Study On The Preparation Of Functional Nanofibers Based On The ATRP Technology And Their Applications

It is well-known that atom transfer radical polymerization(ATRP)is a controlled/living polymerization method.The ATRP method has often been adopted for making linear polymer chains/brushes with controlledmolecular lengths/weights since the propagation centers do not undergo chain termination and/or chain transfer during polymerization,and thus the molecular weights/lengths increase linearly with the conversion of monomers.Therefore,this method is widely used in the field of surface modification at present.Electrospun nanofibers with specific surface area and porosity,good structure with high and characteristics of modified,so it can be widely used in the field of industrial materials,biomedical and mechanical manufacturing,etc..In this paper,polyacrylonitrile(PAN)and polyurethane(PU)/regenerated cellulose(RC)nanofibers were prepared by electrospinning and followed modified with ATRP technique,then the nanofibers were endowed with good functionality in the field of metal ion adsorption and immobilization of enzymes,while the functional groups such as carboxyl,hydroxyl and carbonyl groups were grafted on the surface of the nanofibers.AOPAN-poly(HEMA)and AOPAN-poly(AA)nanofibers were prepared by amidoxime and ATRP modification while choosing 2-hydroxyethyl methacrylate(HEMA)and acrylic acid as the monomers separately.The morphology of the nanofibers was characterized by SEM)and FTIR.The results showed that:the surface of the modified nanofiber has obviously rough while the diameter of electrospun PAN nanofibers was uniform,but it still maintain good fiber morphology,in addition,a certain number of functional groups were successfully grafted on the surface of nanofibers.Then the adsorption capabilities of the AOPAN-poly(HEMA)and AOPAN-poly(AA)nanofibers were evaluated by inductive coupling plasma emission spectrograph(ICP-AES).The results show that:the adsorption capacity of AOPAN-poly(HEMA)nanofibers to Cu(II),Ni(II),Cd(II)and Co(II)ions is in the order of Cu(II)>Ni(II)>Cd(II)>Co(II).The adsorption ability of AOPAN-poly(AA)nanofibers to four metal ions of Fe(IHI),Cu(II),Cd(II)and Cr(II)is decreases gradually.In this study,the adsorption isotherms were established according to the adsorption capacity of metal ions at different initial concentrations by functional nanofibers.The experimental data were fitted by isothermal model,it is confirmed that the adsorption of metal ions by the above two functional nanofibers is monolayer adsorption.The AOPAN-poly(HEMA)-Cu(?)nanofibers were explored for laccase immobilization by the method of ion coordination.The optimum reaction time of ATRP was investigated by the amount of laccase immobilization.At the same time,the activity of immobilized laccase and free laccase was compared by degradation of guaiacol under the same conditions.The study showed that:the optimum reaction time was 4 hours,and the immobilized laccase has better temperature stability,pH stability.The PU/RC-poly(HEMA)composite nanofibers were prepared byATRP modification with hydroxyethyl methacrylate(HEMA)as graft monomer after the PU/RC composite nanofibers were prepared.Fe(?)-PU/RC-poly(HEMA)composite nanofibers were explored as the novel support for laccase immobilization after prepared by adsorption reaction with iron ion solution,the difference between immobilized laccase and free laccase was also investigated.The results showed that the optimal fixation time of laccase was 12 hours,and The immobilized laccase showed better temperature stability,pH stability,storage stability and reuse performance compared with that of free laccase.