聚合物流动行为的光散射表征

简要地介绍了光散射原理及目前光散射技术在聚合物流变学的中的应用，归纳并分析了前人的一些主要工作成果。对于一些至今难以解释的实验现象提出了自己的一些认识，并对仍未有人涉足的振动力场下聚合物复杂流动光散射表征提出了新的设想。     

聚合物乳液研究中的静态和动态激光光散射技术

介绍了静态和动态激光光散射技术及其在聚合物乳液中测试所依据的基本理论和应用方法。总结了激光光散射技术在应用时的实践经验与技术     

光散射技术及其在化学与化工领域中的应用

对近十几年来光散射技术在化学与化工领域中的应用进行综述,着重介绍分散体中各相的形态结构的表征和凝胶化过程、高分子聚合、无机胶体体系的聚集等动态过程的研究进展,并简单介绍光散射技术的发展简史和基本原理     

光测力学在表征聚合物应力场中的应用

简介了光测力学的应用和基本原理,对光散射技术原理及其应用进行了说明,详细阐述了光测力学在聚合物流场应力表征中的应用,尤其是对光测力学表征挤出机口模的狭缝流场的方法和光测力学在聚合物电磁塑化挤出流场中的应用进行了详细说明,介绍了光测图象处理技术,如图像增强、模式识别等,并且展望光测力学在新型聚合物电磁动态成型机理方面作出贡献。     

激光光散射法测定粒度在陶瓷行业中的应用

本文介绍了激光光散射法测量粒度的原理,以及激光粒度分析仪的特点,并探讨了激光光散射法测量粒度在陶瓷生产中的应用。     

光散射测量技术在聚合物共混体系中的应用

首先介绍了聚合物共混体系混炼效果的传统表征方法,并分析了其局限性,在此基础上,对近年来逐步应用于聚合物多组分流变行为表征的光散射理论作了简要说明,概述了光散射在共混体系中相分离机理、相图以及形态学方面的应用,归纳分析了前人的一些主要工作成果,并对利用光散射测量振动力场下聚合物的混炼效果提出了自己的设想.     

聚合物分子量的测试与表征

聚合物分子量表征聚合物研究的关注重点之一。测定高分子聚合物分子量的方法主要有端基滴定法、蒸汽压渗透法、超离心沉降法、粘度法、凝胶色谱法、激光光散射法和场流技术等。文章对各种聚合物分子量的分析方法及其应用作了较详细的介绍,并比较了他们的特点和适用范围,对几种常用的方法作了重点介绍,并对近年来新兴起来的微量凝胶色谱和场流技术等新方法做了展望。     

盐酸阿霉素共振光散射法测定酵母RNA

pH 8.69条件下,酵母RNA的加入使盐酸阿霉素的共振光散射信号强烈增强,在322与558 nm处产生两个共振散射峰。研究表明,在322 nm波长处共振光散射强度与酵母RNA的浓度在0.02~20μg/mL范围内呈良好的线性关系,检出限为2.3 ng/mL。该方法用于样品中RNA的测定,结果令人满意,由此建立了一种选择性好、灵敏度高的RNA共振光散射分析方法。     

LED照明用聚碳酸酯基光散射材料的研究

以聚碳酸酯(PC)为基材,分别选用无机光散射剂BaSO4、SiO2和有机光散射剂聚甲基丙烯酸甲酯(PMMA),研究不同种类和含量的光散射剂对PC力学性能、透光率和雾度的影响.结果表明,光散射剂的加入对试样的拉伸强度影响较小,对缺口冲击强度影响较大.通过调节光散射剂的种类和用量,可以有效调节PC复合材料的透光率和雾度.当...     

激光光散射法测定PNIMMO的相对分子质量及其分布

介绍了火药用黏合剂PNIMMO(端羟基聚3–硝酸酯甲基–3–甲基氧杂环丁烷)的相对分子质量及其分布测定的激光光散射法。该法以四氢呋喃为流动相,通过MZ–gel SD plus凝胶色谱柱、示差折光检测器与多角激光光散射仪联用,获得了样品的相对分子质量及其分布,并对谱图进行分析讨论。结果显示,激光光散射法不依赖于标样,可直接测定PNIMMO的相对分子质量及其分布,快速简便,结果可靠,对于PNIMMO合成工艺的改进和后处理方法的选择具有指导意义。     

Absolute online monitoring of a stepwise polymerization reaction: Polyurethane synthesis

The feasibility of using a recently introduced method for continuous, absolute online monitoring for step‐growth polymerization was demonstrated, and polyurethane synthesis was chosen for the demonstration. The previously reported use of this method was for monitoring free‐radical initiated chain‐growth polymerization. The technique involves continuously withdrawing a small stream of reaction liquid from the polymerization reactor and pumping it through a series of light scattering and viscosity detectors. This permits the absolute weight‐average molecular weight and reduced viscosity to be simultaneously monitored as the reaction proceeds. The final weight‐average molecular weights of the polyurethane samples were compared to the separate light scattering measurements of the final products. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2070–2077, 2001     

