Derivation of Copolymer Composition Equation Through Kinetic Theory in Binary Copolymerization Systems with Antepenultimate Effect

A new treatment to characterize copolymer composition in binary copolymerization systems was developed by using a steady-state assumption for free radicals. It gives a copolymer composition equation solely through classical kinetic theory with the antepenultimate effect taken into account. This equation and its derivation procedure are compared with those previously published.     

Special Forms of Copolymer Composition Equations

A theoretical explanation is presented for the experimentally observed binary copolymer composition equations in the form of y = Kx^a, where y is the ratio of the numbers of two monomers being incorporated in the polymer, x is the number or concentration ratio of the two monomers in the feed, and K and “a” are constants characteristic of the copolymerization system. The value of “a,” found experimentally, ranges from 0 to near 4. It is shown that the composition equation of this form with a = 0, 1, 2, 3, and 4 can be obtained under various limiting conditions from the conventional copolymer composition equations which take into account the terminal and penultimate effects. This simplification is often accompanied with reduction in the order of Markovian comonomer sequence distribution statistics associated with the original standard composition equations. It is also pointed out that the conventional composition equations can account for y = Kx^a with noninteger “a” for limited experimental ranges of x.     

A New Analytical Solution of the Binary Copolymer Composition Equation and Suggested Procedure for Deriving the Monomer Reactivity Ratios

Abstract

An absolute analytical procedure is found for obtaining the parameters of the differential, binary, copolymer composition equation, setting up a least-squares condition that places equal weight on all experimental lines of the Mayo-Lewis plot. The values of monomer reactivity ratios for the system ethyl methacrylate (M₁-vinylidene chloride (M₂), studied by Agron et al., are r₁ = 2.052 ± 0.043 and r₂ = 0.346 ± 0.052. These values, especially r₁, differ from the estimates by Agron et al. The new solution, however, appears to yield the estimate of maximum likelihood for the reactivity ratios based on the given experimental data.     

Matlab在二元共聚物组成曲线绘制中的应用

通过Matlab GUI工具开发出一款专供反复使用且操作简单的绘制共聚物组成曲线的图形用户程序.其开发过程包括图形用户界面的构思、控件的绘制与调整、图形对象属性的设置、M文件的编写和程序调试与运行.该图形用户程序可实现绘图、参数显示、坐标捕捉和曲线风格设置等功能.它的使用在高分子化学教学中收到了良好的效果,通过随机输入...     

共聚物平均组成曲线软件的开发

利用高级编程语言Vc 6.0为工具,制作了高分子化学课程中的共聚物平均组成曲线的动态曲线图.曲线显示窗口主要有以下功能,即重画坐标系功能、清除当前曲线功能、清除全部曲线功能、绘制曲线功能、输入参数功能、返回登陆窗口功能.采用控件编程技术,实现了参数的随机录入、曲线的动态形成、坐标系和曲线的变色绘制、线体和线宽的重新设置以及序列显示曲线相关参数等诸多功能.它不仅可以作为高分子化学课程课堂教学使用,又可作为本专业学生有效地进行课后复习.该教学系统针对性强,操作简单,使用方便,是一种较实用的计算机辅助教学工具.     

Structural Effect and Composition of Anionic Copolymer on Protein Flocculation

Flocculation of lysozyme with anionic copolymers of acrylamide, acrylic acid, and sodium styrene sulfonate used as flocculants was performed in pursuit of high flocculation efficiency. Two major factors, pH and ionic strength, are used to investigate the relationship of the flocculation behavior of protein by copolymers and the functional group (–COOH, –NH₂, –SO₃H) compositions of these copolymers. The protein flocculation can be controlled by adjusting pH. In addition, the various copolymers exhibit differing effects on ionic strength induced protein flocculation. FT-Raman spectroscopy was applied to investigate the mechanism of interaction between protein and copolymer. An attempt was made to understand how the pH and ionic strength change the surface chemical characteristics of protein and copolymers, as well as the relationship between the structure of copolymer and the protein flocculation process.     

