Polymerization Mechanisms and Kinetics

R.A. Hutchinson, M.C. Grady and WJ. Simonsick, Preprints International Symposium on Free Radical Polymerization Kinetics and Mechanism, II Ciocco, Italy (2001). 

In order to optimize the structure and properties of composites, a knowledge of the polymerization kinetics and mechanism are required. Various approaches have been taken to a determination of the kinetics of the polymerization including infrared spectroscopy 30,31). Although the various epoxide/anhydride/amine systems are... 

M. Buback and A.M. van Herk. Radical Polymerization Kinetics and Mechanism. Wiley-VCH, Weinheim, 2007. 

Polymerization is influenced by the physical structure and phase of the monomer and polymer. It proceeds in the monomer, and the chemical configuration of the macromolecules formed depends on whether the monomer is a liquid, vapor, or solid at the moment of polymerization. The influence of structural phenomena is evident in the polymerization of acrylic monomer either as liquids or liquid crystals. Supermolecular structures are formed in solid- and liquid-state reactions during and simultaneously with polymerization. Structural effects can be studied by investigating the nucleation effect of the solid phase of the newly formed polymer as a nucleation reaction by itself and as nuclei for a specific supermolecular structure of a polymer. Structural effects are demonstrated also using macromo-lecular initiators which influence the polymerization kinetics and mechanism. 

Polymers are typically complex mixtures in which the composition depends on polymerization kinetics and mechanism and process conditions. To obtain polymeric materials of desired characteristics, polymer processing must be carefully controlled and monitored. Furthermore, one needs to understand the influence of molecular parameters on polymer properties and end-use performance. Molar mass distribution and average chemical composition may no longer provide sufficient information for process and quality control nor define structure-property relationships. Modern characterization methods now require multidimensional analytical approaches rather then average properties of the whole sample [1]. 

Pierik, B. Masclee, D. Vollmerhaus, R. van Herk, A. German, A. L. In Free Radical Polymerization. Kinetics and Mechanism, Macromolecular Symposia Series, Buback, M., Ed. Wiley-VCH Weinheim, 3rd IUPAC-Sponsored International Symposium on Free Radical Polymerization Kinetics And Mechanism, II Chioccho/Lucca, Italy, June 3—8, 2001. 

The mathematical modeling of polymerization reactions can be classified into three levels microscale, mesoscale, and macroscale. In microscale modeling, polymerization kinetics and mechanisms are modeled on a molecular scale. The microscale model is represented by component population balances or rate equations and molecular weight moment equations. In mesoscale modeling, interfacial mass and heat transfer... 

Over 200 references describing spontaneous, and chemically initiated styrene polymerization chemistry are reviewed with special emphasis on advances taking place in the past decade. The review is limited to chemistry useful for making amorphous high molecular weight polystyrene in solution polymerization processes. Chemical initiators have been categorized into three basic groups as follws 1) anionic 2) mono-radical and 3) diradical. Analytical techniques used for determination of free radical polymerization kinetics and mechanisms are also discussed. 

This chapter describes the coordination polymerization of acyclic and cyclic vinylic monomers, conjugated dienes, and polar vinylic monomers with the most important catalytic systems known in this area. A chronological classitication for the development of the main coordination catalyst types is outlined, as well as polymerization kinetics and mechanisms and applications of polymers obtained through different metallic complexes. 

The last part of this chapter deals with coordination polymerization kinetics and mechanism, mathematical models at different scales, as well as some analyses on the supported catalyst particle breakup and growth. 

In some specific cases, analytical solutions for the population balances can also be derived. For instance, Soares and Hamielec [73, 74] obtained analytical dynamic solutions to describe how the CLD of polyolefins varied as a function of time in stopped-flow reactors commonly used for mechanistic studies on olefin polymerization kinetics and mechanism [75-78]. These analytical solutions combine the power of full population balance numerical solutions with the ease and convenience of using closed form equations they are, unfortunately, difficult to attain for more complex cases. 

This volume contains articles of the invited speakers at the lUPAC-sponsored International Symposinm on Radical Polymerization Kinetics and Mechanism held in II Ciocco (Italia) dnring the week September 3-8, 2006. The conference was attended by close to 200 people from all over the world with a good balance between attendees from industry and academia. About 40 per cent of the attendees were Ph.D. students, who very actively participated in the scientific program. 

Strategies for controlling the copolymer composition and MWD of latices based on linear and non-linear copolymers, such as styrene/butyl acrylate copolymers and methyl methacrylate/n-butyl acrylate copolymers, are described. These strategies involve on-line procedures based on calorimetric measurements and open-loop processes employing a mathematical model for determining the trajectories of the manipulated variables, such as monomer feed flow rates and chain transfer agent. 35 refs. (3rd lUPAC-Sponsored International Symposium on Free-Radical Polymerization Kinetics and Mechanism, II Ciocco (Lucca), Tuscany, Italy, 3rd-9th June, 2001)... 

O Driscoll, K. F., and Russo, S., eds. (1996). 2nd International Symposium on Free Radical Polymerization Kinetics and Mechanisms, held in Santa Margherita Figure, Genoa, Italy, 26-31 May 1996, 328 pp. 

A detailed study on the effect of Li Cl on the polymerization kinetics and mechanism is in progress and will be published in more detail elsewhere (32). 

Polymerization Kinetics and Mechanism with Coordination Catalysts 383 8.3... 

Polymerization Kinetics and Mechanism with Coordination Catalysts 389 Tab. 8.1. Terminal model for blna copolymerization of olefins.M... 

Polymerization Kinetics and Mechanism ivith Coordination Catalysts I 395... 

S.3 Polymerization Kinetics and Mechanism with CoonJination Catalysts I 397... 

Frisch, K. Reegen, S. In Ring Opening Polymerizations (Kinetics and Mechanisms ot Polymerization/, Marcel Dekker New York, 1969 Vol. 2, pp 168-169. 

Saverio Russo is a senior professor of industrial chemistry at Genoa University, Italy. He has been, and still is, project leader of several research programs supported by the European Union, Italian Ministry of University, and Chemical Companies. He has been working for more than 40 yeare in the field of macromolecular science and technology, mainly on advanced polymeric materials synthesis, characterization and applications. Polyamide 6 by the anionic routes has been one of the major topics of his research. He is author of more than 250 scientific publications, mostly in international journals, and six patents. Prof Russo has been member of the Scientific Committee of INSTM (Interuniversity Consortium of Materiab Science and Technology) and director of its S Hon on Functional and Structural Polymeric Materials. He was the co- itor of four volumes of Comprehensive Polymer Science, Peigamon, 1989 and two supplement volumes (1992 and 1996). He was the organizer and co-chairman of two lUPAC Symposia of Free Radical Polymerization Kinetics and Mechanism, in 1987 and 1996. 

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