阳离子聚丙烯酰胺水分散液的合成研究

概述了分散聚合的特点及其机理,重点介绍了以水为介质的阳离子聚丙烯酰胺分散聚合研究进展。详细探讨了阳离子聚丙烯酰胺水分散聚合体系的组成,即单体、分散介质、分散剂、引发剂等因素对分散聚合的影响以及各组分之间的相互关系。     

己内酰胺聚合反应工程CAD软件包——Ⅰ.工业化生产实际值与软件包计算结果的比较

介绍了己内酰胺聚合反应工程 CAD软件包的建立 ,用工厂单 VK管聚合和两步法聚合生产工艺验证了该软件包的可靠性。通过计算可得到单体转化率、聚合物聚合度、相对粘度、相对分子质量分布、环状二聚体含量、反应潜热等重要参数在聚合管中的变化情况     

聚偏氟乙烯树脂的合成

综述了乳液聚合法和悬浮聚合法合成PVDF树脂的反应原理、工艺流程,并进行了这两种合成方法优缺点的比较。     

端基滴定法和核磁共振法测定聚磷酸铵聚合度的比较

分别采用端基滴定法和核磁共振法对所合成的聚磷酸铵聚合度(n)进行了分析测试,发现两种方法对同一样品分析结果存在很大的差异。通过对两种方法的分析原理和分析测试过程的比较,认为端基滴定法不适合测定平均聚合度高的聚磷酸铵,而核磁共振法可以测定任意聚合度的聚磷酸铵,核磁共振法简便,快速,准确。     

One‐shot radical polymerization of vinyl monomers with different reactivity accompanying spontaneous delay of polymerization for the synthesis of double‐network hydrogels

Double‐network hydrogels were conveniently synthesized by the one‐shot radical polymerization of an ionic monomer for the first network and a non‐ionic monomer for the second network in the presence of crosslinkers by simultaneous addition of the monomers, that is, one‐shot and spontaneous two‐step polymerization accompanying the delay of polymerization of a second network monomer. We analyzed the polymerization process based on the conversion of each monomer during the reaction in the absence of crosslinkers. Then we fabricated the double‐network hydrogels using several polymerization systems consisting of a conjugated monomer and a non‐conjugated monomer in the presence of the dual crosslinkers. We analyzed the swelling, mechanical and viscoelastic properties of hydrogels synthesized by one‐shot radical polymerization to confirm the production mechanism and the network structure of the hydrogels. © 2020 Society of Chemical Industry     

阳离子光引发剂研究进展

阳离子型光引发剂是一类新型的紫外光固化材料的引发剂。本文介绍了阳离子光引发剂的主要种类及各自的特点 ,讨论了其光引发机理 ,并简述了阳离子光引发剂的的发展概况和主要用途。     

反相微乳液聚合制备丙烯酰胺类聚合物微球的研究进展

反相微乳液聚合技术具有稳定性好、固含量高、聚合速率快等优点而成为研究热点。本文系统地综述了近年来国内外应用反相微乳液聚合制备丙烯酰胺类聚合物微球的研究进展,概述了微乳液的基本理论及其特征,对稳定微乳液的制备进行了讨论;着重归纳了丙烯酰胺类的反相微乳液聚合,详述了聚合体系各组分的选择,同时探讨了影响聚合反应的因素,认为应研究新型表面活性剂以实现高单体浓度的聚合;介绍了聚合物微球在油田应用中提高采收率方面的应用现状。最后指出了其在深部调剖堵水领域存在的问题,以离子液体代替传统聚合体系组分制备集智能性、复合性、多功能性等综合性能于一体的聚合物微球是其未来发展方向之一。     

The nature of the organoaluminum compound and the kinetic heterogeneity of active sites in lanthanide‐based diene polymerization

The influence of the organoaluminum compound on the kinetic heterogeneity of active sites in lanthanide‐based diene polymerization was investigated. It was found that the heterogeneity of investigated catalytic systems was shown in the existence of four types of active centers. They were formed at the beginning of the polymerization process and produced macromolecules with lengths that were definite for each type of active center. The nature of the organoaluminum compound greatly influenced the kinetic activity of the polymerization centers. A method for analyzing the curves' maximums of distribution on kinetic activity and the change in kinetic activity of every type of active centers is proposed. This method allows calculating the concentration values for each type of active center separately. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 674–685, 2003     

