Study And Application Of Hydrophilic/Hydrophobic Surface Materials By Carbene Modification

With the rapid development of science and technology productivity and the continuous improvement of people's living standards,water pollution caused by oil production industry leakage and chemical industry discharge is also increasingly serious.An important cause of environmental water pollution is that oil and water are mixed and difficult to separate,which will lead to a large area of death of aquatic organisms,as well as safety problems such as combustion and fire.Therefore,it is very urgent to develop oil-water separation materials and technologies.In this paper,a series of alkyl diazomethanes and alkoxy diazomethanes have been prepared by suitable molecular design.Through the insertion reaction of diaryl carbene,different alkyl chain and alkoxy chain were introduced on the surface of cotton cloth,which made the modified cotton cloth have different hydrophilic/hydrophobic effect.When alkyl and alkoxy diazomethane are modified on the surface of cotton cloth in different proportion,the modified cotton cloth with controllable wettability can be obtained.This has a good prospect in the field of oil-water separation.The specific research is as follows:First of all,starting from the phenomenon of oleophillic/hydrophobicity in nature,this paper introduces the basic theory of surface infiltration,including Yang's equation,Wenzel model and Cassie baser model.Oil-water separation materials are summarized from five aspects: hydrophobic and oleophillic oil filtration materials,hydrophobic and oleophillic oil absorption materials,hydrophilic and underwater oleophobic materials,combination of hydrophillicuty and oleophobicity and intelligent smart hydrophobic switch separation materials and research progress.The preparation methods,chemical reactions and the development of carbene in the field of surface modification were reviewed.On this basis,the research idea of this paper is put forward: combine carbene surface modification technology with hydrophilic/hydrophobic groups,change the wettability of the material surface by changing the chemical composition of the surface,and prepare oil-water separation materials with selective hydrophobicity and selective oil drainage.Then a series of different diaryl diazomethanes were synthesized by reasonable molecular design.Firstly,diazomethane with long chain alkyl was synthesized from 4,4'-dihydroxybenzophenone by Williamson synthesis,hydrazone reduction and manganese oxide oxidation.Then diazomethane with long chain alkoxy group was obtained from sulfoxide chloride and tetraethylene glycol monomethyl ether by halogen substitution and so on.As the precursor of carbene,carbene can be rapidly generated by strong light or heating.Finally,the hydrophobic cotton cloth or hydrophilic cotton cloth was prepared by the insertion reaction of carbene and the covalent bond of hydroxyl or C-C bond on the cotton cloth.According to SEM,EDS,XPS,elemental analysis and other tests,it can be seen that the surface morphology and elements of cotton cloth have obvious changes,which proves that all the carbine has been modified to the surface of cotton cloth.The water contact angle of the modified cotton cloth also has obvious changes.The water contact Angle of the modified cotton cloth is also significantly changed,and the contact angle varies from 10° to 157°.The results of oil-water separation test show that the separation effect is 99% for the first time and 97% for the lowest efficiency after 30 cycles,which shows that carbene modified cotton cloth has good service life and separation efficiency.Finally,the cotton cloth with water contact angle controllable in a certain range was prepared by modifying the dodecyl diazomethane and alkoxy diazomethane to the surface in different proportions.This provides a new idea for the research of wettability field,and has a very good application prospect in the preparation of wettability controllable coating.In conclusion,the modified cotton cloth with different degree of hydrophilicity / hydrophobicity was prepared.Two main rules are obtained:(1)when the modified compounds are alkyl diazomethanes,with the increase of the length of the alkyl chain,the size of the contact angle has been increasing.(2)When different proportion of dodecyl alkyl diazomethane and alkoxy diazomethane are modified on the surface of cotton cloth,it can be seen that with the decrease of the proportion of alkyl diazomethane,the contact angle will decrease obviously.In other words,this method can make wettability controllable,rather than a simple hydrophilic / hydrophobic switch,which can be more detailed in the preparation of intelligent controllable materials and interfaces,which also proves the feasibility and effectiveness of carbene modified surface to change its wettability.