Polyaniline（PANI）has elicited the most interest due to its wide range of conductivity from insulating to metallicregime,unique redox tunability,good environmental stability,low cost,ease of synthesis,and promising applications in various fields,such as metallic corrosion protection,electromagnetic interference shielding,electrostatic discharge,sensors and actuators,and etc.Chiral PANI nanotubes with rectangular hollow interiors doped with （1S）-（+）-10-camphorsulfonic acid（D-CSA）as a chiral dopant were synthesized without aid of any surfactant.These nanotubes have 80 to 600 nm in outer diameter and 30 to 125 nm in wall thickness.The sructures of the synthesized samples were characterized by Fourier Transform Infrared spectroscopy（FTIR）, Ultraviolet-visible spectroscopies（UV-vis）and X-ray diffraction（XRD）.The four-probe conductivities of polyaniline naotubes doped with CSA were 10-4～100 S/cm.The effects of different synthesis conditions on the morphologies of polyaniline were analyzed,and the utmost conditions for synthesis of polyaniline nanostructures were as follows:the concentration of aniline was 0.05-0.1 mol/L;the molar ratios of CSA to ANI,and ammonium persulfate（APS）to ANI were about 1/8～1 and 1.2, respectly;the temperature was maintained in the range of 0～5℃and the reaction time was 15 h.Several kinds of polyaniline micro/nanostructures,such as tubes, fibers,networks,sheets,spheres and stars,were synthesized with the adjusting of reaction conditions,including the concentration of aniline,doping acid and oxidant, the the kind of doping acid and mixing speed,in the aqueous solution system.Nanostructured networks of PANI with conductivity of 10-2～10-1S/cm were synthesized via in situ polymerization of aniline using ferric chloride and APS as the co-oxidant through a “template-free” method.The further results showed that the ferric chloride played the roles of restraining the formation of PANI nanofibers and acting as both of oxidant and dopant at the same time,and the morphology and conductivity of the nanostructures could be controlled by adjusting the dosage of FeCl3 or the molar ratios of APS to FeCl3.The room temperature electromagnetic properties of polyaniline micro/nanotubes and nanostructured networks were studied.The tests of the eletromagnetic parameters of polyaniline nanostructures were evaluated,and it was found that polyaniline nanostructures exhibited dielectric loss and magnetic loss in the frequency range from 2 to 18 GHz.The electromagnetic absorption of polyaniline micro/nanostructures got well and the absorption peak shifted to low frequency with the ineases of molar ratios CSA to ANI.The maximal value of electromagnetic absorption was -19.1 dB at the frequency of 7.3 GHz.The dosage of FeCl3 was good for widening the frequency band and enhancing the reflectivity of polyzniline.
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The partially delaminated Stearic Acid Montmorillonite (STA-MMT) was synthesized, using alkaline Ca- montmorillonite and Stearic acid(STA) as raw materials on the condition of circumfluence, water diversion and dispersion in organic solvent. Single factor analysis was performed to investigate the influences of the factors, such as the reaction time, the amount of Stearic acid, the dosage of ethanol in dispersant, the amount of solvent, the droping temperature of the STA solution, the anion exchange capacity(AEC) of the alkaline Ca-montmorillonite, and the partical size of the alkaline Ca-montmorillonite, upon the ignition loss test of organic STA-MMT clay. The optimum preparation condition was achieved: add dropwise 60mL haxmethylene alkyl solution of Stearic acid(4.50g) into a large beaker, which contains 5.00g 0.076mm alkaline Ca-montmorillonite and 75mL mixed anhydrous solution at 50℃; the anhydrous solution is mixed by haxmethylene alkyl and absolute alcohol with volume ratio of 9: 1. The organic content of the prepared product was about 36.25%.With characterization tools such as XRD, FTIR, SEM, TG/ DTA and DTS, it is confirmed that: the Stearic acid anion is intercalated in the layer; the MMT is partially delaminated as the d-spacing enlarges; the dispersibility of STA-MMT reaches the scale of 300nm in the solvent of ethanol. In comparison with montmorillonite modified by cetyltrimethyl ammonium bromide, this partially delaminated Stearic acid montmorillonite has such merits like: better gel properties, larger surface area, smaller partical size and better dispersibility in most of organic dissolvents.Furthermore, using partially delaminated Stearic acid montmorillonite as a precursor, hydrophobic wax/stearic acid montmorillonite(wax/ STA-MMT) was prepared by introducing hydrophobic wax into the hydrophobic phased interlayer of partially delaminated Stearic acid montmorillonite. Through single-factor analysis, the optimum preparation condition was obtained: at 55℃, add 5.00g wax into a large beaker, which contains 3.00g STA-MMT and 200mL mixed anhydrous solution of haxmethylene alkyl and absolute alcohol ( V_A: V_H=1 : 9), then stir for thermostat reactions over 5 hours. The organic content of the prepared wax/STA-MMT is 71.55%, with 36.30% contributed by wax. XRD and DSC characterization means were used to study the structure and melting point of wax/STA-MMT. Through characterizations it is shown that good compatibility exists between STA-MMT and wax; meanwhile the melting point of wax increased by 60.7℃.
