KINETICS OF RADICAL POLYMERIZATION IN A STARVED FEED REACTOR (Ⅱ)──KINETICS OF METHYLMETHACRYLATE POLYMERIZATION

对“饥饿”反应器中甲基丙烯酸甲酯（MMA）聚合行为进行详尽研究,建立了聚合动力学模型,模型中考虑了由于初级自由基与单体反应生成单体自由基时所消耗的单体量;考虑了PMMA的高温解聚作用;考虑了体系中的凝胶效应,并将链终止速率常数与凝胶效应联系起来,反映在模型中．通过实验,优化回归求取了模型参数．     

“饥饿”反应器中自由基聚合动力学(Ⅱ)──甲基丙烯酸甲酯聚合动力学

对“饥饿”反应器中甲基丙烯酸甲酯（MMA）聚合行为进行详尽研究,建立了聚合动力学模型,模型中考虑了由于初级自由基与单体反应生成单体自由基时所消耗的单体量;考虑了PMMA的高温解聚作用;考虑了体系中的凝胶效应,并将链终止速率常数与凝胶效应联系起来,反映在模型中．通过实验,优化回归求取了模型参数．     

碳化硅/炭黑悬浮体中丙烯酰胺单体自由基聚合的研究

采用2种引发体系引发碳化硅／炭黑悬浮体中丙烯酰胺单体的自由基聚合，通过测定单体聚合的热效应对丙烯酰胺单体的自由基聚合过程进行了表征，并分析了丙烯酰胺单体在碳化硅／炭黑悬浮体中的聚合机理。发现炭黑的存在不仅可以加速过硫酸铵分解，而且对丙烯酰胺单体的自由基聚合具有较强的阻聚作用，造成碳化硅／炭黑悬浮体聚合诱导期过短和单体聚合转化率较低。采用氧化还原引发体系可以提高单体转化率并实现单体聚合，但无法延长单体聚合的诱导期。通过在碳化硅／炭黑悬浮体中添加不同用量的缓聚剂乙酰丙酮，可以显著改善单体的聚合特性，不仅可以随意控制单体聚合的诱导期，而且还可以提高单体聚合的转化率，从而保证了碳化硅／炭黑悬浮体的凝胶注模工艺的实施。     

伴有水解缩合反应的种子乳液聚合动力学(I)模型

伴有水解缩合反应的自由基种子乳液聚合反应是制备有机-无机杂化乳胶粒的一种新方法，水解缩合反应和自由基聚合这两种反应在乳液体系中的动力学耦合过程决定了聚合产物的微结构和应用性质。通过单体的分配系数建立了单体在乳液体系中各相的分配模型，进而建立了考虑单体分配的自由基种子乳液共聚合的动力学模型。针对功能基团在乳液各相中水解缩合反应的特点，结合自由基种子乳液共聚合的动力学模型，建立了伴有水解缩合反应的自由基种子乳液聚合动力学模型。该模型反映了反应过程中的物质传递规律、非均相反应特点、自由基共聚合和水解缩合反应间的耦合关系。     

聚丙烯固相接枝丙烯酸聚合动力学及其接枝聚合速率模型

基于自由基固相接枝聚合的终止反应主要是自由基单基终止反应的假设提出了相应的聚合机理,并建立了聚合速率模型,聚合速率与引发剂浓度呈1次方、与单体浓度呈小于1次方关系,与聚合温度服从Arrhenius关系.实验考察了聚丙烯固相接枝丙烯酸体系聚合温度、引发剂浓度、单体浓度与初始接枝聚合速率的依赖关系,这一关系与上述速率模型十分吻合.采用无约束非线性优化方法得到了各参数的全局最优解：频率因子为6.868×10⁹,表观活化能为58.89 kJ•mol^-1,单体浓度的幂为0.78.     

伴有水解缩合反应的种子乳液聚合动力学(Ⅰ)模型

伴有水解缩合反应的自由基种子乳液聚合反应是制备有机-无机杂化乳胶粒的一种新方法,水解缩合反应和自由基聚合这两种反应在乳液体系中的动力学耦合过程决定了聚合产物的微结构和应用性质.通过单体的分配系数建立了单体在乳液体系中各相的分配模型,进而建立了考虑单体分配的自由基种子乳液共聚合的动力学模型.针对功能基团在乳液各相中水解缩合反应的特点,结合自由基种子乳液共聚合的动力学模型,建立了伴有水解缩合反应的自由基种子乳液聚合动力学模型.该模型反映了反应过程中的物质传递规律、非均相反应特点、自由基共聚合和水解缩合反应间的耦合关系.     

