两亲性海藻多糖在乳化和分散中应用的研究进展

海藻多糖是一种天然的凝胶多糖，其分子链上原生的亲水、疏水基团赋予其天然的两亲性，能够在一定程度上改善非均相之间的界面相容性，具有天然凝胶网络结构的海藻多糖还可在溶胶体系中有效阻止分散相之间的再聚集，因而海藻多糖在乳化及分散中具有极佳的应用潜能。本文介绍了海藻酸盐、岩藻多糖、卡拉胶、琼脂、石莼多糖等常见海藻多糖的化学组成、结构与性质, 并从其糖基单元上的羧基、硫酸酯基等亲水基团与甲氧基、乙酰基、蛋白质等疏水基团构成的两亲性结构出发，总结了两亲性结构对海藻多糖分子构型、表面活性及流变性质的影响，进而综述海藻多糖两亲性结构在乳化和分散中的应用。同时，还总结了通过物理或化学手段增强海藻多糖两亲性能的相关研究，例如带电疏水粒子的静电耦合、长碳链疏水化合物的化学接枝等，介绍了衍生化海藻多糖在乳化和分散中应用的研究进展，并对海藻多糖界面吸附活性增强的方向进行了展望。     

Stimuli-responsive tertiary amine methacrylate-based block copolymers: Synthesis,supramolecular self-assembly and functional applications

In the past decade, responsive polymers exhibiting reversible or irreversible changes in physical properties and/or chemical structures in response to external stimuli have been extensively investigated. Among them, tertiary amine methacrylate-based block copolymers represent a unique category considering their responsiveness to multiple external stimuli (e.g., pH, temperature and salts), which are essentially relevant to the biological milieu. These intriguing properties allow for their applications in a variety of fields ranging from drug or gene delivery, imaging, diagnostics, antibacterial coatings, catalysis, and bio-separations. This review article highlights tertiary amine methacrylate-based block copolymers, focusing on recent advances in the synthesis of tertiary amine methacrylate-based block copolymers with varying chemical structures and chain topologies, their supramolecular self-assembly in aqueous media as well as in the bulk state, and the emerging functional applications.     

高分子碳系自由基引发剂及其应用

介绍了碳系自由基引发剂的结构，热分解性能和作用机理，以及它们在功能性工程塑料的制备，高分子改性，粘合剂和阻燃材料方面的应用。     

Sintering of lunar regolith structures fabricated via digital light processing

Architectural and functional structures composed of lunar regolith-simulant CLRS-2 were fabricated via digital light processing and sintered at 1100 °C and 1150 °C under an air or argon atmosphere. This work is to investigate effects of atmosphere and temperature on mechanical properties, microstructure, and chemical composition of lunar regolith products. Samples sintered at 1150 °C in air underwent the highest sintering shrinkage and showed the best mechanical properties, likely due to the formation of glassy phase and dense structure following sintering. Conversely, argon-sintered samples exhibited lower density resulting from the lack of glassy phase. Phase analysis revealed varying chemical composition and therefore different underlying reaction mechanisms under two sintering atmospheres, indicating that sintering atmosphere significantly influences the microstructure and macroscopic properties of lunar regolith products.     

特种丙烯酸酯单体的研究进展

丙烯酸酯单体大致可分为通用丙烯酸酯单体和特种丙烯酸酯单体。特种丙烯酸酯单体因具有特殊的官能团、化学结构或特定元素而具有许多优异性能,广泛应用于涂料、油墨、粘合剂、纺织和造纸等诸多领域。本文系统综述了特种丙烯酸酯单体的分类方法、主要品种及其结构与性能特点,重点讨论了特种丙烯酸酯单体的3种合成技术及新型催化剂体系,并对有代表性的几类特种单体的合成方法做了详细介绍,同时对国内特种丙烯改酯单体的研究开发提出了建议。     

功能化纳米碳酸钙母料的制备与表征

采用溶液聚合法分别制备了表面包覆有载体树脂、复合弹性体和环氧基团的P型和H型功能化纳米碳酸钙母料,并对两种母料的产率、化学结构和热性能进行了研究.结果表明:纳米CaCO3表面的复合包覆层含有弹性体、载体树脂和将来可与PET端基发生反应的环氧基团.由于载体树脂种类的差异,导致两种母料的热分解起始温度Tdo不同,其中,H型母料的热稳定性略高于P型母料,但是,不同的载体树脂对母料的产率没有明显影响.     

