▎ 摘　　要

NOVELTY - Aqueous polyurethane/dopamine-modified graphene nano composite latex comprises 30-50 wt.% oligomer polyatomic alcohol, 20-40 wt.% diisocyanate, 3-7 wt.% hydrophilic monomer, 2-8 wt.% hydroxide, and 0.01-30 wt.% dopamine-modified graphene. The aqueous polyurethane/dopamine-modified graphene nano composite latex is prepared by using improved Hummers method to prepare graphene oxide dispersion under condition of ice water bath, adding graphite, and concentrated sulfuric acid solution with proper proportion of sodium nitrate and potassium permanganate according to proportion. USE - Aqueous polyurethane/dopamine-modified graphene nano composite latex. ADVANTAGE - The aqueous polyurethane/dopamine-modified graphene nano composite latex has chemical resistance, corrosion resistance, has good application prospect in coating, effectively improves mechanical property, antistatic property, conductivity, electromagnetic shielding, and thermal conductivity. DETAILED DESCRIPTION - Aqueous polyurethane/dopamine-modified graphene nano composite latex comprises 30-50 wt.% oligomer polyatomic alcohol, 20-40 wt.% diisocyanate, 3-7 wt.% hydrophilic monomer, 2-8 wt.% hydroxide, and 0.01-30 wt.% dopamine-modified graphene. The aqueous polyurethane/dopamine-modified graphene nano composite latex is prepared by using improved Hummers method to prepare graphene oxide dispersion under condition of ice water bath, adding graphite, and concentrated sulfuric acid solution with proper proportion of sodium nitrate and potassium permanganate according to proportion, uniformly mixing and reacting for 9-12 hours, slowly adding distilled water, stirring for 1-2 hours, adding 85 wt.% hydrogen peroxide solution to change light yellow color and not generate bubble, centrifuging to obtain supernatant, which pH is neutral, dialyzing and then dispersing in mixed solution of water and dimethylformamide (DMF), using ultrasonic cell crusher to dispersing treatment to obtain oxidized graphene dispersion under ice water bath. The mass ratio of graphene oxide dispersion, water and DMF is 1:1-1:10. The concentration of graphene oxide is 1-25mg/mL. The dopamine-modified graphene oxide dispersion is prepared by dispersing graphene oxide in Tris-hydrochloride (HCl) buffer solution (pH value is 8.5), adding proper amount of dopamine hydrochloride, reacting in oil bath at 40 degrees C for 24 hours, centrifuging to obtain supernatant, which pH is neutral, then dispersing in the mixed solution of water and DMF, ultrasonically dispersing to obtain final product. The mass ratio of dopamine hydrochloride, graphene oxide and mixed solution of water and DMF is 0.2:1-3:1. The proper proportion of diisocyanate, oligomer polyatomic alcohol and catalyst, reacted for 1-2 hours at 50 degrees C, then gradually temperature is raised to 60 degrees C, hydrophilic monomer is added and reacted for 6-8 hours at the temperature. The toluene-di-n-butyl amine method is used for measuring generating prepolymer of isocyanate group (NCO) content, and reaction temperature is reduced to 25 degrees C, hydroxide is added and reacted at 60 degrees C for 1-2 hours, then added into dopamine-modified graphene oxide dispersion in proper viscosity, high speed stirring and emulsified for 1 hour, reducing agent is added and reacted for 1 hour at 95 degrees C to obtain aqueous polyurethane/dopamine-modified graphene nanocomposite emulsion.