The Modification of Calcium Lignosulfonate and Its Applications in Cementitious Materials

An azo calcium lignosulfonate (ACL) is synthesized by the coupling of a diazonium salt made from p‐aminobenzene sulphonic acid and calcium lignosulfonate (CL). The surface activity and foaming ability of ACL are evaluated; also the performances of ACL modified mortars such as fluidity and mechanical strength are investigated. Test results show that ACL has higher surface tension and lower foaming ability compared with CL, the disperse ability of ACL is stronger than that of CL at higher dosage than 0.5%, the flexural and compressive strength of ACL modified mortars are superior to that of CL modified mortars.     

羧基化氧化石墨烯的可控合成及血液相容性

采用自由基引发剂偶氮二异丁腈(AIBN)作为功能改性剂, 通过AIBN分解产生的异丁腈自由基进攻氧化石墨烯上五元环与七元环的缺陷点, 形成氰基改性氧化石墨烯中间体, 再通过水解反应制得羧基化氧化石墨烯[GeneO-C(CH₃)₂-COOH]纳米材料. 采用傅里叶变换红外光谱(FTIR), X射线衍射(XRD), 热重分析(TGA)和原子力显微镜(AFM)等方法对合成的材料进行了表征, 并采用复钙时间测试考察了材料的血液相容性. 研究结果表明, 氧化石墨烯中羧基的含量可以通过调整AIBN和GeneO的投料比来控制. 本方法不但可提高氧化石墨烯的羧基含量, 而且可使其具有良好的血液相容性.     

功能高分子磁性微球的制备及分析应用

通过分散聚合法制备功能高分子磁性微球 ,并有效地控制微球的粒径范围和微球表面活性基团。以乙醇 水为分散体系 ,对磁流体Fe3O4 表面进行苯乙烯和丙烯酸共聚反应 ,制得粒径均匀、分散性好、带有羧基的磁性微球。该微球经活化后和抗癌药物阿霉素结合 ,在自制磁性电解池中 ,可用金膜电极进行电化学检测。阿霉素磁性微球在 - 0 .4 0V处有一个明显的还原峰 ,在浓度为 7.2 5× 10 - 1 0 ～ 7.2 5× 10 - 9mol L范围内峰电流和阿霉素浓度的关系呈线性 ,检测下限达 3.6× 10 - 1 0 mol L。     

Synthesis and Evaluation of Anionic Copolymeric Surfactant as Dispersing Agent for Some Heterocyclic Azo-Dyes

Series of polymeric surfactants based on decylacrylate (M ₁ ) as hydrophobe and oxypropylated maleate (Mm _{2,4,6 and 8} with different molar ratios of propylene oxide) as hydrophiles were prepared by copolymerization in presence of 1mole% azobiisobutyronitrile (AIBN) as free radical initiator to afford [PMm₂, PMm₄, PMm₆, and PMm₈] _a–i . The reaction mixtures were followed by sulfation and neutralization to attain [PMmS₂, PMmS₄ PMmS₆, and PMmS₈]_a–i as anionic copolymeric surfactants, in good yield. These derivatives were purified and characterized by microanalysis, infrared, and ¹H-NMR spectra studies. Also, surface activity, dispersing properties, and biodegradability were evaluated. The prepared anionic copolymeric surface active agents revealed good surface activities and high dispersing properties above 70% special for PMms8_d with 8 mole propylene oxide and equal molar ratio from hydrophilic and hydrophobic monomers. Also, they are more biodegradable than traditional surfactants.     

Synthesis and Thermal Decomposition of Heavy Tetrylenes Bearing N-Aminocarbazolyl Substituents

The synthesis of the N-aminocarbazole R-NH₂ ( 2 ) is reported. Subsequent reaction with bis[bis(trimethylsilyl)amido]tetrylenes E[N(SiMe₃)₂]₂ (E=Ge, Sn, or Pb) allowed the isolation of formal hydrazidotetrylene derivatives, R−N(H)EN(SiMe₃)₂ ( 3 ) that includes the first example of a hydrazidoplumbylene to date. Thermal decomposition of these compounds resulted in the elimination of “NH” and afforded the tetrylenes R-EN(SiMe₃)₂ ( 4 ).     