化学分析分馏过程对生物质焦炭物理化学结构的影响

化学分析分馏过程广泛应用于碱金属及碱土金属对生物质焦炭活性影响的研究。针对化学分析分馏过程对生物质热解焦炭物理化学结构产生的影响展开深入研究。通过压汞仪、扫描电子显微镜(SEM)对化学分析分馏过程中焦炭的孔径分布、孔隙率、比表面积及颗粒表面形貌等物理结构的变化进行了分析,结果表明该过程对焦炭的孔隙率影响显著,对比表面积影响不大,对热解焦炭多孔状表面形貌影响较为突出。利用X射线光电子光谱法(XPS)和拉曼光谱法(Raman)对焦炭表面碳氧活性官能团结构及焦炭芳香环结构等化学结构特征展开了研究,结果表明化学分析分馏过程对生物质焦炭表面碳氧活性官能团结构的破坏作用较小,化学分析分馏对焦炭的芳香环结构影响不大,水洗过程对焦炭内部的交联结构影响不明显,醋酸铵溶液、盐酸对焦炭内部的交联结构破坏明显。     

Photophysical characterization of triazole-substituted coumarin fluorophores

The photophysical properties of fluorochromes are directly influenced by their chemical structure. There is increasing interest in chemical strategies that provide controlled changes to the emission properties of biologically compatible fluorophores. One strategy employed is the conversion of a fluorophore-attached alkyne to a triazole through a copper-catalyzed Sharpless-Meldal reaction. In this study, we have examined a series of structurally related coumarin fluorophores and evaluated changes in their photophysical properties upon conversion from alkyne to triazole forms. Ethynyl-coumarin structures showed increases in quantum yield (ca. 1.2- to- 9 fold) and bathochromic shifts (up to 23 nm) after triazole formation. To extend these results, we tested the ability of time-dependent density functional theory (TD DFT) to predict the observed changes in fluorophore absorption properties. We found excellent correlation between the predicted absorption values and experiment, providing a useful tool in the design of new fluorogenic probes.     

Multi-featured epoxy composites filled with surface-modified PTFE powders treated by Na-naphthalenide system

This study aimed to produce new multi-featured epoxy composites that are advanced in terms of mechanical properties, wear and impact resistance, and glass transition and heat deflection temperatures. Epoxy composites filled with chemically surface-treated poly (tetrafluoroethylene) (PTFE) powders at various ratios were prepared to obtain these improved properties. The chemical treatment was carried out via a Na-naphthalenide system. After this treatment, the x-ray photoelectron spectroscopy results presented the existence of functional groups such as OH, carbonyl groups, and CC unsaturation points on the surface of the PTFE powders. On the PTFE surfaces, while the atomic ratios of carbon and oxygen were substantially increased, the fluorine ratio presented a significant decrease after the chemical treatment. However, the wear rates of the novel composites were highly advanced despite this large decrease in the fluorine ratio on the surface of the PTFE powders. Moreover, functional groups such as OH, carbonyl groups, and CC unsaturation points and spongelike or network structures on the PTFE surfaces provided the opportunity to obtain strong adhesion and interfacial bonding between the surface-modified PTFE powders and the matrix. Strength and modulus values showed substantial enhancement besides the IZOD impact resistance. All glass transition and heat deflection temperatures were also substantially improved.     