紫外光固化胶粘剂组成与应用

介绍了自由基、阳离子和混合光固化体系,其中重点论述了自由基光固化胶粘剂的组成以及各组分对胶粘剂性能的影响,并对胶粘剂分子设计的概况作了简单说明。     

缩短PVC糊树脂聚合周期新工艺在48m~3聚合釜中的应用

简要介绍了缩短PVC糊树脂聚合周期的小、中试及 48m3釜的工业化试验过程 ,确定了适宜的聚合工艺条件及引发剂、链调节剂的用量 ;采用该技术生产后使H型PVC糊树脂的聚合周期平均缩短了3 .7h ,使生产效益提高了 14.5 %。降低了单位产品的固定折旧、制造费用及管理费用     

The influence of the nature of organoaluminum compound on kinetic heterogeneity of active sites in lanthanide‐based diene polymerization

The influence of organoaluminum compound on kinetic heterogeneity of active sites in lanthanide‐based diene polymerization was investigated. It was shown that heterogeneity of investigated catalytic systems was displayed in the existence of four types of active centers. They are formed at the beginning of the polymerization process and produce macromolecules with lengths that are definite for each type of active centers. The organoaluminum compound's nature greatly influences the kinetic activity of polymerization centers. The method of analysis of the curves' maximum distribution on kinetic activity and the change of kinetic activity of every active centers' type were proposed, which permits the calculation of values of concentration for each type of active center separately. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 358–368, 2003     

乳液聚合成核阶段的模拟与分析

建立了乳液聚合成核阶段的Monte Carlo模型，并用计算机对一个体积为10^-17m^3的微型反应器中苯乙烯的乳液聚合进行了模拟。以计算机生成随机数作为自由基被胶束和乳胶粒捕获的几率，模拟了在微型反应器中每一个自由基的生成、被胶束或乳胶粒捕获的过程以及每一个乳胶粒的生成及增长过程。通过对每一个乳胶粒在增长过程中各参数的统计计算，研究了乳液聚合成核阶段诸参数(乳胶粒数目、乳胶粒直径与粒径分布、单体转化率、聚合反应速率等)与乳化剂浓度[S]及引发剂浓度[I]的关系。结果表明，苯乙烯的乳液聚合体系中乳胶粒数目与[S]^0.5996[I]^0.4016成正比：在成核阶段乳胶粒直径分布先变宽后变窄，乳液聚合过程中乳胶粒直径分布有自动变窄的趋势；成核阶段持续时间t12与[S]^0.60[I]^0.60成正比，成核阶段结束时的单体转化率X12与[S]^1.20[I]^0.20成正比。     

影响氯乙烯悬浮聚合生产能力的主要因素及提高措施

根据氯乙烯悬浮聚合生产PVC树脂的工艺特点,分析了影响聚合生产能力的主要因素,并提出通过缩短聚合反应时间、聚合辅助时间,提高单釜产量等措施来提高聚合釜的生产能力。     

无皂乳液制备PMMA动力学及其模型

以甲基丙烯酸甲酯(MMA)为单体、过硫酸钾(KPS)为引发剂进行无皂乳液聚合反应,考察了单体MMA浓度、引发剂KPS用量及聚合温度对其动力学行为的影响。建立了转化率-时间关系曲线的模型函数———Gamm a积分函数,用它拟合了转化率-时间关系曲线,获得了聚合过程的重要特征参数,如平均成核速率,聚合最大速率和平稳期平均聚合速率及成核结束和聚合进入完成期对应的转化率。同时对聚合速率与以上各聚合参数的关系数据进行了非线性拟合,得到了它们之间的关系式。拟合相关系数非常接近于1,平均拟合误差很小,成核结束时转化率在15%以内,聚合速率随以上参数增大而增大,反应温度在聚合过程中起决定作用。     

Low-density polyethylene vessel reactors: Part I: Steady state and dynamic modelling

By the use of a perfectly mixed model and an imperfectly mixed one for lowdensity polyethylene vessel reactors, we show that increases in the initiator consumption with polymerization temperature are due to mixing limitations at the initiator feed. With all its parameters independently estimated, the imperfectly mixed model provides an excellent agreement with experimental data for several initiators, feed flow rates and polymerization pressures. In the temperature region of industrial interest for each type of initiator, the open-loop reactor dynamics drastically change from open-loop unstable, at low temperatures, to open-loop stable at high polymerization temperatures.     

