Kinetics of Free Radical Copolymerization. VII. Kinetic Analysis of Ethyl Acrylate-Styrene Copolymerization in Inert Solvent

The copolymerization kinetics of the ethyl acrylate/styrene/azo-bis-isobutyronitrile/benzene/50°C system was found to deviate from the classical rate equation of copolymerization. The experimental results could not be interpreted by the diffusion theory, the penultimate effect, or the theory of electron donor-acceptor complexes. Our kinetic data were consistently described by the theory of hot radicals, and the 13 parameters characteristic for the copolymerization system were determined from an adequate number of data at different compositions by a nonlinear least-squares method.     

Kinetics of Radical Copolymerization. XII. Investigation of the Rate of Polymerization of the System Styrene-Butyl Acrylate-Benzene

The classical copolymerization rate equation does not describe the copolymerization rate in the styrene-butyl-acrylate-azoiso-butyronitrile-benzene-50°C system appropriately. The cross-termination coefficient (Π), calculated according to the classical rate equation, shows a strong monomer and solvent concentration dependence. The experimental results cannot be interpreted by the diffusion theory, penultimate effect, or the theory of charge transfer complexes. However, Π was found to be constant over the whole concentration range by the hot radical theory. Our kinetic data were consistently described by this theory, and its 13 parameters, characteristic of the copolymerization, were determined.     

D_4/N-β-氨乙基-γ-氨丙基甲基二甲氧基硅烷本体共聚反应聚合度变化的Monte Carlo模拟

用MonteCarlo方法模拟八甲基环四硅氧烷 (D4 )与N β 氨乙基 γ 氨丙基甲基二甲氧基硅烷(APAEDMS)的本体开环共聚动力学 .模拟过程采用自由体积理论简化处理扩散效应并与本征反应动力学耦合 .本征动力学常数通过模拟主要共聚基元反应得到 ,基于优化的动力学常数通过模拟从分子水平揭示D4 APAEDMS本体开环共聚反应过程主要表现为活性阴离子聚合行为 ,同时又伴有部分逐步聚合特征 .     

对O'Driscoll的离子共聚理论的商榷

<正> Mayo和Lewis建立了二元共聚合反应共聚组成方程式,并引出了竞聚率概念。自从Szwmc发现“活性聚合物”以来,人们在研究非极性溶剂中阴离子共聚时,常发现有符合“理想”共聚ν_1·ν_2=1的实验结果,O’2Driscoll和Kuntz用过渡状态理论,提出活性种之间的反应能力差异X倍,用此来调和理论与实验结果的矛盾。本文对O’Driscoll理论进行了修正和完善,并从活性种之间的相互缔合作用对聚合反应的影响     

交替共聚中的自由单体－络合理论

自由基交替共聚理论是共聚合研究中的重要理论问题。本文从交替共聚各种理论中整理出自由单体－络合理论，并从机理、共聚组成和动力学等几方面进行分析和综述，认为该理论能比较全面、真实地反映交替共聚的机理。     

Kinetics of radical copolymerization—VIII Investigation of the effect of molecular inhibitors in copolymerization—1. Bulk copolymerization

The stoichiometry of the inhibition reaction was studied in AN-MA, AN-St and MA-St copolymerization systems in the presence of nitroso-type molecular inhibitors. According to our experiments, the stoichiometric coefficient of the inhibitor depends on the initial composition of monomers. The hot radical theory, elaborated for the inhibition of polymerization, was extended to the inhibited copolymerization; this theory made it possible to explain and to describe quantitatively the variation of experimental μ value with the initial monomer composition.     

Effects of reaction conditions on the structure of graft copolymer

In order to advance the studies of radiation graft copolymerization, we have presented the theory of coupling graft copolymerization and apply it to the investigation of the grafting of methylmethacrylate on to pre-irradiated polystyrene.     

高强度疏水缔合水凝胶的交联网络结构形成机理

高强度疏水缔合水凝胶(HA-gels)是丙烯酰胺(AM)和少量的疏水单体辛基酚聚氧乙烯(4)醚丙烯酸酯(OP-4-AC)在十二烷基硫酸钠(SDS)水溶液中采用胶束共聚的方法制备的.采用胶束共聚理论、橡胶弹性统计理论及Mooney-Rivlin理论,并结合单向拉伸实验数据,对HA-gels的交联网络结构的形成机理进行了探...     

自由基交联共聚合理论模型进展

从模型所使用的数学方法，对自由基交联共聚合理论的模型：概率统计模型、动力学模型和基于逾渗的计算机仿真模型的进展进行了综述。     

A DFT investigation of the mechanism for alternating copolymerization of styrene with carbon monoxide catalyzed by Pd(II) complexes

Density functional theory has been employed to study the homogeneous catalytic copolymerization of styrene with carbon monoxide.The copolymerization reaction is catalyzed by Pd（Ⅱ） coordinated with 2,2’-bipyridine,a conventional nitrogen-containing bidentate ligand with achiral C_2vsymmetry.The chain propagation mechanism for the alternating copolymerization as well as the side reactions,including multiple insertions of CO and homopolymerization of styrene,has been investigated.This study focused exclusively on regioisomerism and stereoisomerism.We have demonstrated that the strictly alternating copolymerization is kinetically and thermodynamically favored over the side reactions（i.e.,multiple insertions of CO and homopolymerization of styrene）.The regiochemistry study indicates the 2,1 type.Furthermore,the stereochemistry study shows that the syndiotactic conformation is preferred over the isotactic or atactic conformations.     

