功能离子液体/氧化硅基多孔复合材料

利用有巨大界面特征和发达孔道结构的氧化硅基多孔材料作为功能离子液体的载体,不仅可实现离子液体的固相化从而解决均相离子液体分离难的瓶颈,而且也可增加离子液体的比表面积进而提高离子液体的使用效率和稳定性;探索结合离子液体和氧化硅基多孔材料双重优点的目标功能材料的制备及应用成为近年来的一个研究热点。本文综述了离子液体/氧化硅基多孔复合材料的最新研究进展,探讨了其合成手段的有效性,并对其应用前景进行了展望。     

固相法合成苯胺与邻甲氧基苯胺共聚物及其性能

以苯胺和邻甲氧基苯胺为单体,甲磺酸为掺杂酸,用固相法合成了甲磺酸掺杂苯胺与邻甲氧基苯胺共聚物。 通过红外光谱、紫外可见吸收光谱、X射线衍射、透射电子显微镜、循环伏安和电导率等对共聚物进行了结构表征和性能测试。 结果表明,不同摩尔比的苯胺与邻甲氧基苯胺共聚物处于中间氧化态,随邻甲氧基苯胺含量的增大,共聚物的掺杂率降低。 共聚物具有较高的结晶性和纤维状形貌,当苯胺与邻甲氧基苯胺摩尔比为1∶1时,具有较高的电化学活性,其导电率为1.65 S/cm。     

苯胺四聚体与聚乙二醇嵌段及星型共聚物的合成及表征

以氨基封端的苯胺四聚体为基础, 通过将端氨基取代为不同数量的羧基, 得到了一系列连接臂数不同的苯胺四聚体-聚乙二醇共聚物, 对反应历程中的各阶段产物进行了结构表征, 并对苯胺四聚体及最终产物进行了电化学性能测试. 结构表征证明反应按照设计路线成功进行并得到了理想的产物; 循环伏安特性曲线表明, 共聚物基本保留了苯胺四聚体的电化学性能, 可以发生从还原态到中间态再到氧化态的转变.     

Sorption of Cobalt on Modified Silica Gel Materials

Various silica gel materials were chemically modified with imidazole, diaza-18-crown-6 (DA18C6) and dibenzod-18-crown-6 (DB18C6). The degree of functionalization of the covalently attached molecule was calculated from C, H, N analysis and ranged between 0.270 and 0.552 mmol/g (for sorbents with imidazole) and between 0.043 and 0.062 mmol/g (for sorbents with DA18C6 and DB18C6). The degree of functionalization depends on the reflux time and silica gel matrix used. Experimental sorption capacity ranged between 0.038 and 0.228 mmol/g (for sorbents with imidazole) and between 0.019 and 0.050 mmol/g (for sorbents with DA18C6 and DB18C6). Synthesized hexagonal mesoporous silica matrix MCM-41 with uniform pore diameter <40 Å was used too. Change of pore diameters of silica gel support to larger pores should have a positive influence on access of cobalt ion to sorption centers to increase of sorption capacity of sorbents. The sorption kinetics of cobalt and the influence of cobalt concentration, pH of various kinds of silica gel matrix with immobilized imidazole group in static conditions on sorption were measured. The sorption of cobalt in various conditions (pH, contact time of phases) with constant liquid-solid ratio (V/m = 50 ml/g) was studied. The distribution coefficients ranged between 200 and 50 000 ml/g (for imidazole), 85 and 120 ml/g (for DB18C6) and between 230 and 500 ml/g (for DA18C6) according to silica gel matrix used and according to the method of sorbent preparation. pH plays important role in the sorption of cobalt on prepared sorbents with immobilized crown ethers due to protonization of crown ethers. Protons significantly competes to sorption of cobalt in acidic solutions. The influence of presence of other heavy or toxic metals (Hg(II), Cd(II), Mn(II), Zn(II), Cu(II), Fe(III), Cr(III), Al(III) and the influence of sodium and potassium on sorption Co(II) from aqueous solutions was investigated. Sorption of cobalt decreases in order Hg > Cu > Cd > Zn, Fe > Mn > Al, Cr. The presence of sodium and potassium ions at concentration 0.05 mol/l significantly influences on the sorption of cobalt with sorbent with immobilized DB18C6 functional group.     

An NMR Study of MeTMS Based Coatings Filled with Colloidal Silica

Coatings were prepared by mixing MeTMS and an aqueous colloidal silica. Mixing of an MeTMS hydrolysis mixture with the aqueous colloidal silica is only possible, without flocculation of the colloidal silica particles, within a certain time window. ²⁹Si NMR was used to follow the hydrolysis/condensation reactions of MeTMS, whereas ¹H NMR was used to monitor the reaction of the MeTMS monomers and oligomers with the silica surface in the coating liquid. The reaction of MeTMS with the surface of the SiO₂ particles is determined by the oligomer size. Typical SiO₂ surface coverage is less than 3 molecules/nm² (approximately one monolayer). Large MeTMS oligomers and/or cyclic species do not react with the SiO₂ surface. These species are probably too apolar to react or absorb at the SiO₂ surface. Flocculation of the aqueous colloidal silica occurs due to the low polarity of the hydrolysis mixture. The water content and the degree of condensation of the MeTMS determine the width of the time window.     