The natural macromolecular plant aloe vera L.with abundant source and cheap price was selected in this dissertation,and its flocculating performance was studied.Aloe gel,aloe polysaccharide and aloe powder were prepared,and the techniques of extraction of polysaccharides from aloe were studied.The contents of polysaccharide extracted by technique of alcoholic sedimentation at room temperature is 12.27%,highest ratio in this experiment.The flocculants prepared above were studied,and flocculation tests were carried on to kaolin simulated water sample prepared in the laboratory,with the method of stirring in beakers.The results indicate that aloe gel has the best flocculation effect to the sample prepared,and the removal ratio of turbidity is 99.08%,the optimum dosage of aloe gel is 0.75mg/L.The influence of different factors on flocculation effect of aloe gel were studied.Aloe gel has an extensive applicable pH range,the removal ratio of turbidity reach up to 92%when the pH of water sample is between 3 and 11,and the flocculation effect of aloe to high turbidity sample is better than to low turbidity sample.Compared with Fe2（SO4）3,PFS and PAM,the results indicate that aloe has a good flocculation effect,with characteristics of low dosage,high sedimentation velocity of flocs, thick floes.Compounded with Fe2（SO4）3,PFS and PAM separately,the results indicate that aloe compounded with Fe2（SO4）3 has the best effect,the removal ratio of turbidity is 99.12%, the optimum dosage of aloe is 1.68mg/L,and that of Fe2（SO4）3 is 20mg/L.Practical application of aloe was studied preliminarily,and the waste water of the YouYi River in Nanjing University of Science and Technology was treated.The results indicate that aloe has a good effect to the turbidity removal,and COD is also decreased.The removal ratio of turbidity is 93.44%and the removal ratio of COD is 64.34%,when aloe is compounded with Fe2（SO4）3 and the dosage of aloe gel is 4 mg/L,the dosage of Fe2（SO4）3 is 15mg/L.The stabilization of aloe gel was studied preliminarily.The results show that aloe gel can be preserved for 18 days when treated by potassium sorbate,citric acid,and adsorpted by active carbon,under the condition of refrigerated storage.The removal ratio of turbidity still keeps above 90%after stabilizing treatment and storaged for 14 days,which indicates that aloe keeps a good flocculation activity.
