文献分析软件HistCite在大学生创新项目教学中的应用

文献分析和利用是信息社会中大学生应当掌握的一项基本技能。文献可视化工具可以以直观的形式显示文献的要素,从而有助于理解和掌握文献。以指导大学生创新项目的教学为例,介绍了文献分析软件HistCite在生物质高分子碳化课题分析中的应用。采用该软件,通过对碳化领域文献进行分析,可以迅速发现该主题的主要研究机构、重要作者以及关键主题词,并绘制可视化的文献编年图,从而揭示碳化研究领域的发展趋势、热点以及科学前沿,帮助大学生快速了解该领域的发展概况。     

SYNTHESIS AND CHARACTERIZATION OF NOVEL BIPOLAR PPV-BASED COPOLYMER CONTAINING TRIAZOLE AND CARBAZOLE UNITS*

Two new blue light-emitting PPV-based conjugated copolymers containing both an electron-withdrawing unit(triazole-TAZ) and electron-rich moieties (carbazole-CAR and bicarbazole-BCAR were prepared by Wittig condensationpolymerization between the triazole diphosphonium salt and the corresponding dialdehyde monomers. Their structures andproperties were characterized by FT-IR, TGA, DSC, UV-Vis, PL spectroscopy and electrochemical measurements. Theresulting copolymers are soluble in common organic solvents and thermally stable with a T_g of 147℃ for TAZ-CAR-PPVand of 157℃ for TAZ-BCAR-PPV. The maximum photoluminescence wavelengths of TAZ-CAR-PPV and TAZ-BCAR-PPV film appear at 460 nm and 480 nm, respectively. Cyclic voltammetry measurement demonstrates that TAZ-BCAR-PPVhas good electrochemical reversibility, while TAZ-CAR-PPV exhibits the irreversible redox process. The triazole unit wasfound to be an effective π-conjugation interrupter and can play the rigid spacer role in determining the emission colour ofthe resulting copolymer.     

Novel Bipolar Conjugated Polymer Containing Both Triphenylamine and Oxadizole Units

A novel bipolar conjugated polymer containing triphenylamine and 1,3,4-oxadiazole units was synthesized by Suzuki reaction.Its structure and properties were characterized by NMR,IR,UV-Vis,PL spectroscopy and electrochemical measurement. The photoluminescent spectroscopy and cyclic voltammograms measurement demonstrated that the resulting polymer shows blue emission (477 nm) and possesses both electron and hole-transporting property.     

聚甲基丙烯酸三乙基锡酯的溶度参数和溶液性质研究

本文研究了聚甲基丙烯酸三乙基锡酯(PTETM)在二十五种溶剂中的溶解性能。测定了PTETM试样在不同溶剂中的特性粘数,估算了PTETM的三维溶度参数为:δ=18.8(J/cm~3)~(1/2);δ_d=16.8(J/cm~3)~(1/2);δ_p=6.28(J/cm~3)~(1/2);δ_h=5.73(J/cm~3)~(1/2)。并就聚合物中锡原子上的取代基对其溶解性能的影响进行了讨论。作者还订定了PTETM在四氢呋喃溶液中,25℃时的MHS方程为[η]=2.55×10~(-3)M_w~(0.691);在甲苯溶液中,30℃时的MHS方程为[η]=2.79×10~(-3)M_w~(0.662)。利用Burchard-Stockmayer-Fixman关系,由四氢呋喃体系(25℃)和甲苯体系(30℃)所求得的Flory特征比C_∞=9.4。     

共轭聚合物材料及电致发光器件

共轭聚合物是一种极有应用前景的有机半导体材料,本文综述其研究进展,包括典型共轭聚合物材料PPV、PT、PF等及PPP的工作原理,发展前景和存在的问题。     

导电高分子材料的应用和进展

论述了复合型及结构型导电高分子材料的导电机理、应用和研究进展。     

Orthogonal surface-grafted polymer gradients: A versatile combinatorial platform

Orthogonal polymer brush gradients are assemblies of surface-anchored macromolecules, in which two material properties of the grafted chains (e.g., grafting density, molecular weight) vary independently in orthogonal directions. Here, we describe the formation and applications of two such orthogonal assemblies, involving: (1) molecular weight and grafting density (MW/σ) gradients of a given polymer and (2) molecular weight gradients (MW1/MW2), of two different polymers. Each point on orthogonal gradient substrate represents a unique combination of the two surface properties being varied, thus facilitating systematic investigation of a phenomenon that depends on the two said properties. We illustrate this point by employing orthogonal structures to study systematically: (1) formation of polymer brush-nanoparticle composite assemblies, (2) protein adsorption and cell adhesion, and (3) chain conformations in tethered diblock copolymers exposed to selective solvents. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3384–3394, 2005     

