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Journal ArticleDOI

A Simple Dilatometric Method of Determining the Rate Constants of Chain Reactions. II. The Effect of Viscosity on the Rate Constants of Polymerization Reactions1

01 Mar 1959-Journal of the American Chemical Society (American Chemical Society)-Vol. 81, Iss: 6, pp 1339-1345
About: This article is published in Journal of the American Chemical Society.The article was published on 1959-03-01. It has received 99 citations till now. The article focuses on the topics: Viscosity & Polymerization.
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Book ChapterDOI
TL;DR: In this paper, the formation of densely crosslinked networks by chain crosslinking photopolymerization is discussed in relation to selected applications in the electronics industry, which make use of the high speed and the latitude to meet other requirements by variation of the chemical structure of the monomers.
Abstract: The formation of densely crosslinked networks by chain crosslinking photopolymerization is discussed in relation to selected applications in the electronics industry. All of these applications make use of the high speed and of the latitude to meet other requirements by variation of the chemical structure of the monomers. The selection comprises: 1. The coating of optical fibers; 2. The replication of optical discs; 3. The replication of aspherical lenses, used for laser read-out of these discs.

406 citations

Journal ArticleDOI
TL;DR: A plethora of models have been developed quantifying the effect of diffusion-controlled phenomena on polymerization reactions as mentioned in this paper, including innovative ones that have emerged over the last decade, including innovative models that have been used in free-radical and step-growth polymerization.
Abstract: A plethora of models have been developed quantifying the effect of diffusion-controlled phenomena on polymerization reactions. The most prominent approaches are reviewed here, including innovative ones that have emerged over the last decade. Free-radical and step-growth polymerizations are considered in a way to show that similar models have been used in both mechanisms. In free-radical polymerization the models proposed are subdivided according to their theoretical background into four categories: (i) based on a Fickian description of reactant diffusion; (ii) free-volume theory based; (iii) chain-length dependent; and, (iv) empirical. The reversible addition-fragmentation technique is discussed, together with two industrially important case-studies, solid state polycondensation and epoxy-amine curing.

209 citations

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the effect of polymer matrix architecture on the termination of linear polyMA radicals and compared this to polystyrene, polymethyl methacrylate, and polyvinyl acetate systems.
Abstract: The reversible addition-fragmentation chain transfer-chain length dependent termination (RAFT-CLD-T) method has allowed us to answer a number of fundamental questions regarding the mechanism of diffusion-controlled bimolecular termination in free-radical polymerization (FRP). We carried out RAFT-mediated polymerizations of methyl acrylate (MA) in the presence of a star matrix to develop an understanding of the effect of polymer matrix architecture on the termination of linear polyMA radicals and compared this to polystyrene, polymethyl methacrylate, and polyvinyl acetate systems. It was found that the matrix architecture had little or no influence on termination in the dilute regime. However, due to the smaller hydrodynamic volumes of the stars in solution compared to linear polymer of the same molecular weight, the gel onset point occurred at greater conversions, and supported the postulate that chain overlap (or c*) is the main cause for the observed autoacceleration observed in FRP. Other theories based on short-long termination or free-volume should be disregarded. Additionally, since our systems are well below the entanglement molecular weight, entanglements should also be disregarded as the cause of the gel onset. The semidilute regime occurs over a small conversion range and is difficult to quantify. However, we obtain accurate dependencies for termination in the concentrated regime, and observed that the star polymers (through the tethering of the arms) provided constriction points in the matrix that significantly slow the diffusion of linear polymeric radicals. Although, this could at first sight be postulated to be due to reptation, the dependencies showed that reptation could be considered only at very high conversions (close to the glass transition regime). In general, we find from our data that the polymer matrix is much more mobile than what is expected if reptation were to dominate. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3155-3173, 2008

128 citations

Journal ArticleDOI
TL;DR: A review of the most prominent approaches for measuring termination rate coefficients of free-radical polymerization (FRP) is presented in this article, including innovative ones that have emerged over the last decade and can be divided into two categories: (i) kinetic methods, in which analysis of the time dependence of concentrations is essential, and (ii) molecular weight distribution plays the dominant role.

125 citations

Journal ArticleDOI
TL;DR: In this article, the process of bimolecular reaction between A and B is given by Eq. (1), taking into account the diffusion step bringing the two reactions in proximity.
Abstract: Chemical reactions require that at least two molecules or reacting groups come into close proximity so that energy, electrical charge, or chemical groups may be exchanged between them. The process of bimolecular reaction between A and B is given by Eq. (1), taking into account the diffusion step bringing the two reactions in proximity, (AB)

118 citations