聚α-烯烃减阻剂的合成研究

以TiC13/AlEt2Cl为引发体系,采用本体聚合法引发长链α-烯烃聚合,制备高减阻性能的油溶性减阻剂(DRA)。考察了各项因素对聚合反应的影响,最终确定最优化工艺条件。减阻剂环道减阻测试的结果表明,聚合物在环道中添加的质量浓度为10 ppm时,减阻率高达45.8%。     

Particle kinetics and physical mechanism of microemulsion polymerization of octamethylcyclotetrasiloxane

In the present study, the particle kinetics and physical mechanism of microemulsion polymerization of octamethylcyclotetrasiloxane (D₄) were investigated by using dodecyldimethylbenzyl ammonium bromide (DBDA) as a surfactant and n-pentane as a cosurfactant. The light transparence of the emulsion, oil-water interfacial tension and the polymerization conversion as functions of the polymerization time were recorded. Furthermore, the particle sizes and their distributions in the process were measured by using dynamic light scattering technique (DLS). The results show that there does not exist constant-rate reaction period during the polymerization. The results of DLS show that the microemulsion polymerization can be distinguished as four steps, namely (I) the dispersion period, (II) the colloid formation and reaction period, (III) the colloid reaction period, and (IV) the agglomeration period. Corresponding physical models for each period were discussed. It has been found that the nucleation occurs mostly in the swollen-micelles and the polymerization occurs mostly in the new microlatex particles for the microemulsion polymerization of D₄.     

Mixing in Viscous Polymer Reactors

Mixing is a common, but poorly understood, operation in the chemical industry. In the case of polymers, high viscosity and non-Newtonian rheology add to the complexity of designing and selecting an optimal agitator. Furthermore, the polymerization can be carried out in a single phase (as in the solution or bulk polymerization of styrene) or in multiple phases (as in the emulsion or suspension processes for PVC). Since the mixing problems are differ-ent in each type of polymerization process, the agitator requirements will be different, too.     

Photoinitiation of multifunctional acrylates via ferrocene-alkyl chloride charge transfer complexes

The propensity for ferrocene-alkyl chloride charge transfer complexes (CTCs) to photoinitiate free-radical polymerization of multifunctional acrylates was determined using photodifferential scanning calorimetry. Also, the effects of varying ferrocene (ferrocene, methoxyferrocene, and cyanoferrocene) and alkyl chloride (dichloromethane and benzyl chloride) derivatives were evaluated with regard to the overall polymerization rate and conversion. Furthermore, relative polymerization rates of traditional free-radical Type I and Type II photoinitiators were compared to those of the ferrocene-alkyl chloride CTCs. Semi-empirical quantum mechanical analysis of the complexation reaction was performed using PM3, indicating a thermodynamic preference of complexations involving benzyl chloride, and corroborated the reported complexation mechanism. In order to explain the varying polymerization rates, the association constants for each complex were determined, whereupon complexation of each ferrocene derivative with dichloromethane was found to be more facile than similar complexation with benzyl chloride due to steric considerations. Substituent effects were more pronounced for the benzyl chloride complexes relative to those involving dichloromethane where steric constraints caused deviation from the expected effect. Thus, the cyanoferrocene-benzyl chloride CTC was determined to be the most effective photoinitiator examined with regard to semi-empirical analysis, complexation kinetics, and polymerization rate. Presented at e|5: UV and EB Technical Expo and Conference, sponsored by RadTech International North America, May 4, 2004, Charlotte, NC.