Carbon membranes are a new type of membrane materials featuring with molecular sieving property,which are mainly prepared by pyrolysis of polymers as precursors. Compared with polymeric membranes,carbon membranes have broad prospects in gas separation for possessing numerous advantages,such as high gas separation factor,good thermal resistance and chemical inertness.Carbon membranes can be divided into two categories:homogeneous and composite.The carbon composite membranes have attracted much attention recently because of their high mechanical strength.But the materials for the carbon membrane supports are usually high cost,which restricts the development and application of carbon composite membranes.Therefore,it is necessary to research and development low cost supports for the industrialization of carbon composite membranes.In this paper,coal based plate carbon membrane supports have been prepared by anthracite with blender and bituminous coal.The effect of processing parameters such as binder type,molding pressure,pre-oxidation temperature and pre-oxidation time on the performance of coal-based carbon membrane supports has been investigated,the technology route to prepare the coal-based carbon membrane supports has also been designed.The results show that the coal-based carbon membrane supports prepared with different metamorphic grade coals have different pore structure characteristics,the anthracite-based carbon membrane supports have a wide pore size distribution and a high gas permeation rate,but the largest pore diameter is larger,however,the bituminous coal-based carbon membrane supports have a narrow pore size distribution and the largest pore diameter is smaller.Hence the bituminous coal-based carbon membrane supports are more suitable to prepare carbon composite membranes.The plate carbon composite membranes have been prepared by spin-coating the PMDA-ODA polyamic acid（PAA）on the coal-based membrane supports.The effect of support property,spin coating technology,blending the surfactant in PAA and the pretreatment of the membrane support on the gas separation performances of carbon composite membranes has been investigated.Scanning electron microscope has also been employed to characterize the microstructure of the carbon composite membranes.The results indicate that the carbon composite membranes with high performances can be prepared by controlling spin coating technology.The surfactant showed the function of improving the composite between carbon plate and PAA,Carbon composite membranes with the suffactant additive reaching molecular sieving need only one time by spin-coating.The pre-immersing treatment on anthracite supports can greatly improve the gas permeation rate of the anthracite-based carbon composite membranes.For the bituminous coal-based carbon composite membranes,the selectivities of H2/N2,CO2/N2,O2/N2 are 94.3,18.3,10.2 respectively,and the selectivity for O2/N2 of air is 10.8 with the O2 permeation rate of 4.99×10-9mol·m·-2·S-1.Pa-1and the O2 concentration can reach 74.4%by one time enrichment.
Carbon membranes as novel porous inorganic membranes are usually prepared by carbonization of carbonaceous materials.Carbon membranes can be applied in many fields such as chemical production separation,gas separation,membrane reaction etc,because of their thermal and chemical stability in non-oxidizing atmosphere.However most of carbon membrane precursors are commercially expensive which may greatly limit the commercial application of carbon membranes.Therefore,it is necessary to search a low cost precursor to prepare carbon membranes.Coal has several advantages as the precursor for carbon membranes because of its low cost and aromatic structure,which is dominated by polycyclic as well as monocyclic aromatic ring system.Coal-based tubular carbon membranes have been prepared in carbon research laboratory of dalian university of technology since 1995.A Coal-based tubular carbon membrane with high flux,high porosity and narrow pore size distribution was prepared with CMC and anthracitic coal.However its low mechanical strength may greatly limit the commercial application of coal-based carbon membranes. Therefore,it is necessary to prepare a high strength coal-based tubular carbon membrane.In this paper,the procedure for producing high strength coal-based tubular carbon membranes with CMC as binder through mixing short carbon fibre,bituminous coal and anthracite coal was presented.TG,XRD and SEM were employed to study the reinforce mechanism.Effect of processing parameters such as the ratio of bituminous coal and short carbon fibre,carbonization temperature on the strength and pore structure of coal-based carbon membranes was investigated.The results show that bituminous coal and short carbon fibre can improve the strength of coal-based carbon membranes significantly.When the bituminous coal’s mass fraction up to 50%the compressive strength of carbon membranes was twice stronger than it used to be,and the detonation strength exceeded 5MPa.Short carbon fibre can improve the impact strength and rich the pore structure of coal-based carbon membranes.The impact strength of carbon membranes was enhanced from 1.03 KJ/m2 to 4.14 KJ/m2 after the carbon fibre was mixed in.Bituminous coal can improve the composite between short carbon fiber and coal-based carbon membranes.In this work,two different coal-based tubular carbon membranes（bituminous coal carbon membrane and mixed coal carbon membrane）have been served as the supports of C/C composite membranes for gas separation.The supports were then coated with Polyethersulfoneketone（PPESK）by dip-coating and pyrolyzed to prepare the C/C composite membranes.The results show that the pore structure of the supports have marked effect on the separation characteristic of the composite membranes.The selectivities of mixed coal support C/C composite membrane with H2/N2,O2/N2,CO2/N2 were 23.68,3.93,8.97 respectively after dip-coating four times.The selectivities of bituminous coal support C/C composite membrane with H2/N2,O2/N2,CO2/N2 were 104.70,13.66,21.80 respectively after dip-coating twice.
