double bonds were introduced on the surface.When the solvent was water,the ratio of ball/ATP was 5:1,ball milling at 400 r/min for 5 h,the diameter of ATP was 250 nm with an uniform distribution.When the concentration of HCl was 2 mol/L,and acidified at 60 °C for 6 h,the content of-OH exposed on the ATP surface was 4.806 mmol/g.The grafting double bond amount of ATP surface was 13.46 mg/g when 7% KH570 was added and reacted at 75 °C for 4 h.When the mass ratio of chlorodiphenyl phosphine,2-hydroxyethyl methacrylate phosphate,triethylamine and acetone were 1:1.2:1.5:3 and 1:0.6:3:6,respectively,2-hydroxyethyl methacrylate mono(diphenylphosphoryl)phosphate and 2-hydroxyethyl methacrylate bis(diphenylphosphoryl)phosphate were successfully prepared.ATP was introduced into the polyacrylate emulsion via thiol-ene click reaction.When the amount of ATP was 4%,the water vapor permeability,water resistance and mechanical properties of the film formed by the composite emulsion were improved,and the composite emulsion showed a best flame retardancy.The burning rate and MSD of the leather samples were reduced by 47.56% and 65.93%,respectively,and the LOI value was increased by 19.67%.The flame retardancy of the polyacrylate emulsions containing phosphate was closely related to the content of P,and the higher the percentage of P,the better the flame retardancy was.Among the three polyacrylate emulsions containing phosphate,the polyacrylate emulsions containing triphosphate showed the best flame retardancy.The burning rate and MSD of the leather samples were reduced by 85.37% and 80.70% respectively,and the LOI value was increased by 57.92%.The properties of the polyacrylate emulsions containing bisphosphate were the second,and the properties of the polyacrylate emulsions containing monophosphate were the worst.The introduction of ATP into the polyacrylate emulsions containing phosphate can further improve the water vapor permeability,water resistance and mechanical properties of the polyacrylate containing phosphate composite film.And the flame retardancy of the finished leather was improved due to the synergistic effect between ATP and phosphate.Among the three ATP/polyacrylate containing phosphate composite emulsions,the comprehensive properties of the ATP/polyacrylate containing triphosphate composite emulsion was the best,while the ATP/polyacrylate polyacrylate containing monophosphate composite emulsion was the worst. |
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