混合高聚物分相过程标度、分形与Monte Carlo模拟

基于光散射、Monte Carlo模拟标度理论和分形(Fractal)概念研究和分析了高分子混合体系不稳相分离过程结构函数的标度行为和成因, 结果表明相分离的形态是一种分形结构, 其分形维数不随时间变化. 结构函数的标度行为起源于相态的分形结构. 相态的分形结构是不稳相分离特征之一.     

高分子凝胶化反应的分形几何分析

据分形理论,基于实验基础上,进行了高分子凝胶化反应的分形几何行为分析,以苯乙烯-二乙烯苯凝胶化反应为例,分别由激光及小角x-光散射测定其反应中大分子重量、尺寸及散射光强角度依赖性,来定量描述化学反应及分析体系的分形行为和测定分数维D值.这种避开各种复杂的凝胶化理论,立足于现代物理技术及新理论,去剖析高分子凝胶化反应的分形几何行为,能够在更本质的深度揭示这类复杂反应的规律.     

分形表面及其性能

本文介绍了分形、分维的基本概念及分形表面的实验分析方法，评述了分形表面的性能。     

《功能高分子材料》

全书共分17章，结合功能高分子材料的结构与性能、制备方法及应用领域，对离子交换树脂，吸附树脂，离子交换纤维和活性碳纤维，高分子膜分离材料，高分子色谱固定相，高分子试剂，高分子负载催化剂，导电高分子材料，电效发光聚合物材料，非线性光学高分子材料，液晶高分子材料，感光高分子材料，医用高分子材料，环境敏感高分子材料，高分子电解质，高分子染料，淀粉，纤维素衍生物高分子等进行了详细论述。[第一段]     

关于高分子凝聚态物理学范式的思考

每门成熟科学必然都存在一个范式,体现该门学科特殊的内在结构、基本理论框架,界定研究范围.但迄今为止,发展迅猛的高分子凝聚态物理学的范式尚未形成.本文梳理、总结了近二、三十年来高分子凝聚态物理学的重要成果,阐述并强调了软凝聚态物质、自相似、分形、标度律、关联效应、溶致凝聚、熵致相变、布朗运动、多体效应和对称破缺等基本概念及其意义,指出探究和凝练高分子凝聚态物理学的范式是摆在当前高分子物理学家面前亟待解决的问题.     

两性高分子絮凝剂P(FA/NVP/DMC)处理钻井废水的研究

考查了一种两性高分子絮凝剂P(FA/NVP/DMC)对钻井废水的絮凝性能。试验显示,在pH=7、投加量为186.94mg/L条件下,CODCr去除率达到90.2%,浊度去除率达到98.9%;对钻井废水絮凝处理后的絮体进行电镜扫描,运用非线性数学分形理论计算絮体空隙分维数,结果表明,理论计算与试验结果一致。     

高分子生物材料分子工程研究进展（下）

高分子生物材料分子工程研究进展（下）林思聪（南京大学高分子科学与工程系，生物材料分子工程及控制释放分子工程室，南京，２１００９３）４体内稳定的高分子生物材料目前用于制造半永久性内植物的体内稳定高分子生物材料主要有有机硅橡胶、聚四氟乙烯、聚对－苯二甲酸...     

化学中的分形(Fractals)

本文介绍了分形、分维的基本概念,评述了酶和蛋白质分子链、表面的分形特征,酶催化动力学的分形、多重分形热力学及相变。     

可生物降解的高分子类型,合成和应用

综述了生物降解高分子的定义，实现生物降妥的主要方法和生物降解高分子主要类别，以及它们在生物医学领域及环保事业等方面的重要用途和意义。阐明了影响生物降解速度的主要因素，对控制，调节生物降解速度的订研究动态进行了介绍。     

高分子药物学的研究进展与期盼

自从20世纪70年代提出高分子前药的概念以来,伴随着纳米技术的发展,"高分子药物学"作为高分子科学和材料学、纳米科学、药物学、临床医学、分析科学的交叉学科,正在悄然形成.本文综述了近年高分子药物在药物化学、制剂学、药效学等方面所取得的进展,概述了高分子药物的药理学和药代动力学与小分子药物的区别与联系,指出了高分子药物药效学、药理学和药代动力学研究中的难题和瓶颈,特别是高分子药物可能存在的"三种状态"及从"纳米颗粒药"到"单个高分子药"再到"小分子药"的转变,分析了高分子药输送过程中存在的多重屏障如毛细血管壁、细胞外基质和细胞壁等,阐述了高分子药物的"生理靶向"和"EPR"效应的竞争,指出了高分子药在靶向输送和逆转耐药方面的优势,强调了发展相关分析方法的必要性,期盼高分子科学家与药物学家进行真诚有效的合作,大力促进我国高分子药物学和高分子药物产业的创新和发展.     