Tetrapod-like zinc oxide whisker （T-ZnOw） is one kind of multifunctional inorganic material with uniform three-dimensional structure. High pure zinc powders are unreasonably demanded in the present production techniques and fussy processing of zinc powder is a prerequisite in some cases. So the mass production is difficult to achieve and higher costs hinder its further application in many fields. From these considerations, this study explored the optimum process conditions of preparing T-ZnOw by direct oxidation of non high-grade Zn powders at ambient pressure on the basis of in-depth study of the theory of nucleation and growth. The effects of aluminum doping on the electrical resistivity of T-ZnOw were investigated. T-ZnOw doped with gallium was prepared and it had good electric conductivity preformance.In this thesis, many factors having the impact on whiskers size, shape and yield were studied systematically in synthesizing T-ZnOw and the optimum process conditions were explored. The structure and morphology of ZnO whiskers were characterized by Scanning Electron Microscopy （SEM） and X-ray diffraction（XRD）. The results show that these whiskers are single crystal with hexagonal wurtzite structure, length of whiskers range from 30μm to 65μm, the average length is 50μm, diameter of whiskers range from 2μm to 5μm, and the average diameter is 3μm. The growth of ZnO whiskers is determined mainly by two factors: one is the supersaturation of ZnO above the substrates, and the other is the crystallization property of ZnO material itself. The supersaturation of ZnO is the most impotant and can be regulated by controlling the temperature and reaction rate. The experimental results showed that when pre-heating rate is 5°C/min, the morphology of T-ZnOw is the most perfect and the yield is as high as 95 percent. With the improvement of pre-heating rate, the product is uneven tetrapods zinc oxide whiskers, and whisker size increases. With the reaction temperature increasing, whisker size reduced, but the yields and integrity of whisker have decreased.In this paper, intrinsic defects doping of the Tetra-ZnO whiskers were used to make a breakthrough in conducting electricity function. The micro-morphology, crystal structure, conducting properties of doped T-ZnOw were measured and analyzed. T-ZnOw were doped with Al、Ga by solution absorption blending pretreatment following by high temperature diffusing process. The result showed that T-ZnOw lost parts of needle point and some grains covered the whiskers surface. The formation of ZnGa2O4 and ZnAl2O4 can be observed by carefully examining the XRD patterns of doped T-ZnOw especially when dealing with highly doped samples. The electric conducting properties of the doped samples were characterized by electric resistance tests. Both Al and Ga doped T-ZnOw have an increase in conductivity. The electrical resistivity of T-ZnOw doped with Al reduces by four orders of magnitude, and for T-ZnOw doped with Ga, it decresed by seven orders of magnitude.
Carbon foams, which exhibit an interconnected structure and a large porosity made up of macrospores, are important in many areas of modern science and technology, including aerospace, heat exchanger, catalyst support and electrode material due to their remarkable properties, such as low density, high open-cell ratio, low coefficient of thermal expansion, resistance to corrosion, easy machining and other superior performances. Moreover, Composites with specific properties can be obtained via combination of carbon foam with other materials.In the present thesis, carbon foams were prepared using polyurethane foam as template and furfuryl alcohol （FA）, polyimide acid （PAA） as well as asphaltene （AS） extracted from CLR as carbon precursors. The synthesis process involves the impregnation of the carbon resources, solidification and carbonization. The products were characterized by scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The basic parameters, electric conductivity and antioxidant ability were also investigated. The results indicate that the as-prepared products which have low density and high porosity are made up of interconnected ligament composed by turbostraic carbon structure.The products are semiconducting materials and show good antioxidant ability. The structure and impregnation ability of the template is improved via the pretreatment by alkali solution, consequently the carbon foam with higher open porosity; carbonization yield as well as bulk density can be obtained. In order to expand the application of carbon foams, composites were also synthesized by adding Ni （NO3）2 and CNT into polyamide acid. This thesis not only enriches the category of materials for the preparation of carbon foams, but also makes valuable contributions to the research and application of carbon foams.