Effect of Exogenous Carboxyl and Hydroxyl Groups on Pyrolysis Reaction of High Molecular Weight Poly(L-Lactide) under the Catalysis of Tin

The effect of exogenous hydroxyl, carboxyl groups and/or Sn~(2+) on pyrolysis reactions of poly(L-lactide)(PLLA) was investigated by thermogravimetric analysis(TGA). The activation energy(E_a) of pyrolysis reactions was estimated by the Kissinger-Akahira-Sunose method. The kinetic models were also explored by the Malek method, and the random degradation behavior was determined by comparing the plots of ln{-ln[1-(1-w)~(0.5)]} versus 1/T for experimental data from TGA with model reactions. The pyrolysis reaction rate of PLLA was affected slightly by exogenous hydroxyl and carboxyl groups at lower levels of Sn with 65-70 mg·kg~(-1) but increased appreciably in the presence of extraneous Sn~(2+), ―COOH/Sn~(2+), or ―OH/Sn~(2+). The E_a values for the pyrolysis reactions of the PLLAs that provided lactide were different under the catalysis of Sn~(2+) in different chemical environments because Sn~(2+) can form the new Sn-carboxylate and Sn-alkoxide with exogenous carboxyl and hydroxyl groups, which were different in steric hindrance for the formation of activated complex between Sn~(2+) and PLLA. Under the catalysis of Sn~(2+), a lactide molecule can be directly eliminated selectively at a random position of PLLA molecular chains, and the molecular chain of PLLA cannot change two PLLA fragments at the elimination site of lactide. However, it was regenerated into a new PLLA molecule with the molecular weight reduced by 144 g·mol~(-1).     

Steric effect and mobility of the alkyl chain in regio‐irregular poly‐3‐alkylthiophenes

The physicochemical properties of polyalkylthiophenes with various side‐chain length were widely investigated in order to reveal the functions of alkyl side‐chains in these polymers. The effects of the side‐chains on the properties of polyalkylthiophenes can be explained by their steric hindrance and mobility. The steric hindrance of alkyl chain affected not only the polymerization mechanism of the monomers but also the redox potential, interchain distance, charge transport properties, and film morphology. The mobility of the side‐chain influences the rate of dedoping, heat of transitions of polymers. The structure regio‐regularity, stability of polarons/bipolarons, film morphologies, and interchain interactions determine the optical and electric properties of polyalkylthiophenes. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 1763–1772, 1999     

富含羧基的球形介孔分子筛SBA-15的合成及药物释放性能

本文采用原位合成法合成了富含羧基的SBA-15球形介孔分子筛. 研究了修饰剂（三烷氧基氰乙基硅烷 CTES）的用量对介孔分子筛SBA-15形貌、孔径及BET比表面积的影响. 用粉末X射线衍射(XRD)、扫描电镜(SEM)、红外（IR）和氮气吸附/脱附对样品进行了详细的表征. 该材料展示了尺寸在0.5-1 μm规则的球形形貌、有序的二维六方相介孔结构、较大的比表面积和孔容、并且随着修饰剂用量的增加, SBA-15的孔径变小, 比表面积下降. 药物组装及缓释性能测试表明, 该材料具有较好的药物组装及缓释释放性能. 该材料在催化、药物载体和色谱分析填料等领域将具有潜在的应用.     

Direct Synthesis of Phenol from Benzene on an Activated Carbon Catalyst Treated with Nitric Acid

Commercially available coal-based activated carbon was treated by nitric acid with different concentrations and the resultant samples were used as catalysts for the direct hydroxylation of benzene to phenol in acetonitrile. Boehm titration, X-ray photoelectron spectroscopy, scanning electron microscope coupled with an energy dispersive X-ray microanalyzer, and Brunauer-Emmett-Teller method were used to characterize the samples. The number of carboxyl groups on the surface was found to be the main factor affecting the catalytic activity. An optimum catalytic performance with a yield of 15.7% and a selectivity of 87.2% to phenol was obtained.     

低组胺释放副作用的GnRH拮抗剂的设计合成及活性评价

根据肽类组胺释放剂具有多个碱性氨基酸的结构特点, 将具有羧基结构的基团引入促性腺激素释放激素(GnRH)的不同位置, 合成了一系列新的GnRH类似物, 并进行了大鼠体内抑制睾酮释放的生物活性评价及大鼠腹腔肥大细胞中的促组胺释放副作用评价. 结果表明, 某些带有酸性基团的GnRH类似物不仅组胺释放副作用大大降低, 而且保留了原有的生物活性. 该结果为研发具有低组胺释放副作用的安全型GnRH拮抗剂药物提供了新的构效关系信息.     

五苯基环戊二烯基氯化镥的合成

本文介绍高空间位阻的五苯基环戊二烯基氯化镥(包括单取代和双取代)的合成及鉴定。这二化合物要比文献上迄今所报道的其它稀土有机化合物有更高的空气稳定性。     

Thermal properties and fracture toughness of epoxy resins cured by phosphonium and pyrazinium salts as latent cationic initiators

In this work, the latent thermal cationic initiators triphenyl benzyl phosphonium hexafluoroantimonate (TBPH) and benzyl‐2‐methylpyrazinium hexafluoroantimonate (BMPH) were newly synthesized and characterized with IR, ¹H NMR, and P NMR spectroscopy. The thermal and mechanical properties of difunctional epoxy [diglycidyl ether of bisphenol A (DGEBA)] resins cured by 1 phr of either TBPH or BMPH were investigated. The DGEBA/TBPH system showed a higher curing temperature and a higher critical stress intensity factor than the epoxy/BMPH system. This could be interpreted in terms of the slow thermal diffusion rate and bulk structure of the four phenyl groups in TBPH. However, the decomposition activation energy derived from the Coats–Redfern method was lower for epoxy/TBPH. This result was probably due to the fact that a broken short‐chain structure was developed by the steric hindrance of TBPH in the difunctional epoxy resin. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2393–2403, 2003     