高磺化度聚苯胺体系中的分形结构研究

通过透射电镜的观察研究发现磺化聚苯胺的胶体聚集体和胶粒内部结构都具有分形体的特征 ,从而将分形的概念及其数学模型引入共轭导电聚合物体系之中 .磺化聚苯胺胶体的聚集体为很不均匀的分支状开放结构 ,其形成过程可用扩散控制集团聚集模型 (DLCA)进行模拟 ,计算机模拟生成的图形及其分形维数都与实验观测结果相当吻合 .胶粒由于是在分散介质所形成的平均化场中生成 ,屏蔽效应减弱 ,是比由它组成的聚集体要致密的球形结构 ,该结构的生成可用随机雨点模型模拟且结果相近 .     

Mathematical modeling of polymer-induced flocculation by charge neutralization

A detailed mathematical model for flocculation of colloidal suspensions in presence of salts and polymers is described and validated. In former case, the classical DLVO theory, which accounts for relevant variables such as pH and salt concentration, is incorporated into a geometrically sectioned discrete population balance model. For processes involving polymers, flocculation via simple charge neutralization is modeled using a modified DLVO theory in which the effect of adsorbed polymer layers on van der Waals attraction is included. The fractal dimension of aggregates is obtained by dynamic scaling of experimental data for time evolution of mean aggregate size. The particle surface potential is assumed to be approximately equal to the zeta potential. The model predictions are in close agreement with experimental results for flocculation of colloidal hematite suspensions in the presence of KCl and polyacrylic acid at different concentrations. In particular, given values of model parameters, e.g., Hamaker constant, fractal dimension, surface potential, and thickness of adsorbed polymer layer, the model can realistically describe the kinetics of flocculation by a simple charge neutralization mechanism and track the evolution of floc size distribution. Representative examples of sensitivity of the flocculation model to perturbations in surface potential and fractal dimension and to modification in the DLVO theory for polymer-coated particles are included.     

On the nanostructure of polymer layers formed by adsorption from binary and ternary solutions on a solid SiO2: a combined adsorption and atomic force microscopy (AFM) study

The thickness of nanolayers formed by adsorption from dilute and semi-dilute solutions on a solid SiO₂ surface has been estimated from adsorption isotherms and atomic force microscopy (AFM) measurements for polystyrene, poly(butyl methacrylate), and their mixtures. The thickness of the adsorption layers depends strongly on the adsorption conditions and is controlled by several features of the adsorbing entities. In a low-concentration regime of adsorption, the length of polymer chains and the nature of their interaction with the substrate are the most important factors controlling the adsorption process. Above the critical concentration C*, macromolecular clusters (aggregates of several overlapping chains) are formed in a solution as a result of polymer chains self-assembly. Therefore, the final adsorption layer thickness is determined mainly by the size of the clusters in this concentrated regime of adsorption. We also demonstrate that in the case of polymer mixtures, the adsorption leads to formation of mosaic structures with alternation of the polymeric components in plane of the substrate and a characteristic domain size of approximately 200 nm for each of the components. AFM study reveals that the adsorbed layers are fractal structures whose fractal dimensions depend on the type of the polymer and the adsorption process. We demonstrate therefore that the structure of nanolayers of polymers and their mixtures on the solid surface can be regulated by variation of the adsorption conditions.     

大孔交联聚苯乙烯分形结构的图像分析法研究

采用图像分析法测定大孔交联聚苯乙烯树脂的 现大孔交联聚苯乙烯的外表面具有分形结构,分形维数在２和３之间,将图像分析法测定的分形维数与小角Ｘ－射线散射法测得的结果对照。发现两种方法测定结果虽然不同,但在不同树脂之间的变化趋势是一致的,因此,可用图像分析法比较不同大孔树脂分形结构的差别。     

Fractal geometry analysis of chemical structure of natural starch modification as a green biopolymeric product