The optics, electric, thermodynamics and magnetism properties of magnesium hydroxide nanorods are very different from the common magnesium hydroxide. The magnesium hydroxide nanorods is widely used in flame-retardant area, nano-magnesium oxide ceramic, neutralizer in environment protecting field, desulfurizer in flue gas and so on. Common magnesium hydroxide as flame-retardant will be effective when the loading is as high as 40 percent., which will largely decrease the mechanical property. The product of magnesium hydroxide nanorods will help to solve the problems. The liquid method concerning the preparation method of magnesium hydroxide nanorods is the most common method and there are some other methods such as liquid-solid arc discharge technique and Pulsed-laser ablation of Mg in liquids.The magnesium hydroxide nanorods were prepared by precipitation conversion method, using basic magnesium chloride as precursor and sodium hydroxide as precipitation conversion agent. The effects of these reaction factors, such as the solvent, mol ratio of reactants and concentration of sodium hydroxide etc, to the morphology of magnesium hydroxide nanorods, were studied. The products are characterized and detected by the following means, such as the X-ray diffraction, Scanning Electron Microscopy （SEM） and so on. The results indicate that the solvent and the morphology of basic magnesium chloride are the main effecting factors. The best condition of the preparation of reactants is as followed: the solvent is ethanol; the mol ratio of sodium hydroxide to basic magnesium chloride rods is 2:1; the concentration of sodium hydroxide is 2mol/L; reaction temperature is 60℃; reaction time is 1 hour. Well-crystallized single-crystal magnesium hydroxide nanorods with diameter of 100-200nm and length of 6μm were obtained.Magnesium chloride hexahydrate （MgCl2·6H2O） , urea（H2NCONH2） , magnesium oxide（Light） and ammonia were the reactants, and different morphological magnesium hydroxide materials were prepared by liquid phase method. The drying curves and drying rate curves were obtained by drying kinetics experiments. The equilibrium moisture adsorption isotherms of magnesium hydroxide of three morphological micro-nanostructures at room temperature were gained. The results indicate that drying rate curves of magnesium hydroxide microparticles exhibit three stages: a set-up period, a constant rate drying period and a falling rate drying period. And drying rate curves of magnesium hydroxide nanosheets（ nanosheets1 and nanosheets2） show the similar three stages with a little descending trend in constant rate drying period. It is also found that the initial moisture contents, critical moisture contents and equilibrium moisture contents of Mg（OH）2 nanosheets are larger than those of Mg（OH）2 microparticles under the same drying conditions. The drying math models of nanosheets and microparticles are obtained. It is found that the results of simulation by drying math models are in good agreement with experimental data, and therefore drying math models found could adequately describe the drying behavior of the according micro-nano magnesium hydroxide products.The experiment of surface modification of magnesium hydroxide nanorods with stearic acide was processed. The modification effects of the dosage of stearic acide and modification time to magnesium hydroxide nanorods were investigated. The products were characterized and detected through the X-ray diffraction and IR analysis. It is shown that the dosage of stearic acide is 5% and the modified time is about 1 hour.