Water‐soluble star polymers with a phthalocyanine as the core and poly(ethylene glycol) chains as branches

Uncharged water‐soluble phthalocyanines (Pc's) and some metallophthalocyanines (Me‐Pc's) were prepared by means of a chemical modification of a commercial Pc or by a cyclic tetramerization reaction starting from 4‐nitrophthalonitrile derivatives. The necessary hydrophilicity for the water solubility of these Pc derivatives was achieved by the binding of eight 9‐methoxytriethyleneoxy branches on peripheral Pc positions or, alternatively, four or eight linear poly(ethylene glycol) methyl ether (PEGME; weight‐average molar mass = 350 or 750 g/mol) units. The chemical structure of these products was characterized by ¹H‐NMR and matrix‐assisted laser desorption/ionization–time ‐of ‐flight mass spectrometric analysis. Finally, their solutions were examined by ultraviolet–visible and luminescence spectroscopy and dynamic light scattering experiments. All of the samples were water soluble, although the formation of small aggregates was ascertained by dynamic light scattering measurements. Furthermore, a lower scattered light intensity was measured for Pc derivatives with longer PEGME branches, which, probably playing a more negative role in the self‐assembly process, hindered the aggregation phenomenon. Preliminary data on their sensing ability are also reported. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Solution properties of polyaniline

Solution properties of polyaniline (PANI) synthesized at various temperatures were studied using static light scattering (SLS), intrinsic viscosity, and dynamic light scattering (DLS). We demonstrated that average radius of gyration 〈R_g〉, intrinsic viscosity [η], and average hydrodynamic radius 〈R_H〉, of polyaniline molecules in dilute N‐methyl‐2‐pyrrolidinone (NMP) solutions increased with decreasing synthesis temperatures, i.e.; increasing molecular weight. SLS data demonstrate that second virial coefficient (A₂) decreased with increasing particle sizes suggesting that solubility of PANI in NMP decreased with increasing particle sizes. We also find that the polymers extend as the polymer concentration is lowered and that the increase in the hydrodynamic radius can be expressed by a power law of the electrostatic screening length. This behavior is typical of polyelectrolytes in dilute solution, providing a basis for understanding the conformation changes of this metallic polymer in solution. Copyright © 2009 Society of Chemical Industry     

反式聚异戊二烯的溶液性质——Ⅱ.用光散射法研究含有微凝胶的溶液性质

分别用 Gruber、Lange法和大角外推法处理了反式聚异戊二烯溶液的光散射数据,并将所得结果与渗透压、粘度和GPC法的分析结果进行了分析、比较。结果表明,用Gruber法得到的各试样溶胶的重均分子量和微凝胶的含量比较合理。     

Static and dynamic light scattering studies of the crystallization of poly(ethylene oxide) from dilute solutions

We have monitored in situ the self-seeded crystallization of poly(ethylene oxide) from dilute toluene solutions by dynamic light scattering. In supercooled dilute solution, the radii (R) of the crystals grow linearly with time. the rate constant obtained from the slope of the plot R versus time depends on the temperature and the molecular weight of the polymer, both of which determine the degree of the supercooling. The maximum crystal size obtained from solutions of fixed concentration also depends on the temperature and the polymer molecular weight. It appears that crystal growth is limited because of molecular weight fractionation. Static light scattering from suspensions of stable crystals provides information on the crystal morphology. A comparison of experimental and theoretical particle scattering functions suggests that the crystals form short cylinders and that the crystal growth from the seeds is primarily two-dimensional. Some comparisons to melt crystallization are possible. The preparation and use of tiny seed crystals is critical to the success of these studies.     

Distribution analyses of multi-modal dynamic light scattering data

A method of data analysis for dynamic light scattering is proposed to evaluate the weight fraction, w(R_h), of a small amount of large aggregates in a dilute solution, where R_h is the hydrodynamic radius. We examined the time-correlation function of scattering intensity for model multi-modal systems, i.e., mixtures of latex solutions having different particle sizes and of polystyrene standard solutions having different molecular weights, by properly taking into account the unknown fractions, w(R_h), and scattering intensities of individual components. We derived an equation to evaluate the weight fractions of the components. The validity of this method was verified by successfully reconstructing the observed correlation functions having fast and slow modes. As a demonstration, the fraction of aggregates in a thermosensitive polymer solution in water was evaluated as a function of temperature.     

激光散射在生物高分子中的应用

本文综述了激光散射在生物高分子中的应用,着重以蛋白质为例分析了激光散射在表征生物高分子的分子量、尺寸、构象、缔合、聚集、结晶和分形等方面的重要作用,同时对它在生理分析上的应用作了简要介绍。     

LED灯罩用光扩散聚碳酸酯材料

聚碳酸酯基光扩散材料是良好的工程材料,被广泛应用于各领域。PC基光扩散材料作为LED照明匀光灯罩材料已经受到重视。文章介绍聚碳酸酯基光扩散材料的制备方法,散射体粒子在制备过程中的影响因素及研究现状,并展望PC基光扩散材料的研究方向。