乙炔法合成醋酸乙烯催化剂载体表面羧基与羰基作用机理的研究

比较了硝酸、硫酸、过氧乙酸改性对载体比表面积、孔结构、pH值以及载体表面基团的影响. 研究了过氧乙酸(PAA)改性条件对催化剂活性的影响. 改性提高了活性炭表面羧基和羰基的含量, 由在最佳PAA改性条件下制备的乙炔法合成醋酸乙烯催化剂生产能力比未经过氧乙酸改性活性炭制备的催化剂提高了14.58%. 得到了过氧乙酸改性后活性炭表面羧基和羰基总量(m)和合成醋酸乙烯催化剂生产能力(P)之间的关系为P＝1.83＋2.26×10－3×e3.17m, 并讨论了催化剂表面羧基与羰基提高催化剂活性的机理.     

克莱森-施密特缩合反应实验设计与教学

设计了丙酮、3-戊酮和环己酮分别与苯甲醛进行克莱森-施密特缩合反应的3组实验,通过对反应结果的分析深入了解酮取代基的电子效应及空间位阻对该反应的影响。在分析实验结果时,与课堂教学中的多个知识点进行关联,达到辅助教学的目的。     

Alternating copolymers consisting of arylalkyl methacrylates. II. Effect of coil collapse on fluorescence spectra of alternating copolymers of 2-(9-carbazolyl)ethyl methacrylate and aromatic vinyl monomers

Alternating and random copolymers of 2-(9-carbazolyl)ethyl methacrylate with aromatic vinyl monomers were synthesized and their fluorescence properties were compared in good and poor solvents. Contraction of the polymer coils induced the hypochromic effect, i.e., the mutual interaction of the ground-state chromophores, but caused little quenching of their excited state. This is sharp in contrast with the vinyl-type of polymers, exhibiting large interactions in both the ground and excited states. Introduction of bulky groups on the comonomers in the alternating copolymers further suppressed these interactions. © 1996 John Wiley & Sons, Inc.     

Buffer gas additives (modifiers/shift reagents) in ion mobility spectrometry: Applications,predictions of mobility shifts,and influence of interaction energy and structure

Ion mobility spectrometry (IMS) is an analytical technique used for fast and sensitive detection of illegal substances in customs and airports, diagnosis of diseases through detection of metabolites in breath, fundamental studies in physics and chemistry, space exploration, and many more applications. Ion mobility spectrometry separates ions in the gas‐phase drifting under an electric field according to their size to charge ratio. Ion mobility spectrometry disadvantages are false positives that delay transportation, compromise patient's health and other negative issues when IMS is used for detection. To prevent false positives, IMS measures the ion mobilities in 2 different conditions, in pure buffer gas or when shift reagents (SRs) are introduced in this gas, providing 2 different characteristic properties of the ion and increasing the chances of right identification. Mobility shifts with the introduction of SRs in the buffer gas are due to clustering of analyte ions with SRs. Effective SRs are polar volatile compounds with free electron pairs with a tendency to form clusters with the analyte ion. Formation of clusters is favored by formation of stable analyte ion‐SR hydrogen bonds, high analytes' proton affinity, and low steric hindrance in the ion charge while stabilization of ion charge by resonance may disfavor it. Inductive effects and the number of adduction sites also affect cluster formation. The prediction of IMS separations of overlapping peaks is important because it simplifies a trial and error procedure. Doping experiments to simplify IMS spectra by changing the ion‐analyte reactions forming the so‐called alternative reactant ions are not considered in this review and techniques other than drift tube IMS are marginally covered.     

A Review of Temperature Influence on Adsorption Mechanism and Conformation of Water Soluble Polymers on the Solid Surface

The temperature effect on adsorption behavior of water soluble polymer and structure of its adsorption layer formed on the solid surface is presented. The main reasons for such problem explanation are wide application possibilities of stabilization-flocculation properties of polymers in many technological and ecological processes and very poor knowledge about temperature dependences of high-molecular compounds adsorption on the solid surface. To systematize the information about the effect of temperature on polymer chain conformation on the adsorbent surface the following aspects were considered: thermodynamic and physicochemical characteristics of polymer solutions, stabilization-flocculation properties of polymers in the dispersed systems, and presentation of respective experimental results. The theoretical and experimental evidence of the temperature effect on polymer macromolecule conformation on the solid surface presented in the article can contribute to better knowledge and understanding of the adsorption process at the metal oxide-polymer solution interface in the temperature function.