Atomic force microscope studies of membranes: Surface pore structures of Cyclopore and Anopore membranes

Non-contact atomic force microscopy has been used to investigate the surface pore structure of Cyclopore and Anopore microfiltration membranes in air. Three Cyclopore membranes and three Anopore membranes of different pore sizes were studied. Excellent high resolution images were obtained. Analysis of the images gave quantitative information on the surface pore structure, in particular the pore size distribution. Non-contact AFM is an excellent means of obtaining such information for microfiltration membranes.     

天然高分子表面活性剂

综述了淀粉、纤维素和壳聚糖类表面活性剂的合成方法、性质及功能。     

聚合物假冠醚研究 (II)新型聚合物的合成、吸附特性与绿色应用

合成了两种假冠醚型聚合物。研究了聚合物对金属离子的静态吸附性能。结果表明,聚合物对Ag+,Pb2+,Hg2+ 表现出良好的吸附特性,且聚合物B的吸附能力优于聚合物A。吸附实验表明,除冠醚氧原子参与配位外,-CH2OH的氧原子亦参与了配位。聚合物B对Ag+的吸附过程中存在着明显的氧化还原现象,Ag+ 被还原为Ago,而聚合物分子中的 -CH2OH被氧化成为 -COOH。已初步将研究成果应用于本化学实验室的绿色化建设中。     

Ion exchange behaviour of polymeric zirconium cations

Summary Polymeric zirconium cations formed in weakly acid solution (pH2) are taken up strongly into macroporous cation exchange resins, while uptake into normal cation exchange resins (pore diameter about 1 nm) is low. Macroporous cation exchange resins loaded with polymeric Zr cations are shown to function as ligand exchange sorbents.

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Ionenaustauschverhalten polymerer Zirkonium-Kationen (Kurze Mitt.)

Zusammenfassung Polymere Zirkonium-Kationen, die in schwach sauren Lösungen (pH2) vorliegen, werden von makroporösen Kationenaustauschern stark aufgenommen, während bei den üblichen Kationenaustauschern (mit Porengrößen von etwa 1 nm) nur geringe Aufnahme stattfindet. Makroporöse Kationenaustauscher die mit polymeren Zr-Kationen beladen sind fungieren als Liganden-Austauschsorbentien.

     

HPLC determination of morphine with amperometric detection at low potentials under basic pH conditions

Summary A simple, sensitive, accurate and reliable method for morphine determination in biological samples has been developed. It uses reverse-phase HPLC on a polymeric column with an eluent (0.05 mol/L dibasic sodium phosphate: acetonitrile, 8515) at pH 9.5, allowing both the suppression of ionization of morphine amine and the promotion of oxidation of the phenolic group. Amperometric detection at mild oxidizing potential (350 mV) proves very selective, and, therefore, only a simple and rapid one-step liquid-liquid sample preparation is required. Under these conditions clean chromatograms are obtained even with complex biological matrices such as cadaveric blood, urine and hair.Minimum detectable amount of morphine is about 200 pg injected. A calibration line with a correlation coefficient of 0.99996 has been produced over the range 7.5–250 ng/mL. Precision results comparable to other HPLC methods.A preliminary report was presented at the 25th T.I.A.F.T. Meeting 1988, Groningen (NL), June 27–30 1988.     

Polymeric photoinitiators based on side-chain benzoin methyl ether and tertiary amine moieties for fast UV curable coatings

The synthesis is reported of a new series of polymeric photoinitiators obtained by copolymerization of a-methylolbenzoin methyl ether acrylate (MBA) with different N,N-dialkylamino alkyl acrylates. The copolymers have been fully characterized and employed in the photoinitiated polymerization and crosslinking reactions of a standard acrylic formulation for clear curable coatings. The photoinitiation activity of the above systems has been measured by using microwave dielectrometry and differential photocalorimetry, and compared with that found for the corresponding low-molecular-weight models. The results clearly indicate that the copolymeric systems display a remarkable decrease of the induction period and an improved overall activity in the UV curing of the acrylic coatings. An interpretation of the experimental findings is also reported.     

倒浮萍聚合物LB膜的有序－无序相变研究

倒浮萍聚合物ＬＢ膜的有序－无序相变研究李宏斌，张希，张瑞丰，赵冰，徐尉青，沈家骢，高忠民（吉林大学分子光谱与分子结构开放实验室、化学系，分析测试中心，长春，１３００２３）关键词聚合物ＬＢ膜，有序－无序相变，变温红外光谱，变温小角Ｘ光衍射ＬＢ膜的有序－...     

Polymeric membranes based on cellulose acetate loaded with candle soot nanoparticles for water desalination

This study is concerned with modifying cellulose acetate (CA)/polyethylene glycol (PEG) membranes prepared via phase inversion technique in the presence of carbon nanoparticles; candle soot (CS) resulting from combusted candle. CS nanoparticles were analyzed via Fourier transform infrared spectroscopy and transmission electron microscopy. The developed membranes were characterized for their surface morphology, mechanical properties as well as thermal stability. CS nanoparticles contributed in improving the salt rejection % with a slight reduction in the water flux behavior. Employing the annealed cellulose acetate/polyethylene glycol membranes loaded with candle soot nanoparticles provides an adequate approach towards water desalination implementations.     

Structural and optical properties of nanocrystalline ZnO thin films synthesized by the citrate precursor route

Nanocrystalline zinc oxide (ZnO) thin films have been deposited by spin-coating polymeric precursors synthesized by the citrate precursor route using ethylene glycol and citric acid as chelating agents. The ZnO thin films were annealed in air at different temperatures for 10 min. The films were characterized by different structural and optical techniques, including X-ray diffraction (XRD), atomic force microscopy (AFM), optical transmission spectroscopy, and photoluminescence (PL). The thermal decomposition of polymeric precursor was studied by thermogravimetric analysis (TGA). XRD analysis with grazing incidence and rocking curves indicate that the ZnO films are polycrystalline with preferential orientation along the c-axis direction with a full-width at half-maximum (FWHM) of 0.31° for 600 °C-annealed samples. On annealing, the texturing in films increased along with a decrease in FWHM. AFM micrographs illustrate that the ZnO films are crack-free with well-dispersed homogeneous and uniformly distributed spherical morphology. The synthesized ZnO thin films have transparency >85% in the visible region exhibiting band edge at 375 nm, which becomes sharper with anneal. Room temperature PL spectra of these films show strong ultraviolet (UV) emission around 392 nm with an increase in intensity with annealing temperature, attributed to grain growth. Deconvolution of the PL spectra reveals that there is coupling of free excitons with higher orders of longitudinal optical (LO) phonon replicas leading to a broad asymmetric near-band-edge peak.