Advanced Characterization of Propylene-Based Copolymers and Olefin Block Copolymers

Summary: The newly developed interactive separation of polyolefins by high temperature liquid chromatography (HTLC) provides new information about the chemical composition distribution of polyolefin elastomers. The technique has the advantage of being quantitative in its separation, and has high resolution for the separation of polyolefins by their chemical composition without influence by cocrystallization. Chemical composition distributions can be determined for individual polymers and blends which contain the full range of comonomer typically present in polyethylene and poylypropylene homopolymers, semi-crystalline copolymers, and amorphous copolymers. HTLC analysis in combination with the other fractionation techniques, such as DSC, TREF, NMR, and xylene fractionation, can be used to estimate the amount of olefin block copolymer present in a block composite produced by chain shuttling catalysis.     

多孔球状淀粉接枝共聚物的合成及其性质研究

报道了一种多孔球状淀粉接枝共聚物的合成。此球有很强的机械性能，良好的稳定性和较高的致孔率，平均孔径约为１９．５ｎｍ，以其为载体固定化糖化酶活力为１４６２ＩＵ／ｇ干胶，比活为２９．３１ＩＵ／ｍｇ蛋白。     

Hierarchically Porous Organic Materials Derived From Copolymers: Preparation and Electrochemical Applications

Abstract

Compared to conventional porous materials with a uniform pore size distribution, hierarchical ones containing interconnected macro-, meso-, and micropores have greatly enhanced material performance due to the increased specific surface area and mass transfer. Copolymer is a good candidate used for construction of such hierarchically porous structures, resulting from its tunable segment composition, unique phase separation, and self-assembly, etc. Hierarchically porous materials derived from copolymers can be served as a versatile support for many reactive molecules. Furthermore, hierarchically porous carbon materials (HPCMs) can also be prepared by carbonization of copolymers, one segment of which is converted to carbon while the other segment is responsible for the pore formation after its removal by pyrolysis. The obtained hierarchically porous copolymers or carbon materials have promising electrochemical applications especially in energy conversion and storage. In the present review, recent advances in preparation of hierarchically porous materials (HPMs) derived from copolymers are reviewed, and their electrochemical applications in supercapacitors, lithium-ion batteries, fuel cells, electrochemical biosensors, and electrocatalysis are also introduced. The rational design and control for the hierarchically porous microstructures are described deeply from the molecular level. Also, the relationship between the micro-structure and the electrochemical performance is revealed. This review can provide us a better understanding of both theory and experiment for the preparation of hierarchically porous organic materials and their electrochemical applications.     

超细SiO2填充聚甲基乙烯基硅氧烷的动态流变特性

研究粒子填充类聚合物体系的动态粘弹响应，可在较宽应变、温度、频率范围内获得有关体系分散状态及相互作用等结构信息。用粒径小、比表面积大的二氧化硅(SiO2)增强聚硅氧烷时，其独特的化学结构和表面特性对填充体系的静态和动态流变特性有显著影响，Payne等研究了碳黑增强硫化橡胶的动态粘弹性，迄今关于SiO2增强聚硅氧烷，尤其对未硫化体系动态流变特性研究很少报道。本文以超细、高比表面积且具多孔结构的SiO2填充聚甲基乙烯基硅氧烷(Polymethylvinylsiloxane，PMVS)，对室温下不同SiO2含量的SiO2/PMVS体系动态流变特性进行了研究。     

碳化多孔有机骨架制备氮掺杂多孔碳及其气体吸附研究

通过简单的一步碳化方法, 以含氮的多孔有机骨架JUC-Z2为碳前驱物制备出氮掺杂多孔碳材料. 与原始JUC-Z2材料相比, 制备的多孔碳材料显示出明显提高的气体吸附量和增强的吸附焓. 其中JUC-Z2-900的CO₂吸附量高达113 cm³·g^-1, H₂吸附量也达到246 cm³·g^-1, 超过了大部分报道的多孔材料. 尤其是JUC-Z2-900的CH₄吸附量在273 K, 1 bar下高达60 cm³·g^-1, 据我们所知, 这一值为目前报道材料的最高值. 除此之外, 样品还显示出选择性吸附CO₂的能力, 273 K下, JUC-Z2-900的CO₂/N₂的选择性高达10, CO₂/H₂的选择性也高达66. 另外, 样品具有很高的热稳定性, 有望应用在碳捕获和清洁能源储存等领域.     