拟三元自由基交联共聚合统计动力学模型与模拟

以甲基丙烯酸甲酯 /二甲基丙烯酸乙二醇酯自由基交联共聚合为研究对象 ,考虑到单烯与双烯自由基交联共聚合过程第 3种双键———悬挂双键的影响 ,在低双烯单体用量下简化为拟三元自由基共聚合 ,引入具有Arrhenius性质的交联影响因子 ,建立拟三元自由基交联共聚合动力学模型 .经自由基本体和溶液共聚试验验证了拟三元自由基交联共聚合动力学模型 ,通过数值仿真讨论了平均交联密度随转化率的变化关系 ,比较了本体共聚和溶液共聚条件下平均交联密度的变化规律     

结构粘结剂的配方

<正> 美国罗特公司提供了一种两份分装的粘结剂体系,可在室温下通过自由基聚合而固化。能粘结多种基体,包括金属和塑料。该剂有二部分:①含有可进行自由基聚合的不饱和单体和自由基源;②含有可进行自由基聚合的不饱和单体和用以激活自由基源的活     

含氯聚合物的制备方法

提供与普通聚合法相比分子质量分布范围窄的聚氯乙烯等含氯聚合物的简单制备方法。它是将含氯单体用活性自由基聚合法聚合，来制备聚氯乙烯等含氯聚合物的方法。而活性自由基聚合方法有２种，１种是卤素原子转移型活性自由基聚合法，另１种是将稳定的氮氧自由基作为自由基终止剂的活性自由基聚合法。     

苯乙烯溶液聚合过程变量仿真与优化研究

由于经典动力学模型的复杂性和精确性，对于预测自由基聚合过程中单体转化率一直是一个挑战。本研究通过响应面法的中心复合设计（CCD）模型进行实验设计、建模和工艺优化，研究了以丙酮为溶剂的苯乙烯溶液聚合过程中单体转化率的变化。建立的优化条件为：反应时间30 min，反应温度120℃，引发剂浓度为0.113 5 mol/L，单体转化率为76.82%，观察得到的转化率为70.86%。从而得到了一个非常适合于常规工业使用的预测单体转化率的鲁棒模型。     

稀土钕催化剂上丁二烯气相聚合过程研究

在２升的卧式双轴自清洁型搅拌床反应器对负载型稀土催化剂催化的丁二烯气相聚合过程进行了实验研究。考察反应温度和压力等因素对聚合速率和分子量及其分布的影响。确定了合适的反应条件并获得了有关的动力学参数。     

A Mathematical Model for Emulsion Polymerization

Experimental studies of emulsion and suspensoon polymerization of styrene at 50~C are reported.Amathematical model for a batch emulsion polymerization in a unbaffled reactor with stirrer is proposed.This model allows for not only the effect of adsorption of the emulsifier onto the monomer droplets butalso the gel-effect.Data from the suspension polymerization tests are used to determine the relationshipbetween K_t and X_p Conclusion of these data in the model provided a good prediction of the number andsize of the latex particles and the conversion rate over most of the conversion range.     

Polymerization of diallyl dimethyl ammonium chloride in inverse emulsion. I. Kinetics and mechanism

An aqueous solution of diallyl dimethyl ammonium chloride was dispersed in an isoparaffinic liquid. A mixture of sodium di-2-ethyl-hexyl sulfosuccinate and sorbitan monooleate was used as emulsifier. The polymerization was initiated by an oil soluble azo initiator and conducted in a stirred tank reactor at constant temperature. The initial rate of polymerization can be expressed as following in the region studied: A kinetic model is presented by which the rate of polymerization can be calculated up to high conversions by considering gel effect and initiator decomposition. Based on experimental results the loci of polymerization are assumed to be the micelles and latex particles. The polymerization mechanism is conform to the Smith-Ewart mechanism. The influences of ion strength and partition equilibria on the rate of polymerization were studied and are considered to be the causes of the 3rd order with respect to the monomer concentration.     