计算机辅助有机元素分析研究共聚物的组成

本文提出了计算机辅助有机元素分析计算高分子共聚物组成的一般公式,并以丙烯酰胺-丙烯酸钠共聚物为例予以验证。同时测试了AP-20系列共聚物及AT-430共聚物的共聚组成,其结果与~(13)C NMR测定数据一致。     

Effect of Ethylene-Propylene Copolymer Composition on Morphology and Surface Properties of Impact Poly(propylene) Copolymer

Summary: Impact poly(propylene) copolymers (IPC) having various ethylene-propylene rubber (EPR) compositions were prepared using a high activity Ziegler-Natta catalyst. EPR composition was characterized by temperature rising elution fractionation (TREF) analysis and FT-IR spectroscopy. Effect of EPR composition on the morphology and surface properties of IPC was investigated by scanning electron microscopy (SEM), 3D profiler, and gloss meter. Composition and amount of amorphous and crystalline EPR were quantified by TREF and found to be dependent on the ethylene content in EPR. From the SEM result, it was found EPR composition has a strong influence on its shape and size. IPCs containing propylene-rich EPR exhibited a finer dispersion of EPR phase. The surface roughness decreased with decreasing ethylene content in EPR. The comparison of EPR composition and morphology and surface properties exhibited strong correlations.     

聚丙烯-g-聚氨酯共聚物组成对其结晶行为的影响

接枝共聚物;聚丙烯-g-聚氨酯共聚物组成对其结晶行为的影响     

The Influence of Reaction Conditions on the Copolymer Composition in Inverse Miniemulsion

Summary: Water-soluble poly(2-acrylamido-2-methylpropane-1-sulfonic acid-co-1-vinylimidazole) (P(AMPS-co-1-VIm)) and poly(2-acrylamido-2-methylpropane-1-sulfonic acid-co-2-(dimethylamino)ethyl methacrylate (P(AMPS-co-DAMA)) are studied as it is known that the copolymer composition is affected by pH of the monomer phase in inverse miniemulsion. The distribution of the basic monomers in the continuous and dispersed phase changes due to their degrees of protonation. The amounts of the monomers in the cyclohexane phase is determined by gas chromatography, the copolymer composition is studied by elemental and thermogravimetric analysis. An insight into the monomer distribution in the polymer is provided by simultaneous potentiometric and conductometric titration of polymer solutions.     

Phase-Separation Phenomena of Copolymer Solutions and Fractionation of Copolymers by Chemical Composition

Precipitation temperature-total polymer concentration diagrams for toluene solutions of two styrene-acrylonitrile copolymers different in chemical composition and their mixtures were determined and then triangular phase diagrams of this system were constructed from these diagrams. It is speculated from the triangular phase diagrams and experimentally shown that the copolymer may be effectively fractionated by chemical composition in this system.     

氯乙烯/N-取代马来酰亚胺共聚竞聚率及共聚物组成

研究了氯乙烯(VC)与多种N-取代马来酰亚胺的溶液共聚合,求得各对单体的竞聚率.结果表明,各种马来酰亚胺的竞聚率都远高于VC的竞聚率,即N-取代马来酰亚胺单体的活性均比VC单体活性高.计算得到N-取代马来酰亚胺Q和e值.由于苯环的共轭效应,N-苯基及N-取代苯基马来酰亚胺具有较大的Q值.各对单体的e值差别较大,表明有形成交替共聚物的倾向.此外,还考察了聚合过程中共聚物组成的变化,用递推法预测了这类体系共聚物瞬时和累积组成随转化率的变化.     