含氟硅聚合物的合成及应用

含氟硅聚合物作为一种新型材料,有机结合了含氟聚合物和含硅聚合物的优点,成为材料领域研究开发的热点之一。本文综述了含氟硅聚合物合成的研究进展,介绍了其应用情况。     

Polymers as drugs—Advances in therapeutic applications of polymer binding agents

Polymer drugs are those in which a polymer agent has a direct therapeutic effect on the body. A major investigated area of polymer drugs is their use as binding agents, or sequestrants, which can neutralize or remove undesired components from the body. By taking advantage of the unique properties of crosslinked, insoluble polymers, new polymer drugs continue to be developed for oral use, acting in the gastrointestinal tract and excreted in the feces. Soluble polymer binders may be administered by a variety of routes and act at diverse sites of therapeutic action. This article reviews the properties of polymer drugs, particularly sequestrants, with an emphasis on recent advances in polymer properties which may enhance the utility of this class of drugs. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3146–3157     

Computer-aided method for simultaneous determination of substances in solution by spectrophotometry

A computer program, LESSDAD (East-Squares Spectrophotometric Determination by Absorbance Data), is described for computation of the best set of analytical concentrations of two ligands and/or metal ions from absorbance measurements. A least-squares method is used to calculate the concentrations from the pH of the solution, spectrophotometric data (experimental absorbances and known molar absorptivities) and the relevant equilibrium constants. The Newton-Raphson iteration is used to solve the mass-balance equations. The program is rapid and convenient to use and gives satisfactory results on a number of systems.     

A BASIC program for least-squares estimation of the parameters influencing line shapes in multi-site chemical exchange in nuclear magnetic resonance spectrometry

The OPTAO program in BASIC solves modified Bloch equations and calculates the line shape for a given set of parameters, which are then optimized by a Gauss-Newton non-linear least-squares method to provide the best fit to experimental data. Up to five sites can be handled. The program is suitable for personal computers.     

导电性聚西佛碱的研究：Ⅰ含硫聚西佛碱的合成,性能及表征

采用对氯苯甲醛和联苯二胺为原料,合成了4,4′-二氯代苄叉联苯胺,发现该化合物具有热致液晶性。利用所合成的二氯代化合物与硫化钠在醋酸锂催化下缩取得得到了含硫聚西佛碱探讨了高分子量含硫聚西佛碱的合成方法。测出该含硫聚西佛碱具有3.4×10~(-11)S/cm本征导电率。使用红外光谱、元素分析等方法表征了所合成的聚合物。     

Synthesis and fabrication of highly functionalized Jeffamine antimicrobial polymeric coating

A simple, robust, and eco‐friendly technique for the fabrication of functionalized Jeffamine polymer in an aqueous medium is developed. The polymer is prepared by post polymerization modification of Jeffamine ED‐2003 of molecular weight 2000. The structure of the modified polymer was studied in detail using FTIR and NMR (¹H and ¹³C NMR) spectroscopic methods. The thermal properties and degradation of the polymer were examined by DSC and TGA techniques. The polymer exhibited glass transition temperature (T_g) at 115°C. The functionalized polymeric compound showed good antimicrobial activity against gram‐negative bacterium Escherichia coli, a tubercular variant Mycobacterium smegmatis, and gram‐positive bacterium Staphylococcus aureus with a zone of inhibition of 6 to 12, 9, and 5 to 9 mm diameter, respectively. The compound also showed good activity against the fungus, Candida albicans, with a zone of inhibition of 6 to 11 mm diameter. The morphology of the polymer films and interaction of the microbes with functionalized Jeffamine polymer were investigated by using scanning electron microscopy (SEM).     

