Research And Application Of Hydrophobic Modification Based On Polyphenol Surface Deposition

Oil spills and pollution by organic solvents have caused great damage to the natural environment,and oil-absorbing materials are often used to deal with oil-water pollutants.There are many kinds of oil absorbing materials,including zeolite,activated carbon,clay,straw,fiber,sponge and so on.As a common oil-absorbing material,sponge has the advantages of light weight,large oil-absorbing ratio and good circulation performance,but it also has the disadvantages of poor oil-water selective adsorption performance.Therefore,it is necessary to modify the surface of sponge to improve its oil-water selectivity.The hydrophobic modification of sponge mainly starts from reducing surface energy and increasing surface roughness.In the existing studies on sponge modification,simple impregnation,graft polymerization,surface assembly and other methods are often used to change the surface composition of sponge to reduce the surface energy,or modification of inorganic nanoparticles,chemical polymerization and other methods to change the surface morphology of sponge to improve its hydrophobic performance.Dopamine has good adhesion to most substrates.In existing studies,the adhesion,deposition and further reaction of residual functional groups of dopamine are often used to achieve sponge modification by introducing hydrophobic substances,but there are few studies on the regulation of sponge surface roughness.The reaction of dopamine requires oxygen,usually 10-24 h,which takes a long time and is affected by the thickness of reaction liquid(oxygen content),so the modification is not easy to be uniform.In addition,the high price of dopamine is not conducive to actual mass production.Graphene oxide is often used as filler to blend with other substrates to prepare composites to improve the air tightness of the material.At present,the higher price of graphene oxide with fewer lamellar layers is not conducive to the composite of cheaper PE materials,while graphene oxide with lower commercial price generally has thick lamellar layers.In addition,graphene oxide contains large polar oxygen-containing groups,which are difficult to disperse evenly in organic systems.Therefore,hydrophobic modification of graphene oxide is needed to improve its dispersion in organic solvents.At present,most of the research on the modification of graphene oxide by polyphenols is through the deposition of polyphenols on the surface of graphene oxide to form a shell,and as a reaction platform to modify the hydrophobic substances on the surface morphology of graphene oxide,the impact of the thickness of the lamellar and industrial applications of graphene oxide are less studied.In view of the problems in the study of dopamine modified sponge,in this paper,using antioxidant promotes the dopamine response,shorten the reaction time,the dopamine deposition on the surface of the sponge,at the same time,the formation of dense particle layer,surface morphology,increase the surface roughness,and then provides the active group for subsequent modification,reaction with long chain alkyl amine,the introduction of low surface energy material,Improve the hydrophobic and oil-absorbing properties of sponge;In order to solve the problem of uneven modification caused by excessive thickness of the reaction solution,enlarging experiment was carried out on the basis of small test,changing the technological conditions,soaking adsorption solution,and then reacting in the air.In order to reduce the production cost,the hydrophobic modification of dopamine was replaced by catechol and tetraethylenepentamine.In view of the problems in the study of dopamine-modified graphene oxide,the commercial graphene oxide with thick lamella was used as the base for the modification to reduce the cost and facilitate the industrial application.A simple and effective "one-step" method was used to deposit dopamine on the surface of graphene oxide and react with octadecylamine at the same time to regulate the surface morphology and lamellar thickness of graphene oxide and improve the hydrophobic properties of graphene oxide.This paper mainly does the following work:1.Hydrophobic modification of sponge surface by rapid deposition of dopamine particlesBy adding sodium iodate,dopamine was rapidly deposited on the surface of melamine sponge to form a dense particle layer,which improved the roughness and provided the active group.Octadecylamine was modified on the surface of the sponge by reacting with the active group to perform hydrophobic modification on the sponge.The optimum reaction conditions were investigated by changing the surface roughness and contact Angle.The properties of the modified sponge,such as hydrophobicity and oil absorption,were investigated.Based on the small-scale test results,the hydrophobic modification of large size sponge was carried out through the optimization of technology.The properties of the large size modified sponge were tested and applied to the development of drilling coring tools.2.Hydrophobic modification of sponge surface by rapid deposition of catechol-tetraethylenepentamine particlesThe cheap catecheol and tetraethylenepentamine were used to replace the expensive dopamine.By the reaction of catecheol and tetraethylenepentamine,particle layer was formed on the surface of melamine sponge to increase the roughness.Then,octadecylamine was introduced to modify the sponge.The effects of different reaction conditions on the surface roughness and hydrophobic properties of modified sponges were investigated and the optimum conditions were optimized.The oil absorption,thermal stability and corrosion resistance of the modified sponge were investigated.3.Surface hydrophobic modification of graphene oxide by dopamine depositionA simple one-step process was used to modify the surface of graphene oxide with dopamine and octadecylamine through dopamine self-polymerization and the reaction of dopamine and octadecylamine to improve its hydrophobic properties and dispersion in organic solvents.The effects of dopamine concentration on the surface morphology,hydrophobic properties and dispersion properties of graphene oxide were investigated.The thermal stability of graphene oxide was tested and applied to improve the air tightness of high-density polyethylene.