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从高分子运动的温度依赖关系看高分子运动特点 总被引:1,自引:0,他引:1
高分子的运动是高分子科学中最为基本、最为重要的问题之一,也是教学的重点之一,它是联系高分子微观结构与高聚物宏观性能之间的桥梁,本文就高分子运动的特点尤其是高分子运动的温度依赖关系进行了讨论,进而从本质上理解高聚物结构与性能之间的关系. 相似文献
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在"高分子物理"课程教学中,主要难点是教学内容比较繁杂,所涉及的概念很多且较抽象,各种高分子材料的结构和性能差异性大,不易把握其共性。以高分子结构、性能和分子运动的中间态,即高分子链的远程结构中分子链的形态、高聚物性能的高弹性和链段运动为基础,避开繁杂抽象的具体概念,以简洁的方式来呈现高分子物理的教学内容,帮助学生在渐进的教学过程之初便建立一个形象化的整体性思路,以此作为后续教学的指导性思路,在整个教学过程中进一步展开和强化,教学效果很好。 相似文献
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"高分子物理"(在中国科学技术大学叫"高聚物的结构与性能")和"高分子物理实验"课是该校高分子科学与工程系本科生的必修课。为了讲好和全面建设这两门课,作者倡导并积极开展教学研究,发表39篇教学研究论文,作者把这些研究心得和成果及时引入教学中,先后编写和出版了十几本教材及教学参考书,教学质量不断提高,并逐步形成了有鲜明特色的教学,在国内高校产生了很好的影响。通过多方面的建设,2005年"高聚物的结构与性能"被评为国家级精品课程,2006年"高分子物理实验"被评为安徽省精品课程。 相似文献
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中国科学技术大学开设"高聚物的结构与性能"课程已有50年历史,2005年该课程被评为国家级精品课程(主持人:何平笙),同年,"全面提升高分子物理重点课程的教学质量"获国家级教学成果二等奖(第一完成人:何平笙).为了全面体现获奖成果的内容,何平笙教授在常年教学经验基础上,总结出教学研究心得,并结合高分子物理最新研究成果,编写了<新编高聚物的结构与性能>教材,于2009年9月由科学出版社正式出版发行. 相似文献
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高聚物发光方法的进展 总被引:2,自引:0,他引:2
高聚物发光方法研究迄今只有十几年的历史,而其应用几乎已广泛深入到高分子科学的各个领域。尤其在高聚物构象、形态及动态方面的?究已取得显著成功。高聚物发光方法是以高分子链所固有的、或向高分子体系引入的发光“探针”(probe)或 相似文献
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关于《高聚物的结构与性能》课的教学主线 总被引:1,自引:5,他引:1
关于《高聚物的结构与性能》课的教学主线何平笙(中国科学技术大学材料科学与工程系,合肥,230026)《高聚物的结构与性能》课,许多院校也称之为《高分子物理》课。顾名思义,是包括以高聚物为对象的全部物理学内容的课程,往往给人以内容庞杂的印象。加之该学科... 相似文献
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《高分子科学》2019,37(12):1298-1304
Interlocked-ring polymers, also known as polycatenanes, possess an interesting molecular architecture. These polymers are composed of many interlocked rings in a linear chain. The topological constrain between neighboring rings distinguishes the interlockedring polymer from its linear counterpart. Here we present extensive molecular dynamic simulations on the interlocked-ring polymers and analyze the static properties of the polymer. By applying external forces to the polymer, we also study the force-extension curves of the polymer, which provides rich information about the mechanical properties of the interlockedring polymers. 相似文献
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通过6-氯-5,12-萘并萘醌(1)与酚醛树脂经亲棱取代,一步合成制备具有光致变色性的酚醛树脂(3)。在苯溶液中,光致变色聚合物(3)与光致变色化合物6-{4-[2-(4-羟基苯基)异丙基]苯氧基}-5,12-萘并萘醌(2)有相似的光致变色行为。但是,在聚合物(3)中,由于苯基处于聚合物骨架中不易迁移,使聚合物(3)的变色速度较化合物(2)明显减慢,化合物(2)的光异构化速度常数是聚合物(3)的3倍。同时发现溶剂对聚合物(3)的光诱导trans-ana异构化反应速度有明显影响,在氯仿中的反应速度常数约为在苯中的2倍。 相似文献
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Eric Janiaud Eric Janiaud Antoine Chateauminois Christian Fretigny 《Journal of Polymer Science.Polymer Physics》2011,49(8):599-610
The effects of repeated large strain shear cycles on the dynamics of a glassy acrylate polymer are investigated using an original contact method. It is based on the measurement of the shear properties of thin (about 50 μm) polymer films geometrically confined within contacts between elastic substrates. Under small amplitude (300 nm–10 μm) oscillating lateral displacements, friction at the contact interface can be neglected and the measurement of the contact lateral response thus provides information about the rheology of the sheared polymer film. Using this approach, the complex shear modulus of the polymer film can be measured both in the linear (viscoelastic) and in the nonlinear regimes. The investigations are focused on the changes in mechanical properties induced in a large strain regime where the polymer glass is cyclically sheared up to the yield point. During the application of large strain cycles, the mechanical response of the polymer glass slowly evolves toward a quasi stabilized state which is described from the measurement of an apparent–strain dependent–complex shear modulus. When the applied strain is increased by a tenfold factor, this apparent shear modulus decreases by about one decade. These underlying changes are investigated from a consideration of the time dependent linear viscoelastic properties after the mechanical stimulus. Both mechanical rejuvenation and recovery (ageing) effects are evidenced. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011 相似文献
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银/聚合物纳米复合材料 总被引:2,自引:0,他引:2