The influences of fermentation conditions and substrate components on bacterial cellulose produced by Acetobacter xylinum is studied in this paper. The optimum technology is gotten. Watermelon juice is used as substrate to produce bacterial cellulose for the first time, the result is as good as we thought.The structure and properties of bacterial cellulose are studied by all kinds of equipments and methods. SEM indicates that the product has minuteness and net microstructure. Element analysis shows that the contents of C、H、O in the product are accordance with their contents in common cellulose. The infrared spectrum has the result that the groups in molecules of the product belong to cellulose. X-ray diffraction is used to test the crystal type of the product, and heat weightlessness analysis studies its thermal property. Water-holding property of bacterial cellulose and its adsorption to mental cations are tested in this paper, the results indicate that the product has excellent water-holding property and strong adsorption to Cu2+. Bacterial cellulose can be dissolved in LiCl/DMAC、NMMO·H2O and formic acid, but not in solvents of sodium hydroxide/urea sodium、hydroxide/thiourea and lithium hydroxide/urea.Bacterial cellulose dissolved in NMMO is treated on PET fabric, the hydrophile and antistatic properties of the fabric are improved greatly, which can endure washing in some extent. However, the physical and mechanical properties of the fabric are influenced too. That is, gas permeability and whiteness of the fabric decline, the breaking strength and tearing strength change little.Bacterial cellulose has many unique properties, the studies in this paper has built the foundation to develop its applycation on textile, and hopefully it can open new field for hydrophile treatment of PET fabric.
Recently, Synthesis of nano-/ micro- particles in soft templates has received considerable attention. Studies on the templates of surfactant and macromolecule are the most active research fields. People wish to control the size, morphology and structure of the materials basing on the limited space and controllable effect of the template composition.In this paper, the interaction between nickel ions and sodium dodecyl sulfate(SDS)- polyvinylpyrrolidone(PVP) cluster was investigated by means of surface tension and Zeta potential method. The results showed that the existence of nickel ions would not destroy the formation of cluster by PVP and SDS bound-micelle. Theγ-lgc curves of NiCl2-SDS-PVP systems still held two critical concentrations: the first critical concentration (c1) and the second critical concentration (c2). The increase of nickel ions’concentration favored the formation of bound-micelle, and making surface tension decreased further. In the meantime, c1 decreased while c2 increased with ever-increasing level of nickel ions. With the increasing concentration of PVP, the first critical concentration c1 was basically unchanged while the second critical concentration c2 increased correspondingly. Therefore, the clusterization boundary of SDS-PVP cluster extended, and the controllable range of soft template in preparing ultrafine nickel powders increased accordingly.Ultrafine nickel powders were prepared from nickel chloride reduced by hydrazine in aqueous solution of sodium dodecyl sulfate (SDS)-polyvinylpyrrolidone (PVP). SEM proof showed that the reduced products were sphere with special needle-like morphology which average diameters were about 400-800 nm. XRD displayed that the spherical ultrafine nickel powders were self-assembled into by the primary pure crystalline nanonickel of face centric structural (fcc) with the mean crystal size about 10 nm, and grown preferentially along (111) lattice plane. The process that the primary pure crystalline nanonickels self-assembled into the ultrafine nickel powders in virtue of the coupling of PVP chain was clearly observed by TEM. Thus we get the following conclusions: In the process of preparing ultrafine nickel powders, the primary pure crystalline nanonickels similar to the size of soft template developed in the first microreactor of SDS bound micelle, then closed with each other and assembled orderly in virtue of the coupling of PVP chain, self-assembled into ultrafine nickel powders at last. It showed that the SDS-PVP cluster with structure of two-ply soft template played a particular role of twice induced self-assemble function in the synthesis of ultrafine nickel powders. The composition of the SDS-PVP mixing system had great influence on the size and shape of ultrafine nickel powders .At a certain concentration, the size of the primary pure crystalline nanonickel and the secondary ultrafine nickel powders showed a decreased trend with the higher concentration of SDS or PVP. It was revealed a promising possibility of a size and morphology controllable production of the ultrafine nickel particles by adjusting the composition of SDS and PVP. UV-Vis spectra were employed to monitor the reaction process and investigate the optical properties of the system. It was found that the absorption peak in the UV-Vis spectras of nickel sols was blue-shifted with the decreasing of ultrafine nickel powders’average diameter by studying the effect of SDS, PVP and NiCl2′ concentration.