毛细管电泳法分离联萘酚对映体

利用新的手性选择剂苄基氯化辛可宁，在非水相中成功地分离了联萘酚的对映体，并对分离的机理作了初步地探讨。     

Asymmetric molecular sieve carbon membranes

An asymmetric molecular sieve carbon membrane is obtained by conventional pyrolysis of a thermosetting polymeric film, followed by unequal oxidation. Morphology, pore size distribution, and gas separation characteristics of the membrane are discussed. The transport mechanism for gas permeation is clearly non-Knudsen diffusion since heavier oxygen permeates faster than lighter nitrogen. The proposed mass transfer mechanism is that of a molecular sieve.     

在多孔γ-Al2O3氧化铝载体上微波合成NaA分子筛膜及气体渗透分离性能

The paper presented novel synthesis of NaA zeolite membrane with good performance using microwave heating. The method involved two steps, prior seeding 120 nm of LTA crystals on substrate and then employing a secondary hydrothermal synthesis. Effects of seeding times, synthesis time and synthesis times were investigated in this work. The quality evaluation of membranes respectively used single component gases (HE and N2) and H2/N2 (equivalent volume) mixture. The ideal H2,/N2 selectivity increased from 1.90 of the substrate to 6.37 of the three-stage synthesized membrane, which was distinctly higher than the corresponding Knudsen diffusion selectivity of 3.74. However, the real H2/N2 selectivity of the three-stage synthesis was much lower than the corresponding ideal selectivity and close to the corresponding Knudsen diffusion selectivity of 3.74.     

Cadmium recovery by a sulfate-reducing magnetotactic bacterium,Desulfovibrio magneticus RS-1, using magnetic separation

Cadmium recovery by a sulfate-reducing magnetotactic bacterium, Desulfovibrio magneticus strain RS-1, was investigated. D. magneticus precipitated >95% of cadmium at an initial concentration of 1.3 ppm in the growth medium. Electron microscopic analysis revealed that D. magneticus formed electron-dense particles on its surface when cultivated in the presence of cadmium ions (Cd²⁺). Sulfide was also found in the precipitate, and the composition ratio of sulfide/cadmium was 0.7. Sixty percent of viable RS-1 cells was recovered by a simple magnetic separation revealing the removal of 58% cadmium from the culture medium.     

Poly(ether ketone)–polyisobutylene block copolymers: Synthesis and phase behavior

Telechelic poly(ether ketone)s (PEKs) and polyisobutylenes (PIBs) were combined to form PIB? PEK? PIB triblock copolymers and (PIB? PEK)_n multiblock copolymers via the formation of urea linkages. Monovalent and bivalent amino telechelic PIBs were prepared quantitatively from allyl telechelic PIBs by a newly developed reaction sequence featuring nucleophilic reaction steps. Telechelic PEK? NCO polymers were prepared from the corresponding amino telechelic PEKs via a reaction with diphosgene. The highly reactive PEK? NCO and PIB? NH₂ telechelics formed PEK? PIB block copolymers only quantitatively when appropriately reactive primary amino groups were present on the amino telechelic PIBs. The obtained block copolymers were microphase‐separated and featured mostly lamellar structures, as determined by small‐angle X‐ray scattering (SAXS). Temperature‐dependent SAXS measurements revealed ordered polymers in the melt up to 210 °C. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 188–202, 2005     

电荷转移器件检测器及其在分析化学中的应用

本文介绍了电荷转移器件检测的原理、类型和特征，评述了它们在分子光谱、原子光谱、拉曼光谱、分离科学、图象分析等分析化学领域中的应用研究概况，引用文献７４篇。     

Influence of the seed polymer on the chromatographic properties of size monodisperse polymeric separation media prepared by a multi-step swelling and polymerization method

Monodisperse polymer particle-based separation media were prepared by a multi-step swelling and polymerization method with two pairs of monomers and two porogenic solvents. Their chromatographic properties were compared to those of beads prepared by a corresponding suspension polymerization method without the use of seed polymer to ascertain the influence of the seed polymer on their porous structures. A large change in porous structure was observed when the swollen particle consisting of monomers and porogenic solvents contained at least one good solvent for the polystyrene seed polymer, allowing it to remain in the polymerizing medium. In contrast, when the polystyrene seed particle was excluded from the swollen oil droplets, due to its poor solubility in the monomers and the porogenic solvents, there was no difference in the chromatographic properties such as pore volume, pore size, pore size distribution, or retention selectivity between the multi-step swelling and polymerization method and the suspension polymerization method. Since the only difference between the multi-step swelling and polymerization method and the suspension method is the use of the seed polymer, it appears that a very small amount (< 1% v/v) of seed polymers in the enlarged swollen droplets plays an important role as a porogen and affects the porous structure as well as the chromatographic properties of the monodisperse polymer particle-based separation media. © 1993 John Wiley & Sons, Inc.     

Rodlike/flexible polyimide composite films prepared from soluble poly(amic diethyl ester) precursors: Miscibility,structure, and properties

Homogeneous precursor/precursor solutions with various compositions were obtained with appreciably high solid contents in N-methyl-2-pyrrolidone from soluble poly(amic diethyl ester) precursors of rodlike poly(p-phenylene biphenyltetracarboximide) (BPDA-PDA) and flexible poly(4,4′-oxydiphenylene biphenyltetracarboximide) (BPDA-ODA), which are hydrolytically more stable as well as more soluble than the corresponding poly(amic acid)s being equilibrated with the constituent monomers. Both optical microscopic and light scattering measurements showed that the dried precursor blend films and resultant polyimide composite films were optically transparent, regardless of compositions and process conditions. The composite films showed a single T_g behavior. However, for the composite of 30 wt % BPDA-PDA dispersed in the matrix of 70 wt % BPDA-ODA, a smectic crystalline-like aggregation of the BPDA-PDA component was detected on wide-angle x-ray diffraction patterns, indicative of microscopic phase separation between the two components. This phase separation was not detected on the optical microscopy, light scattering, and dynamic mechanical thermal analysis because of their resolution limits: Optical microscopy has a resolution of submicrometers, whereas dynamic mechanical thermal analysis and light scattering have a resolution of ca. 50 Å. Therefore, it is speculated that in the composite films BPDA-PDA and BPDA-ODA polyimide molecules have demixed on the scale of a few nanometers. The mean long periodicity, which was estimated from the small-angle x-ray scattering pattern, varied from 134 to 170 Å as the content of BPDA-ODA component increased. In addition, mechanical properties of the composite films were characterized. ©1995 John Wiley & Sons, Inc.     

Hyperbranched polyurethane as novel solid-solid phase change material for thermal energy storage

A series of novel hyperbranched polyurethane copolymer (HB-PUPCM) using hyperbranched polyester as chain extender was prepared via a two-step process. The phase transition behaviors and morphology of the HB-PUPCM films were investigated using differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMA), thermo-gravimetric analysis (TGA), wide-angle X-ray diffraction (WAXD), polarizing optical microscopy (POM) and tapping-mode atomic force microscopy (AFM). HB-PUPCM was proven to a good polymeric solid-solid phase change heat storage material.