Pd-M(Ag,Cu) bimetallic catalysts can be easily prepared via in situ reduction of the corresponding Pd2+,Ag+ and Cu2+ that the coordination interaction took place between the metal ions and amide of poly(N,N-diethylacrylamide)(PDEAm) using as-prepared PDEAm grafted poly(acrylonitrile/styrene)(PDEAm-g-PAN/PSt) microspheres as carrier.The ultrafine dispersed Pd-M(Ag,Cu) bimetallic nanoparticles were loaded on the surfaces of the PDEAm-g-PAN/PSt microspheres.The Pd-M bimetallic catalysts were characterized by transmission electron microscopy(TEM),X-ray diffraction(XRD),energy dispersive X-ray spectrum(EDS) and thermo-gravimetric analysis(TGA).The results show that PDEAm-g-PAN/PSt microspheres have obvious flower-shape morphology,and Pd-M(Ag,Cu) nanoparticles are formed on the surface of polymer microspheres with the average particle size in about 10nm,and the catalytic efficiency of the Pd-M(Ag,Cu) is evaluated in hydrogenation reactions of 1-octylene.The catalytic efficiency of Pd-M bimetallic catalysts is higher than that of Pd/C,and the efficiency order is Pd-CuPd-AgPd/C.
A series of thermochromic composite materials composed of bromocresol green(BCG) and rare earth metal ions were prepared.The effects on thermochromism by the sort and ratio of delomorphic reagent and solvent were studied.Based on the identification of FT-IR,UV-Vis and DSC analysis,the thermochromic mechanism of composites were summarized for electron gain or loss among the molecules.At room temperature,quinonoid BCG is coordinated with rare earth metal ions.After warming,the complex was separated,lactone ring structure is recurring on BCG.Therewith,the color inversion can be realized with temperature variation.
Poly(methyl methacrylate) grafted poly(ethylene glycol) (PMMA-g-PEG) copolymers were prepared by radical copolymerization of methyl methacrylate (MMA) and poly(ethylene glycol) macromonomer (MA-PEG) with a methacryloyl end group in N,N-dimethylformamide (DMF) using 2,2'-azobisisobutyronitrile as free radical initiator. Molecular weight distribution of the resulting PMMA-g-PEG copolymers was 1.7 based on the analysis of GPC. The structures of the PMMA-g-PEG copolymers were characterized by proton nuclear magnetic resonance (1H-NMR). The results of NMR show that structure of the PMMA-g-PEG copolymer is clear. Critical micelle concentration (CMC) of the PMMA-g-PEG and the solubilization of pyrene from H2O/DMF mixed solvents to the micelles of PMMA-g-PEG copolymer were determined using pyrene as fluorescence probe. The results show that the PMMA-g-PEG has a low CMC and solubilization of pyerne depends upon water content in the mixed solvents. The shape of micelle with about 180 nm in diameter was observed by transmission electron microscopy (TEM). The micelle had a stabilization form through self-assembly of PMMA-g-PEG copolymer.
Sodium 1,4-butanediol bisulfosuccinate diester was synthesized from 1,4-butanediod, maleic anhydride and 1-octadecanol. The diesterfication reaction was catalyzed with phosphotungstic acid supported on silica (PW12/SiO2). The optimized conditions for the esterification were determined with orthogonal experiments as:molar ratio of 1,4-butanediol bismaleic acid monoester to 1-octadecanol was 1.00 : 2.20, amount of catalyst was ω=1.5%, reaction temperature was 150℃,reaction time was 8h,the esterification rate could reach to 97.2 % and the yield was up to 84.9%. The sulfonation reaction was carried out with the molar ratio of 1,4-butanediol bismaleic acid diester to NaHSO3 of 1.00 : 3.00 and 1.5% catalyst (cetyltrimethylammonium bromide) at 90℃ for 4h,the sulphonation rate could reach to 92.7 % and the yield was up to 74.9%. The obtained sodium 1,4-butanediol bisulfosuccinate diester has a surface tension γcmc of 41.9mN/m,a CMC of 7.2×10-5 mol/L in aqueous solution at 25 ℃,indicating that the surfactant has a low CMC.
Fe3O4 nanoparticles were synthesized by chemical co-precipitation.Then adding a mount of sodium oleate to modify the surfaces of the nanoparticals to obtain the oil-base Fe3O4 nanoparticles which average diameter was 12.7nm.The core-shell structured magnetic composite microspheres with poly(acrylic acid)-co-poly(methyl methacrylate)(PAA-PMMA) as shell and Fe3O4 as core were prepared by dispersion polymerization using divinylbenzene(DVB) as cross-linking agent,2,2'-azobisisobutyronitrile(AIBN) as initiator,poly(vinylpyrrolidone)(PVP) as stabilizer in the presence of oil-base Fe3O4 nanoparticles.The effect of the ratio of ethanol to water,amount of AIBN,PVP and DVB on the microsphere formation were investigated.The optimum recipe was finally obtained.The structures,morphologies,diameter,diameter distribution and magnetic amount of the magnetic composite microspheres were characterized.
P(St-co-MMA) microspheres were prepared by photoinitiated emulsion polymerization of styrene(St) with methyl methacrylate(MMA) in water using 2,2-dimethoxy-2-phenylacetophenone(BDK) and sodium dodecyl sulfate(SDS) as the initiator and emulsifier,respectively.The effects of initiator,amount of SDS on the yield and diameter of P(St-co-MMA) microspheres were studied,then compared with photoinitiated dispersion polymerization.The results showed that the rate of photoinitiated emulsion polymerization was faster than that photoinitiated dispersion polymerization,and the diameter of P(St-co-MMA) microspheres can be controlled in range from 70 to 140 nm.
The surface modification with silicon coupling reagent to ultrafine silicon dioxide,which roots in waste production in fiber manufacturing,was investigated in this paper.The experimental results show that the surface Si-OH bonds infrared intensity of ultrafine silicon dioxide was decreased and thermogravimetric loss was increased by using Fourier infrared(FTIR) spectroscopy and thermogravimetric(TG) analyzer.The result also indicates the surface Si-OH bonds of ultrafine silicon dioxide has reacted with silicon coupling reagent.By using laser light scattering(LLS) and scanning electron microscopy(SEM),the particle sizes of ultrafine silicon dioxide diminish and the congeries dispersibility were obviously improved,which shows that the hydrophobic property of ultrafine silicon dioxide after being modified has been much more strengthened,This surface modification provides wide market to reuse ultrafine silicon dioxide waste material.
The block copolymer of ethylene oxide was prepared using propylene oxide(EO20PO70EO20,P123) as template and Titanium(IV) isopropoxide(TTIP) as the inorganic precursor in the study.The transparent gel of TiO2 was prepared by Sol-gel method at 60℃ and mesoporous TiO2 was obtained through calcination.The structure,morphology,crystalline size,specific surface area,pore size and photocatalytic activity of resulting samples were characterized by using X-ray diffraction,high-resolution transmition electron microscopy(HRTEM),N2 adsorption-desorption and UV-vis spectrometer(UV-vis) techniques.The results show that obtained sample heat-treated at 400℃ arrays ordered mesoporous partly,owns high Brunauer-Emmett-Teller(BET) surface area and high photocatalytic activity through changing ratio of TTIP to P123 and ethanol.
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