Chemical Chaperones Modulate the Formation of Metabolite Assemblies

The formation of amyloid-like structures by metabolites is associated with several inborn errors of metabolism (IEMs). These structures display most of the biological, chemical and physical properties of protein amyloids. However, the molecular interactions underlying the assembly remain elusive, and so far, no modulating therapeutic agents are available for clinical use. Chemical chaperones are known to inhibit protein and peptide amyloid formation and stabilize misfolded enzymes. Here, we provide an in-depth characterization of the inhibitory effect of osmolytes and hydrophobic chemical chaperones on metabolite assemblies, thus extending their functional repertoire. We applied a combined in vivo-in vitro-in silico approach and show their ability to inhibit metabolite amyloid-induced toxicity and reduce cellular amyloid content in yeast. We further used various biophysical techniques demonstrating direct inhibition of adenine self-assembly and alteration of fibril morphology by chemical chaperones. Using a scaffold-based approach, we analyzed the physiochemical properties of various dimethyl sulfoxide derivatives and their role in inhibiting metabolite self-assembly. Lastly, we employed whole-atom molecular dynamics simulations to elucidate the role of hydrogen bonds in osmolyte inhibition. Our results imply a dual mode of action of chemical chaperones as IEMs therapeutics, that could be implemented in the rational design of novel lead-like molecules.     

Natural polyphenols as versatile platforms for material engineering and surface functionalization

Polyphenols, the ubiquitous secondary metabolites of plants, are an important part of human diet and are essential for plant functions. They have attracted considerable interest due to their important biological activities as well as intriguing chemical and physical properties. Polyphenols allow a whole panoply of chemical and physical interactions with interesting molecules and surfaces to be established. Thus, polyphenols can serve as versatile building blocks for the preparation of various functional materials, such as capsules, antibacterial and antioxidant films, micro/nanoparticles, membranes, electronic and energy storage materials, hydrogels, and cell encapsulants, with fascinating structures and properties. In addition to their important roles in engineering of functional materials, they also emerge as pivotal components in the construction of versatile surfaces, including antifouling, antibacterial, antioxidant, cell adherent and proliferable, enzyme-immobilized, patternable and peptide-embedded surfaces. This review will describe the main interactions/reactions involving polyphenols for the design of functional materials and the construction of versatile surfaces. This review will also illustrate and discuss current applications of polyphenols in material and surface sciences.     

非均相茂金属催化剂载体的研究进展

文章介绍了茂金属催化剂载体的研究新进展,着重介绍了无机载体和有机载体用于茂金属催化剂负载化的研究现状。分别陈述了无机和有机载体的一些常见载体类型,例如硅胶载体和聚苯乙烯载体;并对比了无机载体和有机载体的颗粒形态,强度,表面基团等物理化学性质的差异。研究表明,载体材料本身结构及其物理化学性质对聚合活性,聚合物形态和堆积密度有着直接的作用。进一步探索载体的结构性能与聚合动力学的关系,将对对进一步提高聚合活性,改善聚合物颗粒形态具有深远的意义。     

化学工程的多层次结构

进入21世纪前后,学界将化学工程看作一种复杂系统,企图在高层次组织化学工程的知识基础,为此不断在寻找易于进入化工复杂系统研究的切入点。文章从业已见到的颗粒群在流态变化时形成的不同几何结构以及由此而开拓的多尺度分析,来揣测化学工程的其他结构,特别是面对产量少、价值高的功能材料,企图建立化工复杂系统多层次结构的研究平台。除了基于时空多尺度的化工多层次结构外,作者认为还可以考虑基于科学内涵的历史多层次结构,以及基于人力和资金投入为尺度的运转多层次结构。     

一维贵金属纳米材料的控制合成与应用

一维纳米材料具有优良的尺寸效应,一维贵金属材料表现出不同于相应块体材料的特殊物理化学性能。本文以一维贵金属纳米结构的合成方法和机理为探讨重点,总结了近年来国内外用于控制合成一维贵金属纳米材料的主要方法,包括模板法、多元醇还原法、化学电沉积法以及金属催化还原法。着重以金属银、钯为例,介绍了其形状可控的一维纳米结构的生长机理,并以金、银等一维纳米材料为例介绍了其一维纳米结构在功能材料以及生物医学等领域的应用前景。指出建立一维金属纳米结构制备科学的新理论、新方法及其成核生长动力学模型是进一步研究的方向。     

Surface-initiated controlled polymerization as a convenient method for designing functional polymer brushes: From self-assembled monolayers to patterned surfaces

Surface-functionalization mediated through “grafting from” methods is of considerable interest as means to tailor the chemical and physical properties of functional substrates in a reliable way. The resulting polymer brushes, obtained by a “grafting from” strategy, are composed of grafted polymer chains tethered from one of their extremities to a surface by a covalent bond. Tuning the molecular parameters of these polymeric brushes such as the nature of monomer, the grafting density, and the chain length as well as the design of micropatterned structures enables delicate modification of the properties of these substrates, paving the way to the development of functional surfaces. In this review, we highlight recent and most important approaches to form monolayers and to subsequently elaborate homogeneous and heterogeneous coatings of polymer brushes by surface-initiated polymerization. The control of initiator molecule assembly is particularly important for the final configuration of polymer brushes. We report the creation of homopolymers and block copolymers using major controlled polymerization techniques as well as lithographic techniques aiming at the design of polymeric (micro- or nano-) patterns.     