Public concerns and official pressures around environmental protection as well as exhausting petroleum resources have brought about preferences in studying and applying environmental-friendly polymers instead of synthetic petroleum-based polymers. For this aim, biopolymers can have outstanding advantages in biodegradability by saving time, energy and effort spent on increasingly costs of polymeric wastes. Natural starch (being studied in this work), as one of the most abundant natural resources for polymer materials, is inexpensive and biodegradable. As starch necessarily needs for modifications and processing before being used as ideal green polymer material, it is vital to perform feature extraction and defect detection measures in structure by some method like image analysis. Fractal as a new geometry has circumstantially progressed recently in the fields of image processing, physical space–time, medical image analysis, electrochemical patterns, digital images, sounds etc. Box Count Fractal Dimension as a very important and popular part of fractal geometry can be a useful factor in feature extraction and pattern recognition. This paper presents a new method for defect detection in the structure of natural starch modification images using the fractal dimension (FD) along with mean and standard deviation of image color. This is performed via feature extraction based on artificial intelligence by MatLab R2013a for box counting algorithms. Otsu’s graythresh method by MatLab R2013a is applied to binarize the images. The results of proposed methodology are illustrated as log–log curves where the fractal dimensions are recognized by curve fitting (CF) tool with more than 95% accuracy. The outputs express that starch samples’ FD vary in the range from 1.636 to 1.926 among which the last is identified as non-defective polymer. Non-defective feature is of great importance for quality control measures and chemical reactivity being here highlighted as biodegradability.     

Drying dissipative structures of aqueous solution of poly (ethylene glycol) on a cover glass

Macroscopic and microscopic dissipative structural patterns formed in the course of drying a series of poly (ethylene glycol) (PEG) having molecular weights ranging from 1,000 to 2×10⁶ in aqueous solution have been studied on a cover glass. The broad ring patterns of the hill accumulated with the polymers are formed irrespective of the molecular weights of PEG molecules. The single round hills are formed also in the center in the macroscopic scale, when the molecular weight is large. The characteristic convection flow of the polymers and the interactions among the polymers and substrate are important for the macroscopic pattern formation. Cross-like fractal patterns are observed, especially for the diluted solutions in the microscopic scale. These patterns are determined mainly by the electrostatic and polar interactions between the polymers and/or between the polymer and the substrate in the course of solidification. Interestingly, these microscopic patterns are reflected based on the shape and size of the PEG polymers.     

高聚物中的自相似与分形

本文主要报告分形理论在固态高聚物领域应用的最新研究成果,叙述该领域一些新进展,较详细地讨论了高分子混合物相变过程相态的自相似、分形与凝聚动力学,半结晶聚合物晶区与非晶区界面的分形散射,以及共混物界面的分形问题。     

The effect of inhomogeneous stickiness on polymer aggregation

The aggregation of polymers is important in the formation of marine aggregates and the vertical transport of material in the ocean. A polymer may be inhomogeneous along its length, with associating groups at some points along its length where bonds are more likely to form. In this paper we investigate the effects of inhomogeneous 'stickiness' along the polymer length. We describe the results of three-dimensional off-lattice simulations of polymer-polymer aggregation for four different types of polymer: polymers which are sticky along their entire length, polymers which are sticky at the ends only and two types of polymer which are slightly sticky along their entire length. We examine the mean radius of gyration and the fractal dimension of the resulting aggregates and the dynamics of aggregation. The slightly sticky polymers and the polymers which are sticky only at the ends form aggregates with a higher fractal dimension than the polymers which are sticky along their entire length. However, the mean radius of gyration of the aggregates formed by polymers which are sticky only at the ends is significantly larger than that of the aggregates formed from slightly sticky polymers. The aggregation dynamics are also different for the polymers which are sticky only at the ends compared to the slightly sticky polymers. A single 'stickiness value' is therefore likely to be inadequate to describe a polymer. We also examine the effect of polymer rigidity; it seems that the effect of inhomogeneous stickiness is greater for almost-straight polymers than for coiled chains.     

Dissipative structures formed in the course of drying an aqueous solution of poly(allylamine hydrochloride) on a cover glass

Macroscopic and microscopic dissipative structural patterns formed in the course of drying a deionized aqueous solution of cationic polyelectrolyte, poly(allylamine hydrochloride) on a cover glass have been observed. Drying times range from 40 min at 45 °C to 450 min at 5 °C, and are insensitive to the polymer concentration. Pattern area shrinks toward the center at the low polymer concentrations, and increases as the concentration increases. A macroscopic broad ring pattern, where the polymer accumulates densely, forms in many cases. Beautiful fractal patterns are observed at the microscopic scale. The fractal dimension increases from 1.2 to 1.6 as polymer concentration increases from 10^-6 monoM to 10^-2 monoM. The relative rates between the water flow at the drying front and the convection flow of water accompanying the movement of polymer are important for the macroscopic and microscopic pattern formation.     

韧性聚合物材料断面分维与断裂韧性

韧性聚合物材料断面分维与断裂韧性吕素平，漆宗能（中国科学院化学研究所工程塑料国家重点实验室，北京，１０００８０）关键词分维，断裂韧性，聚合物，微裂纹，剪切带利用分形几何定量描述材料断面的粗糙特征［１－４］为建立断面形貌与材料韧性间的定量关系提供了可能...