环糊精与聚合物的包合作用

本文着重介绍了环糊精及其衍生物与聚合物所形成的各种包合物,并扼要介绍了它们的研究和应用前景。     

两亲性笼型倍半硅氧烷（POSS）杂化高分子的自组装

笼型倍半硅氧烷（POSS）是一种由si-O-si键构成的高度对称笼型结构、端基具有极高的可设计性及高反应性新型有机一无机杂化材料,空间尺寸1～3nm;选取带有特定结构的光、电、磁等特性单元,利用活性聚合的方法可制得不同形状的POSS-Polymer杂化材料,通过溶剂、热、电、纳米印刷等方法“梳理”分子链结构,使之成为长程有序的纳米序列结构材料,获取具有预期结构和功能特性的高分子实体。本文从分子自组装的角度对两亲性笼型倍半硅氧烷（POSS）杂化高分子材料进行了介绍,分析了其在生物医药用高分子、智能高分子及低介电高分子材料等多个领域内的最新研究进展,并对今后的发展做了相关的预测与展望。     

一类新型的呈树状支化的合成高分子

树状支化高分子是一类近几年中新出现的高分子化合物.本文介绍了这类树状分子的发展与现状以及它们在结构、性能方面的特点;对这一领域内几位主要研究者,包括Dow化学公司Tomalia博士、South Florida大学Newkome教授、Cornell大学Frechet教授的工作做了简要的评述,同时对这类化合物在合成与应用方面的前景做了一些初步的讨论.     

An Overview of Important Microstructural Distributions for Polyolefin Analysis

Summary: Polyolefins with complex microstructures are becoming increasingly common in academic and industrial applications. Polyolefin analytical techniques are evolving to provide a more detailed picture of these microstructures, with the development and improvement of hyphenated-techniques and cross-fractionation methods. These modern analytical techniques provide a wealth of information on polyolefin microstructure and, despite being extremely useful, they can also be hard to interpret without the help of mathematical models that link polymerization kinetics to chain microstructure and polymer characterization results. In this paper we review some of the most important distributions for polyolefin microstructure and derive a few new expressions that help understand the results obtained with several polyolefin characterization techniques.     

Template-Free Self-Assembly of Two-Dimensional Polymers into Nano/Microstructured Materials

In the past few decades, enormous efforts have been made to synthesize covalent polymer nano/microstructured materials with specific morphologies, due to the relationship between their structures and functions. Up to now, the formation of most of these structures often requires either templates or preorganization in order to construct a specific structure before, and then the subsequent removal of previous templates to form a desired structure, on account of the lack of “self-error-correcting” properties of reversible interactions in polymers. The above processes are time-consuming and tedious. A template-free, self-assembled strategy as a “bottom-up” route to fabricate well-defined nano/microstructures remains a challenge. Herein, we introduce the recent progress in template-free, self-assembled nano/microstructures formed by covalent two-dimensional (2D) polymers, such as polymer capsules, polymer films, polymer tubes and polymer rings.     

Modification of Particle Filled Polymers with High Energy Electrons Under In-Stationary Conditions of Melt Mixing

Summary: Polymer modification with high energy electrons is well-established in polymer industry and used for degradation, cross-linking, grafting, curing, and polymerization. These applications use local and temporal precise input of energy in order to generate excited atoms or molecules and ions for subsequent molecule changes via radical induced chemical reactions. In the present study, high energy electrons have been used to modify polyolefine (polyethylene and polypropylene) systems in presence of a grafting agent under stationary and in-stationary conditions. Polymer modification with high energy electrons under stationary conditions characterizes a process where required absorbed dose is applied to polymers in solid state and at room temperature. Polymer modification with high energy electrons under in-stationary conditions is a novel process where required absorbed dose is applied in molten state during melt mixing process. In this novel process, the penetration depth of electrons is limited to a part of mixing volume. The total mixing volume is modified due to the change of polymer mass within the penetration depth of electrons during mixing process. A 1.5 MeV electron accelerator has been directly coupled to a banbury mixing chamber in order to study this novel process. In comparison to the stationary process, the main differences are working at higher temperature, absence of any crystallinity, intensive macromolecular mobility as well as intensive mixing during dose application. The influence of both processes on mechanical properties and flame resistance of polymer composites is discussed.