Thermodynamics of homogeneous equilibrium copolymerization from the point of view of the Flory-Huggins theory

A general treatment of the thermodynamics of binary copolymerization from the point of view of the Flory-Huggins theory is given. The relations allow one to determine, on the basis of experimental data, the thermodynamic parameters of copolymerization and the parameters of intercomponent interaction (χ). On the other hand, when these parameters are known, it is possible to predict, for any initial set of conditions, the equilibrium concentrations of comonomers and the equilibrium microstructure of a copolymer. The presented simulations indicate that positive values of interaction parameters increase the volume fractions of copolymer units in equilibrium with comonomers, in comparison to an analogous copolymerization system without intercomponent interactions.     

Graph-theoretic approaches for qualitative analysis and numerical solution of equations of multicomponent copolymerization

An original algorithm for practical realization of the approaches formulated in terms of the graph theory to calculate the dynamics of multicomponent copolymerization has been developed. The employment of such an algorithm provides a possibility to extend the range of copolymerization processes (normally calculated using an ordinary personal computer), bringing the number of the components up to 10, whereas formerly this number did not exceed 5. It has been demonstrated how, upon minor modification, the above algorithm can be employed to find the location of the stationary points of multicomponent copolymerization equations as well as to determine the type of each such a point. © 1996 John Wiley & Sons, Inc.     

Polymerization of vinylcyclopropanes. V. Radical copolymerization of 1, 1-dichloro-2-vinylcyclopropane with monosubstituted ethylenes

A peculiar copolymer composition equation applicable to the radical copolymerization of 1,1-dichloro-2-vinylcyclopropane with monosubstituted ethylenes was developed. The theory was applied to such ethylenes as methyl acrylate, methyl methacrylate, and styrene. The reactivity ratio parameters which give the best fit to the experimental data were determined.     

Influence of the Styrene Ratio on the Copolymerization Kinetics of Dimethacrylate of Diglycidyl Ether of Bisphenol a Vinylester Resins Crosslinked with Styrene

Abstract

Infrared spectroscopy was used in this work to investigate the copolymerization characteristics of systems based on a dimethacrylate of diglycidyl ether of Bisphenol A combined with styrene in variable proportions ranging from 25 to 60% by weight. Particular attention has been paid to determination of the theoretical monomer sequence distributions obtained from copolymerization theory. The results show that the final structure of these materials is probably diphasic, with a first phase consisting of a vinylester network and a second phase rich in polystyrene. The influence of the monomer sequence distribution on the final crosslink density has been evaluated.     

Theoretical consideration of bulk free-radical copolymerization with allowance for the preferential sorption of monomers into globular nanoreactors

The thermodynamics of a globular solution of binary copolymer in two-component solvent is theoretically considered. Classification of phase diagrams of such a solution is performed by their topological appearance. Based on the thermodynamic theory, binary bulk free-radical copolymerization under low conversions is examined in systems where macroradicals being in globular conformational state represent isolated nanoreactors. The theoretical results achieved permit an explanation of all qualitative peculiarities observed experimentally under copolymerization in such anomalous systems.     

Kinetics of copolymerization—VI Investigation of copolymer composition in the system acrylonitrile—methyl acrylate-dimethylformamide

The compositions of copolymers formed under different copolymerization conditions were studied for the system acrylonitrile-methyl acrylate-dimethylformamide at 50°C. The relationship between the compositions of the feed and the copolymer cannot be described with sufficient accuracy either by the classical copolymerization equation or by the equation derived from the penultimate model. The systematic deviations observed on application of the classical composition equation can be qualitatively well interpreted in terms of the hot radical theory.     

Influence of diosgenin structure on the polymerization kinetics of acrylamide: An experimental and theoretical approach

The acrylamide polymerization in presence of diosgenin has been investigated by experimental and theoretical methods. NMR spectroscopy shows the absence of copolymerization. Viscosimetric and dilatometric experiments support the occurrence of transfer reactions that retard the polymerization. The mechanism was studied at the MPWB1K/6-31G(d,p)//B3LYP/6-31G(d,p) level of theory. Transfer, homopropagation, copolymerization and reinitiation reactions were considered either in gas or solution phase. According to results, the retardation seems to be originated by the formation of an allylic radical in the ring B of diosgenin that reinitiates acrylamide polymerization at slow rate.     

偏氯乙烯-氯乙烯悬浮共聚物的结晶与熔融性能

研究了聚合温度、共聚物组成、低分子助剂用量等对偏氯乙烯 (VDC) 氯乙烯 (VC)悬浮共聚树脂的结晶度、熔融峰温度的影响 ,并用Florry的聚合物熔点降低理论预测共聚树脂熔点随共聚组成、低分子助剂用量的变化规律 ,为VDC VC悬浮共聚树脂的合成工艺条件和加工性能的改善提供理论基础 .     

Modeling and semi‐batch control of cross‐link density distribution in the free‐radical copolymerization of vinyl/divinyl monomers

A general model has been developed to describe the cross‐link density development during the free radical copolymerization of vinyl/divinyl monomers. The conventional copolymerization theory based on the terminal model is applied to the cross‐linking system in a novel way. The cross‐link density profile is illustrated for both batch and standard semi‐batch processes. A new semi‐batch feed procedure is proposed that results in a uniform cross‐link density throughout the reaction.     

N-对位取代苯基马来酰亚胺与苯乙烯溶液共聚动力学的研究

以DMF为溶剂 ,采用膨胀计法对N 对位取代苯基马来酰亚胺与苯乙烯的溶液共聚动力学作了系统研究 .其中N 苯基马来酰亚胺与苯乙烯的均相溶液聚合 ,聚合速率方程为Rp=k[I]1/ 2 [M ].同时还测定了四种N 对位取代苯基马来酰亚胺与苯乙烯在DMF中的共聚表观活化能 ,并由此证明四种单体的共聚活性及CTC络合物的存在