“自下而上”化学合成纳米石墨烯的研究进展

纳米石墨烯是组成石墨烯结构的一部分,尺寸一般介于1~100 nm,可以作为结构单元构筑石墨烯、碳纳米管和富勒烯等功能碳材料。纳米石墨烯具有一定的量子效应、边缘效应和界面效应,在新型分子电子器件、传感器等领域有着巨大的应用潜力。本文重点介绍“自下而上”化学合成纳米石墨烯的方法、含七元环或八元环特殊结构的纳米石墨烯、杂原子掺杂的纳米石墨烯以及纳米石墨烯的边缘修饰。探讨了不同合成方法的优势和特点,介绍了不同结构纳米石墨烯的性能及应用前景,概括了“自下而上”合成纳米石墨烯存在的问题及未来的发展趋势。     

产品工程学--化学反应工程的新拓展

分析了当今化学工业的发展趋势：正由生产规模的大型化向产品结构与性能的多样化转变。指出化学反应工程的主要研究目标应从追求时空效率和物能利用的最大化向以产品结构和性能的可控化方向拓展。阐述了化学产品工程研究的核心内容：结构与性能关系、结构的制造与表征，提出化学产品各层次形态结构的形成与稳定应成为化学反应工程研究的另一条主线。     

One-dimensional extended lines of divacancy defects in graphene

Since the outstanding transport properties of graphene originate from its specific structure, modification at the atomic level of the graphene lattice is needed in order to change its electronic properties. Thus, topological defects play an important role in graphene and related structures. In this work, one-dimensional (1D) arrangement of topological defects in graphene are investigated within a density functional theory framework. These 1D extended lines of pentagons, heptagons and octagons are found to arise either from the reconstruction of divacancies, or from the epitaxial growth of graphene. The energetic stability and the electronic structure of different ideal extended lines of defects are calculated using a first-principles approach. Ab initio scanning tunneling microscopy (STM) images are predicted and compared to recent experiments on epitaxial graphene. Finally, local density of states and quantum transport calculations reveal that these extended lines of defects behave as quasi-1D metallic wires, suggesting their possible role as reactive tracks to anchor molecules or atoms for chemical or sensing applications.     

In situ synthesis and characterization of poly(2,5-benzoxazole)/multiwalled carbon nanotubes composites

This article reports the synthesis of poly(2,5-benzoxazole)/multiwalled carbon nanotubes (ABPBO/MWNT) composites by in situ polycondensation and their chemical and physical properties. The functional groups yielded from the surface modification of MWNTs by hydrochloric acids have been demonstrated to participate in the polymerization and thus led to the composites with homogenous dispersion of carbon nanotubes. The chemical structures and morphology of the afforded polymer composites have been fully characterized by FTIR, WAXD, UV-vis, TGA and SEM. The ABPBO/MWNT composites exhibit excellent thermal stability and greatly improved mechanical properties. The tensile modulus and tensile strength of the composites are 47% and 83%, respectively, higher than those of the polymer matrix. The dielectric constant of the composites is also significantly enhanced from 4 of the polymer matrix to 65 with the incorporation of 5 wt% MWNTs.     

表面化学改性吸附用活性炭的研究进展

活性炭表面官能团和杂原子的种类与数量多少决定了活性炭的表面化学性质，而化学性质决定了活性炭的化学吸附特性。通过进行表面氧化、还原以及负载增加或者消除某些基团和活性中心，可以大大改善活性炭对特定吸附质的吸附能力。文章简要介绍了活性炭表面存在的官能团、杂原子和化合物，并对近年来国内外在吸附用活性炭表面化学改性方面的进展进行评述。