Computational Fluid Dynamics Study of a Styrene Polymerization Reactor

The computational fluid dynamics (CFD) approach was adopted to simulate benzoyl peroxide (BPO)‐initiated styrene polymerization in a laboratory‐scale continuous stirred‐tank reactor (CSTR). The CFD results revealed the effects of non‐homogeneity and the short‐circuiting of the unreacted styrene and initiator on the reactor performance. The study also investigated the effects of the impeller speed and the residence time on the conversion and the flow behavior of the system. The CFD simulation showed that intense mixing remained confined to a small region near the impeller. With increasing impeller speed, it was found that the perfectly mixed region near the impeller expanded, thus reducing non‐homogeneity. Different contours were generated and exhibited the effect of the mixing parameters on the propagation rate and styrene conversion. The monomer and initiator conversions predicted with the CFD model were compared to those obtained with a CSTR model. The CFD model accounts for the non‐ideality behavior of the polymerization reactor, and hence conversion predictions are more realistic.     

Continuous dosing of fast initiator during vinyl chloride suspension polymerization: Polymerization rate and PVC properties

Continuous dosing of a fast initiator during the suspension polymerization of vinyl chloride has been carried out in a pilot‐scale reactor. The kinetics course of this polymerization and the particle features of the resulting grains were discussed and compared to the conventional polymerization with the same conversion and maximum reaction rate. It was found for the system used that a suitable dosage trajectory allows the reaction rate to remain constant during polymerization. This decreases the polymerization time up to 53% compared with the conventional suspension polymerization, while the molecular weight distribution and molecular weight of the final grains remained almost unchanged. SEM micrographs revealed that PVC grains prepared using this polymerization process had irregularly shaped, uneven particle surfaces and larger particle sizes. The grains also featured high porosity with loosely aggregated smaller primary particles that led to low levels of residual unreacted monomer. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44079.     

界面聚合制备复合膜过程的数学模型

基于高分子物理化学、质量传递和相分离成膜理论,研究在复合膜制备过程中采用界面聚合反应成膜的机理,建立了非稳态条件下反应．扩散联合控制的数学模型;通过有针对性地简化,该模型可适用于反应控制和扩散控制。模型中无量纲参数有明确的物理意义,较好地反映了界面聚合反应成膜过程的机理。无量纲化处理使模型解析解形式更为简单、实用,模型与实验数据吻合良好,且优于现有模型。通过模拟计算,可得出单体(A组分)浓度、膜的厚度、膜厚增长率随时间的变化关系,并可考察聚合反应速率常数、单体(A组分)在复合层中的扩散系数、单体初始浓度等参数对成膜过程的影响．理论结果可用于指导界面聚合反应成膜实践。     

Hexafluoropropylene plasmas: Polymerization rate–reaction parameter relationships

Plasma polymerization generates thin, pinhole-free, and highly adhering films and is often described by the ratio of power to mass flow rate (energy per mass). This research explores the relationships between plasma reactor parameters such as monomer flow rate, plasma power, and reactor pressure and the rates of polymerization, etching, and deposition. The chemical structure of the amorphous, crosslinked plasma polymerized hexafluoropropylene consists largely of similar amounts of C*-CF, CF, CF₂, and CF₃ groups and some C-C groups. A dimensionless plasma parameter (E) proportional to power and inversely proportional to flow rate cubed was derived. E, reflecting both plasma energy and residence time, was used to describe various aspects of the plasma reactions. A dimensionless exponential expression successfully described the dependence of pressure on E with a master curve. An expression for polymerization efficiency (polymer conversion) derived in part through a mass balance was also successfully related to E using an exponential master curve. The rate of deposition was described as the difference between the rates of polymerization and etching. The deposition efficiency maximum and plateau were successfully described by the difference between polymerization and etching efficiencies, each related exponentially to E. The technique used to derive parameters to describe the dependence of plasma reactions on plasma operating conditions can be applied to any monomer/reactor system.     

Polymerization and chelating behavior of N-acryloyl,N-phenylthiourea

Summary The title monomer has been prepared for the first time. It has been polymerized by a free radical mechanism in different solvents. Only oligomers were obtained so far. The dependence of the rate of polymerization on monomer and initiator concentrations has been measured and was found to follow the usual free radical scheme. The overall activation energy of polymerization has been measured in two solvents and was found to be 21.2 and 15.03 K.Cal/mol in tetrahydrofuran (THF) and N,N-dimethyl formamide (DMF) respectively. The prepared monomer has excellent chelating ability with different metal cations. The stability constant of the monomer with copper (II) ions has been measured in acetone as well as in dioxane. The complexes have no tendency for free radical polymerization.