Sorption Characteristics of Pillared Ferruginous Montmorillonite Modified with Cetylpyridinium Bromide

The sorption capacity of pillared ferruginous montmorillonite modified with cetylpyridinium bromide for iodine, methylene blue, and phenol was studied. Procedures for preparing a modified sorbent with the optimal sorption power for phenol were developed.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 6, 2005, pp. 901–904.Original Russian Text Copyright © 2005 by Panasyugin, Kitikova, Bondareva, Sivak.     

（苯乙烯—丁二烯—氧乙烯）多嵌段共聚物的某些特性

本文研究了(苯乙烯-丁二烯-氧乙烯)多嵌段共聚物的相转移催化能力和与LiClO_4形成络合物的导电性能以及在高分子共混时的增容作用。结果表明,该共聚物对Williamson固-液相反应具有良好的相转移催化作用;在氯醇橡胶与ABS共混中可作为增容剂,添加3％左右,即可显著地改善共混物的力学性能;与LiClO_4形成的络合物在35℃的导电率可达4×10~(-4)S·cm~(-1)。     

非线形嵌段共聚物的合成

主要介绍了非线形嵌段共聚物,如星型嵌段共聚物、杂臂星型共聚物、梳型聚合物等的合成方法,包括多官能团引发剂法、大分子引发剂法等。各种活性聚合方法,如阳离子开环聚合、原子转移自由基聚合(ATRP)和氮氧稳定自由基聚合等都可以用于合成非线形嵌段共聚物。     

Copolymerization of Ethylene and Propylene Using Silicon Tetrachloride‐Modified Silica/MAO with Et[Ind]2ZrCl2 Metallocene Catalyst

For the copolymerization of ethylene with propylene or a higher α‐olefin, using Et[Ind]₂ZrCl₂ metallocene catalyst, modification of silica with silicon tetrachloride prior to MAO adsorption can increase the activity, which is more pronounced for ethylene/1‐hexene copolymerization at higher pressure and temperature. The molecular weight of the copolymer produced was lower and the polydispersity tends to be decreased. No significant effect of SiCl₄ addition on the microstructure and the chemical composition distribution of the copolymer produced was observed.     

Sorption Modification of Fine Silica with Polyvinylpyrrolidone

The interaction of fine silica with polyvinylpyrrolidone in aqueous medium was studied by IR spectroscopy.     

Nanoparticle Vesicles Through Self Assembly of Cyclodextrin‐ and Adamantyl‐Modified Silica

Stable nanoparticle vesicles were for the first time prepared from adamantyl‐ and cyclodextrin (CD)‐modified silica nanoparticles forming host–guest interactions in aqueous solution. Adamantyl‐functionalized nanoparticles were obtained from thiol‐isocyanate reaction of thiol‐modified nanoparticles with 1‐adamantyl isocyanate. The CD modified silica particles were isolated from a reaction of mono‐6‐para‐toluenesulfonyl‐β‐cyclodextrin with the thiol functionalized silica under microwave conditions in basic media. The obtained particles were characterized in respect of agglomeration and self‐assembly behavior in aqueous solution by dynamic light scattering and transmission electron microscopy. The found vesicle structures are exceptionally stable even after evaporation of water. Such inorganic hollow spheres formed through self‐assembly processes may be important for chemical storage and transport. The technique of chemically‐driven assembly is an attractive option to form useful complex structures by tunable agglomeration.

     

淀粉共聚物的合成与应用

本文介绍了淀粉共聚物的合成方法,包括自由基引发、阴离子引发和其它引发方法等;以及共聚物的应用范围:增稠剂、絮凝剂、粘合剂、吸水剂和上浆剂等.     

Synthesis and Characterization of pH-Responsive Block Copolymers with Primary Amine Groups

A new pH-responsive block copolymer, methoxy poly(ethylene glycol)-b-poly[5-methacrylamido-pentylamine hydrochloride](mPEG-b-PMAAPA) was synthesized and characterized in this paper. The monomer 5-methacrylamido-pentylamine hydrochloride(MAAPA) and the macroinitiator(mPEG-ACVA) were synthesized, respectively, and mPEG-b-PMAAPA was then obtained by free radical polymerization. The structure and molecular weight of mPEG-b-PMAAPA were confirmed by hydrogen nuclear magnetic resonance(¹H NMR) spectroscopy and gel permeation chromatography with multiangle laser light scattering(GPC-MALLS) measurements. At a low pH, it is hydrophilic due to the protonation of the primary amine groups. With increasing pH value, deprotonation occurs and the hydrophobicity of PMAAPA block increases. This molecular feature leads to interesting aggregation behavior of mPEG-b-PMAAPA in aqueous solutions at different pH values as revealed by dynamic light scattering(DLS) measurements, transmission electron microscopy(TEM) observations and resonance light scattering(RLS) measurements.