Research On The Preparation Of Superhydrophobic Polyurethane Sponge And The Application In Oil/Water Separation

With the rapid development of the modern petrochemical industry,oil spill accidents have become a common occurrence,which greatly increases the amount of discharged industrial oily sewage,and poses a huge threat to the ecological environment,human health,and social economy.Traditional oil-water separation methods and materials have problems such as low efficiency,high energy consumption,poor durability,limited emergency response capacity and so on.Aiming at these problems,this thesis uses commercial polyurethane sponge as a porous substrate to prepare super-hydrophobic and super-lipophilic materials by in-situ growth method,dip coating-curing method and solution reaction to achieve rapid oil-water separation.The preparation method has the characteristics of simple,green,high efficiency,fast responsiveness,and has huge industrial application potential.The main research contents and conclusions of the thesis are as follows:The octadecyltrichlorosilane(OTS)was grafted onto the surface of the oxidized polyurethane sponge by the in-situ growth method to prepare a superhydrophobic polyurethane sponge.To be more specific,a polysiloxane hydrophobic layer was uniformly grown on the surface of the prepared sponge.Moreover,the edge of the sponge skeleton presents a wavy structure,and the surface forms a micro-nano rough structure.When the OTS concentration is1.0 wt%,the water contact angle(WCA)of the sponge can reach 154.8°.After being immersed in solutions of different p H values for 24 h,100 cycles of friction and heat treatment at different temperatures,the water contact angle of the material surface can still be maintained above 150°.Besides,the adsorption capacity for different oils and organic solvents can reach 21 to 62 times of its own mass.After 100 times of repeated extrusion and oil absorption,it can still maintain high adsorption performance,and its water contact angle can also be maintained above 147°.At the same time,the continuous oil-water separation efficiency of different oils and organic solvents is as high as 93%,and the separation efficiency of the emulsion prepared with 0.1 wt%Span 80 is as high as 99.66%.The surface of the four-needle zinc oxide whisker(T-Zn Ow)was hydrophobized by the sol-gel method,and then was loaded onto the surface of the polyurethane sponge by the dip coating-curing method to prepare a superhydrophobic polyurethane sponge with photodegradation function.When the mass ratio of the super-hydrophobic tetrapod-shaped zinc oxide whiskers(ST-Zn Ow)and polydimethylsiloxane(PDMS)is 0.5:1,the water contact angle of the sponge is 157.5°.After soaking in acid-base corrosion solution,rubbing with sandpaper and heat treatment,the sponge can still maintain excellent hydrophobic properties.The adsorption capacity for different oils and organic solvents is 12 to 35 times of its own mass.After repeated extrusion-oil absorption experiments,it can still maintain its good adsorption capacity and high hydrophobicity,showing excellent reusability.The continuous oil-water separation efficiency of the material for different oils and organic solvents is above 95%,and the separation efficiency for the emulsion prepared with 0.1 wt% Span 80 content of is 99.84%.At the same time,the prepared material can degrade the organic dye methylene blue under ultraviolet light,and the degradation rate can reache 99.35%,showing excellent potential for degrading organic pollutants.Based on the chemical reaction strategy of dopamine,with polydopamine(PDA)as the secondary functional modification platform,aminopropyltrimethoxysilane(APTMS)as the crosslinking agent,octadecyltrimethoxysilane(ODTMS)as the hydrophobic modification platform,and ammonium persulfate as the oxidizing agent,a green and sustainable superhydrophobic polyurethane sponge is prepared through solution reaction.After codeposition and coating of PDA,APTMS and ODTMS,a multi-level rough structure is formed on the surface of the sponge,and the water contact angle reaches 153.7°.The sponge can maintain high hydrophobicity after being immersed in an acid-base solution with a p H value of1to11,but a solution of p H=13 is easy to destroy the intermolecular force of PDA and affect the hydrophobic structure of the sponge surface.Due to the strong adhesion and high temperature resistance of PDA,the sponge can maintain excellent hydrophobic properties after being rubbed by sandpaper and treated at high temperature.At the same time,the sponge has higher adsorption performance(the adsorption capacity is 25 to 96 times of its own mass)and excellent reusability.Additionally,the continuous oil-water separation efficiency for different oils and organic solvents is above 96%.The separation efficiency of the emulsion prepared by 0.1 wt%Span80 is 99.81%,and the material exhibits excellent oil-water separation performance and emulsion separation performance,which has great potential in practical applications.