Alkoxysilane Functional Acrylic Latexes: Influence of Copolymer Composition on Self-Curing Behavior and Film Properties

Reactive latexes based on acrylic polymers with trimethoxysilyl groups in the side chain were prepared by semi-continuous emulsion copolymerization. The properties of the latex film related to the polymer network structure and their evolution upon thermal curing were studied as a function of the content of the reactive comonomer, trimethoxysilylpropyl methacrylate (TSPMA), ranging between 8 and 25 wt-%. In particular, the sensitivity to both organic solvent (chloroform) and water and the thermomechanical properties were investigated by swelling experiments and dynamic-mechanical analysis (DMA). The results are interpreted in terms of a transition from uniform to microheterogeneous crosslinking regime, possibly as the result of formation of polyorganosilsesquioxane-like (POSS) crosslinking domains at higher TSPMA content.     

基于单体的Q和e值绘制二元共聚双曲线*

采用Matlab中的Plot函数,首次以单体的Q、e值为中间变量,绘制出二元共聚双曲线。将二元共聚物组成曲线F1-f1和F2-f2同时呈现在一个图上,使隐含的第二单体的共聚行为可视化,有助于加深学习者对二元共聚的理解。     

用NMR分析可生物降解的两亲性嵌段共聚物的相对分子质量和组成

凝胶渗透色谱(GPC)法是根据聚合物分子链流体力学体积大小的比较来测定聚合物相对分子质量(以下简称分子量)的,测得的聚合物分子量与聚合物分子链在溶剂中的构象有关[1]。两亲性嵌段共聚物分子链中亲水链段和亲油链段的极性差异很大,几乎在任何溶剂中它们的构象都不相同,因此可     

Copolymers of Wheat Starch and Polyacrylonitrile. Effect of Aqueous-Organic Solvent Systems on Copolymer Composition

Starch-polyacrylonitrile graft copolymers prepared in a number of aqueous-organic solvent systems with ceric ammonium nitrate as the initiator had more grafted chains than those prepared in water alone, and these were of lower molecular weight. Substitution of methanol for 80% of the water produced grafted chains with a molecular weight of 15,700 and a grafting frequency of 253 anhydroglucose units per graft. The influence of catalyst concentration, increased reaction temperature, and sodium sulfate on the composition of the copolymer were investigated for the methanol-water system.     

乙烯基单体／N-苯基马来酰亚胺共聚物组成分布测定原理及应用

共聚物分子量往往根据溶液性质来测定 ,而组成变化对高分子溶液的性质有影响 .如果共聚物组成不随分子量而变化 ,则认为组成分布均匀 .用化学或光谱方法得到的共聚物组成只是一个平均值 ,不能完全表征组成分布情况 .根据溶液性质差异进行分级 ,需选择合适的溶剂 沉淀剂体系 ,且操作时间长 .采用薄层色谱法所需时间亦长 ,且由于存在扩散效应而掩盖真实的共聚物组成分布 .自从凝胶渗透色谱 (ＧＰＣ)出现后 ,将紫外吸收光谱 (ＵＶ)或红外吸收光谱仪与示差折光仪 (ＤＲ)串联 ,一个对组成敏感 ,一个对浓度 (共聚物总量 )敏感 ,将组成变化和分子量…     

Composition and Microstructure Determination of the Syndiotactic Copolymer of para-Methylstyrene and Styrene by Pyrolysis Gas Chromatography

The composition and microstructure of syndiotactic para-methylstyrene/styrene copolymer was determined by a pyrolysis gas chromatography (Py-GC) method. This method uses the styrene and para-methylstyrene monomer peak intensities to determine the styrene and para-methylstyrene composition in the copolymer. The number average sequence length of styrene was calculated by using the triad peak intensities. Because of the low concentration of para-methylstyrene in the copolymer, the number average sequence length of para-methylstyrene was determined with formulas that incorporate the copolymer composition and the number average sequence length of styrene. The distribution of para-methylstyrene defined by the terms “percent of single units” and “percent of desired distribution” was calculated by the number average sequence of para-methylstyrene. This method has been tested with copolymers containing up to 24 mole% of para-methylstyrene. The composition results from Py-GC of para-methylstyrene and styrene copolymers used in this study were in excellent agreement with ¹H-NMR results.