LB膜模板诱导晶体取向生长

LB膜作为模板可诱导晶体取向成核和外延生长，生成的晶体材料具有独特的微观结构和优异的物理化学性能。这种方法对于生物矿化现象的研究以及新颖材料合成策略的设计等方面具有重要的启示意义。本文从LB膜诱导晶体取向生长的机理及利用等方面综述了该领域研究的最新进展。

Ring-opening polymerization of epsilon-caprolactone by lanthanocene catalysis

Ring-opening polymerization of epsilon-caprolactone (CL) catalyzed by lanthanocenes, O(C2H4C5H3CH3)(2)YCl (Cat-YCl) and Me2Si[(CH3)(3)SiC5R3](2)NdCl (Cat-NdCl) has been carried out for the first time. It has been found that both yttrocene and neodymocene are very efficient to catalyze the polymerization of CL, giving high molecular weight poly(epsilon-caprolactone) (PCL). The effects of [cat]/[epsilon-CL] molar ratio, polymerization temperature and time, as well as solvents were investigated and polymerization temperature is found to be the most important factor affecting the polymerization. The bulk polymerization gives higher molecular weight PCL and higher conversion than that in solution polymerization. NaBPh4 was found to promote the polymerization of epsilon-caprolactone, and thus to increase both the polymerization conversion and MW of poly(epsilon-caprolactone).

Macrocyclic oligomeric arylene ether ketones: Synthesis and polymerization

Some novel macrocylic(arylene ether ketone)oligomers were synthesized in high yields by a nucleophilic aromatic substitution reaction of 4,4'-dinitrobenzophenone with bisphenols in the presence of anhydrous potassium carbonate under pseudo-high-dilution conditions. Detailed structural characterization of these oligomers by matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS), H-1 NMR and FT-IR confirmed their cyclic nature and the compositions of the oligomeric mixtures was indicated by GPC analysis. Ring-opening polymerization of cyclic oligomers 3a to a high molecular weight polymer with M-w of 52.3 and M-n of 17.2 k was achieved by heating at 280 degrees C for 40 min in the presence of a nucleophilic initiator.

草酸沉淀法合成LiCoO_2正极材料

用草酸沉淀法合成了LiCoO2，用TG、IR、XRD对合成条件和产物结构进行了研究，结果表明最佳的合成条件是：草酸／CoAc2＝1：1、pH＞6、850℃、8h焙烧，首次充电容量可达140mAh／g以上。

Red color filter in an organo-soluble polyamide matrix for liquid crystal displays

A red color filter was laminated from a solution of red color pigment and an organo-soluble polyamide, based on 1,4-bis(3,4-dicarboxyphenoxy) benzene dianhydride (HQDPA) and 2,2'-dimethyl-4,4'-methylene dianiline (DMMDA). The red color filter in a polyamide matrix with negative birefringence plays an important role in twisted nematic liquid crystal displays (TN-LCDs). The red color filter, and also compensation films, extend the viewing angle of LCDs. (C) 1997 Elsevier Science S.A.

Direct deposition and characterization of Langmuir-Blodgett monolayers of soluble polyimides

Langmuir-Blodgett (LB) monolayers of three kinds of soluble polyimides were prepared with the direct deposition method, The monolayer structures were characterized with W-vis absorption spectroscopy, the wide angle X-ray scattering method and electrochemical techniques. The polyimide molecules in the LB monolayers lie orderly on the substrate surfaces with the orientation in which the dianhydride group is normal to the substrate surface and two carbonyl oxygen groups close to the surface. Therefore, the thickness of the three kinds of polyimide LB monolayers are the same because it depends on the distance between the two carbonyl oxygen groups in the same ring. The area of monomeric units are dependent on the length of the diamine group. The model of the molecular packing proposed from the quantomechanical calculation is in good agreement with the experimental results. (C) 1997 Elsevier Science S.A.

The synthesis and thermotropic liquid crystalline behavior of the novel poly(aryl ether ketone)s containing chloro-side group

The novel poly(aryl ether ketone)s containing chloro-side group were synthesized by nucleophilic substitution reactions of 4,4'-biphenol and chlorohydroquinone with either 4,4'-difluorobenzophenone(BP/CH/DF) or 1,4-bis(p-fluorobenzoyl)benzene (BP/CH/BF) and their thermotropic liquid crystalline properties were characterized by a variety of experimental techniques. The thermotropic liquid crystalline behavior was observed in the copolymers containing 50 and 70% biphenol. Melting transition (Tm) and isotropization transition (Ti) both appeared in the DSC thermograms. A banded texture was formed after shearing the sample in the liquid crystalline state. The novel poly(aryl ether ketone)s had relatively higher glass transition temperature (Tg) in the range of 168 similar to 200 degrees C and lower melting temperature (Tm) in the range of 290 similar to 340 degrees C. The thermal stability (Td) was in the range of 430 similar to 490 degrees C.