银/聚合物纳米复合材料是一种典型的聚合物基复合材料, 其结构和性能依赖于合成方法,因此开发材料的优异性能必须以深入研究纳米材料的先进合成技术为前提。本文综述了纳米银粒子及其与聚合物形成的纳米复合材料的最新合成进展, 重点介绍了基于液相化学还原方法合成纳米银粒子的新方法, 如溶胶-凝胶法、沉淀法、微乳液法和离子液体法, 以及纳米银粒子的分散技术和原位法合成银/聚合物纳米复合材料的新技术, 并介绍了纳米银复合材料的电绝缘性、表面增强拉曼散射性能、抗菌性及其在生物医学等领域中的应用。 相似文献
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Glucoamylase was immobilized onto novel porous polymer supports. The properties of immobilized glucoamylase and the relationship
between the activity of immobilized enzyme and the properties of porous polymer supports were investigated. Compared with
the native enzyme, the temperature profile of immobilized glucoamylase was widened, and the optimum pH was also changed. The
optimum substrate concentration of immobilized glucoamylase was higher than that of native enzyme. After storage for 23 d,
the immobilized glucoamylase still maintained about 84% of its initial activity, whereas the native enzyme only maintained
about 58% of the initial activity. Moreover, after using repeatedly seven times, the immobilized enzyme maintained about 85%
of its initial activity. Furthermore, the properties of porous polymer supports had an effect on the activity of the immobilized
glucoamylase. 相似文献
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Copolymers of oligo(oxyethylene) methacrylates and a series of polar comonomers, i.e. acrylamide, acrylonitrile and maleic anhydride, were synthesized as media for dual- or single-ion conduction, and correlation between polymer structure and properties was established through detailed studies on polymer morphology, mechanical property and the ion transport process. Polar groups in the polymer chain sequence were found to enhance matrix polarity and to retard oligoether crystallization, as well as to raise chain rigidity. Therefore, both novel dual- and single-ion conduction are realized, with a simultaneous improvement in the mechanical properties of polymer materials. An investigation about the effect of matrix polarity on the ion transport process is also carried out, making use of the concepts concerning polymer segmental relaxation. Hence the enhanced matrix polarity is found to contribute to the improvement in ion conduction, mainly through its promotion of salt dissociation. However, at high temperature this facilitation is counteracted due to the “anomalous” temperature-dependence of salt dissociation in the polymer matrix, and the higher the matrix polarity, the more drastic is the drop in carrier number with rising temperature. 相似文献
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A. Nikakhtar A. Nasehzadeh G. A. Mansoori 《Journal of the Iranian Chemical Society》2006,3(2):185-190
The effects of the mechanical properties of DNA, such as bending, twisting, and bending-twisting interactions on the thermodynamic stability of DNA-dendronized polymer nanoclusters with different conformations in terms of free energy are investigated. The effect of temperature on the free energy is also studied and the values of enthalpy and entropy of the solution of the nanocluster are predicted. The obtained thermodynamic quantities help us to have a better understanding about the mechanical properties of DNA and the stability of the nanocluster in gene therapy. 相似文献
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结晶性芳香聚酯高压结晶行为研究进展 总被引:2,自引:0,他引:2
运用高压极限手段研究聚合物的结构、形态和性能是20世纪60年代以来兴起的一项聚合物前沿课题。本文主要结合作者自己的研究工作,重点叙述聚对苯二甲酸乙二醇酯(PET)的高压结晶行为研究,包括温度、压力、时间及分子量对PET高压结晶行为的影响,高压结晶PET的形态。以及对PET伸直链晶体结晶机理的探讨,同时简要介绍了对其它结晶性芳香聚酯诸如聚对苯二甲酸丁二醇酯(PBT)及聚对萘二甲酸乙二醇酯(PEN)的高压结晶行为研究,反映了该领域的研究概况和最新进展。并对今后的研究提出了展望。 相似文献
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A full literature and patent account (about 100 references) is given on work describing vinyl polymerization to form the homopolymer poly(norbornene). The interest in vinyl‐poly(norbornene) is driven by its dielectric and mechanical properties for the technical application as an interlevel dielectric in microelectronics applications. For comparison, the norbornene/olefin copolymerization is discussed also. The metal catalysts are introduced and important polymer product properties are emphasized. The six possible isomers for stereoregular poly(norbornene) are presented. 相似文献