Study Of Adsorb Functional Fiber Which Based On Polyurethane

Lead ion is one of the five kinds of heavy metal ions which were most harmful to human body, it has great meaning to research high-performance adsorbent for removing lead ion from environment.With polyurethane as raw material, this study adopted wet spinning technology and electrostatic spinning technology to prepare polyurethane fibers modified by phytic acid, polyurethane fibers modified by CTS and lead ion imprinted polyurethane fibers respectively. The adsorptive property and specific selectivity of these fibers were investigated.This thesis mainly completed the following several aspects:(1) Preparation of polyurethane wet spinning fibers and study of it adsorption on Pb2+Taking phytic acid as modifier, phytic acid/PU fiber was prepared by wet spinning, explored the influence of coagulating bath, concentration of spinning solution, added content of phytic acid to fiber formability, and the influence factors of fiber adsorption on Pb2+. The results showed that, taking20%DMF solution as coagulation bath, mass ratio between phytic and PU at5:7, the modified fibers had a good adsorption on Pb2+. The fibers could get the saturation adsorption capacities73.25mg/g while pH of solution was6.0and temperature was20℃.(2)Preparation of polyurethane electrospinning nanofibers modified by phytic acid and study of it adsorption on Pb2+Taking phytic acid as modifier, phytic acid/PU nano-fibers were prepared by electro-spinning. Take SEM to analysis fiber morphology under different process. The results showed that, while mass ratio of phytic acid and PU was5:7, spinning voltage was23kV, accepted distance was18cm, extruded velocity was0.1mL/h, the average fiber diameter could get206nm. Dynamic contact angle results show that the modified hydrophilic fibers can be improved.Tale the above-described fiber membrane as adsorbent, measured before and after the changes in the concentration of lead ions adsorbed by EDTA titration, so as to explore the adsorption properties of the fiber membrane.The results showed that:Acid modified PU fiber membrane adsorption of Pb2+is an exothermic process, the adsorption capacity decreases with increasing temperature; the nanofiber membrane could get the saturation adsorption capacities136.36mg/g while pH of solution was6.0and temperature was20℃, the result was higher than wetting fibers73.25mg/g.(3)Preparation of grafting AA polyurethane wetting fibersTaking CTS dissolving in PU solution to get spinning solution, PU/CTS fibers were prepared by wet spinning; with PU/CTS wet spun fibers as a matrix, MDI surface activation, hydrolysis, fiber surface with amino; amino group with potassium persulfate oxidation-reduction system as the initiator, the grafted fiber surface AA; explore optimal conditions for grafting of AA. Infrared spectroscopy showed that AA successfully grafted onto the fiber surface; dynamic contact angle showed that the grafted hydrophilic fibers significantly improved AA; thermal gravimetric analysis showed that the thermal stability of the grafted fiber reinforced. While the mass ratio of CTS and PU was3:5, mass ratio of AA and activated fiber was10:1, reaction temperature was40℃, potassium persulfate amount of acrylic acid was1.4%,the biggest grafting rate59.10%could be obtained. Thermal stability of grafted fiber was enhanced, hydrophilic was improved significantly.(4) Preparation of Pb2+imprinted polyurethane wet spinning fiber and study of its adsorption capacity and specific recognition on Pb2+Taking AA grafted fiber as raw material, EDC and NHS after surface modification be modified chitosan; adopting molecular imprinting technique, with lead ions as the template, epichlorohydrin as a crosslinking agent, lead ion imprinted obtained modified polyurethane fibers were prepared, its adsorption properties of lead ions was studied. The fiber could get the saturation adsorption capacities75.1mg/g while pH of solution was6.0-7.0and temperature was20℃. Taking flame atomic absorption spectrophotometry to test the specific selectivity of imprinted fiber and non-imprinted fiber. The result showed that, the imprinted fiber had a good specific selectivity for Pb2+, the relative selective coefficients for Cu2+、Cd were2.72、6.06, relatively.(5)Preparation of grafting AA polyurethane elecstro-spinning nano-fibersTaking a mixed solution of N, N-dimethylformamide and tetrahydrofuran (1:1weight ratio) as solvent, preparation of spinning liquid polyurethane solution, polyurethane electro-spinning nano-fibers were prepared. SEM analysis morphology of the fibers under different conditions. The results showed that,while spinning solution concentration was6%, spinning voltage was23kv, accepted distance was18cm, extruded velocity was0.1mL/h, the average fiber diameter could get507nm.In PU electrospun fiber membrane matrix, its surface activation with MDI, hydrolysis, adding potassium persulfate, potassium persulfate and the use of fiber surface oxidation of the amino form-reduction system, causing the fiber surface grafting AA, explore optimal grafting conditions. Scanning electron microscopy, infrared analysis showed that, AA successfully grafted onto the fiber surface; dynamic contact angle results showed improved grafted hydrophilic fibers. While mass ratio of AA and activated fiber was11:1, reaction temperature was40℃, potassium persulfate amount of acrylic acid was1.3%,the biggest grafting rate57.85%could be obtained. The result was inferior to wet spinning fiber59.10%.(6)Preparation of Pb2+imprinted polyurethane electrospinning nanofiber and study of its adsorption capacity and specific recognition on Pb2+On the basis of grafting AA, EDC and NHS carried out its rear surface modified chitosan modified; combined with molecular imprinting technique to lead ions as the template, epichlorohydrin as a crosslinking agent, Pb2+imprinted polyurethane electrospinning nanofibers were prepared, the imprinted membrane adsorption of Pb2+was explored. The fiber could get the saturation adsorption capacities103.8mg/g after3h while pH of solution was6.0-7.0and temperature was20℃. The result was higher than imprinted wet spinning fiber75.1mg/g.Taking flame atomic absorption spectrophotometry to test the specific selectivity of imprinted fiber and non-imprinted fiber. The result showed that, the imprinted fiber had a good specific selectivity for Pb, the relative selective coefficients for Cu2+、Cd2+were5.04,3.91relatively.