A study of the radical reaction of C-60 with n-Bu(3)SnH

The reaction of buckministerfullerene (C-60) with tri-n-blltyltin hydride(n-Bu(3)SnH) in toluene solution has been investigated. According to mass spectrometry analysis, the products of above reaction are C-60(BuH)(n)(n = 1 similar to 3) and Bu(x)Sn(y)H(x) (x = 3 similar to 8, y = 1 similar to 4,approximate to = 0 similar to 3). The reaction maybe provide a new method for the synthesis of alkylated fullerene derivatives. Where C-60 also takes a role of a catalysis of organtic-tin polymerization. The radical reaction mechanism has been discussed.

C_（60）与n－Bu_3SnH的自由基反应研究

Ｃ_（６０）与ｎ－Ｂｕ_３ＳｎＨ的自由基反应研究余益民，郭兴华，刘子阳，刘淑莹，傅芳信，钱明星（中国科学院长春应用化学研究所，长春，１３００２２）（东北师范大学化学系）关键词自由基反应，富勒烯，三丁基锡氢化物，自由基海绵自Ｋｒａｔｓｃｈｍｅｒ等［１］实...

EFFECTS OF STRUCTURE MULTIPLICITY ON MECHANISM OF RADIATION CROSS-LINKING OF POLYMERS

In an attempt to explore the effects of structural multiplicity of polymers on the mechanism of radiation crosslinking, the adaptability of the Charlesby-Pinner's equation and its various modified versions are examined. It is recognized that both chemical

A Study of the Heterogenization of Heteropoly Acid (II)

The surface chemical species of surface-modified activated carbons and adsorption of 12-silicotungstic acid (SiW12) on them were studied It was found that these carbons have different adsorption isotherms and adsorptive force. The carbonyl groups on the s

杂多酸的固载化研究(Ⅱ)

研究了以多种方法化学改性的不同活性炭表面化学特性及十二硅钨酸（SiW12）在相应表面的吸附.首次提出，不同原料来源和改性的活性炭对SiW12的吸附有不同的等温线形式和吸附力.活性炭表面的羰基有利于SiW12的吸附，而表面的羧基则是不利的.

HOST-GUEST INTERACTIONS OF THIAMINE WITH ANIONS - CRYSTAL-STRUCTURE OF THIAMINE IODIDE SESQUIHYDRATE

The crystal structure of thiamine iodide sesquihydrate has been determined by X-ray diffraction methods as a host-guest model for coenzyme-substrate interactions. The asymmetric unit contains two chemical units. Both the thiamine molecules A and B, which are crystallographically independent, assume the usual F conformation and have a disordered hydroxyethyl side chain. An iodide anion (or a water molecule) bridges the pyrimidine and thiazolium rings of molecule A (or B) by forming a hydrogen bond with the amino group and an electrostatic contact with the thiazolium ring to stabilize the molecular conformation. In the crystal the thiamine molecules self-associate to form a pipe-like polymeric structure, in which four thiamine hosts surround an iodide guest and hold it through C(2)-H...I hydrogen bonds and thiazolium...I electrostatic interactions. Crystal data: C12H17N4OS+.I- . 1.5 H2O, monoclinic, P2(1)/c, a = 12.585(2), b = 25.303(5), c = 12.030(2) angstrom, beta = 115.15(1)degrees, V = 3468(1) angtrom3, Z = 8, D(c) = 1.606 g cm-3, R = 0.045 for 3328 observed reflections.

介体型双酶D-氨基酸传感器的制备

用一种全氟代磺酸酯阳离子交换树酯(East-man AQ-55),将D-氨基酸氧化酶(DAAO),辣根过氧化物酶(HRP)以及1,1′-二(α-羟基乙基)二茂铁(BHFc)同时包埋在玻碳电极(GCE)表面,制成双酶D-氨基酸电流式传感器。电极的工作电位为+0.18V(vs.SCE)响应时间小于50s。对于D-丙氨酸来说,测定的最适宜pH为7.8,测定的线性范围为0.05～0.75mmol/L该电极具有良好的重现性,可以连续使用200次。

辐射法一步合成淀粉—丙烯酸(盐)高吸水树脂

高吸水树脂是一种用途广泛的功能高分子材料,自70年代末问世以来,在国际上发展极为迅速。国内从80年代初开始研究,发展也很快。其中以淀粉为原料制备高吸水树脂,在国内倍受重视,并已有文献报导。大部分工作是用化学接枝的方法,用引发剂如硝酸铈铵,Fe~(++)—H_2O_2,KMnO_4等,使淀粉与丙烯睛,或丙烯酰胺、丙烯酸(盐)进行接枝聚合,然后皂化水解而得高吸水树酯,对于辐射接枝聚合,制备淀粉—丙烯酸系高吸水树脂,则报导很少。从已有的工作看到,无论采用化学接枝还是采用辐射接枝,所得产物都需经过皂化水解,方能获得高吸水性树脂。