1 edition of Chain-length dependent bimolecular termination in free-radical polymerization found in the catalog.
Chain-length dependent bimolecular termination in free-radical polymerization
John Bernhard Lidwien de Kock
Diss., Techn. University Eindhoven, 1999.
|Statement||door John Bernhard Lidwien de Kock|
|The Physical Object|
|Pagination||208 S :|
|Number of Pages||208|
Another important parameter related to polymerization rate is the average kinetic chain length, \(\overline because of the presence of bimolecular termination. The living radical polymerization can be achieved by minimizing normal bimolecular termination and prolonging the lifetime of living polymers. All are formed in free radical. Methods for controlling free-radical polymerization have from bimolecular termination reactionsthroughtheir reversible storage as dormant thiocarbonyl compounds (see Scheme 1). into account the chain-length dependence of the addition–.
Termination can occur by combination, by disproportionation or by chain transfer reactions. Termination by combination occurs when two propagating radical chains of arbitrary degrees of polymerization meet at their free-radical ends. Termination by disproportionation gives two terminated chains. Barner-Kowollik, Christopher & Russell, Gregory () Chain-length-dependent termination in radical polymerization: Subtle revolution in tackling a long-standing challenge. Progress in Polymer Science, 34(11), pp.
Chain-length dependent bimolecular termination in free-radical polymerization: theory, validation and experimental application of novel model-independent methods Author Kock, . kinetics assumes chain length independent bimolecular termination and pseudo-steady state radical concentrations, predicting that the polymerization rate (R p) depends on the initiation rate (R i) to the 1/2 power (Eq. (1), where a is the scaling exponent that describes this relationship) [48,49]. R p Z k p ﬃﬃﬃﬃﬃﬃ 2k t p ½CZC Ra i.
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A mathematical model of multivinyl monomer free radical photopolymerizations that takes into account chain length dependent termination (CLDT) and gel formation (an infinite network) was utilized to obtain a more accurate picture of network formation and multivinyl monomer photopolymerization by: The kinetics of chain-length-dependent bimolecular terminations in free-radical polymerization during unstationary state periods are investigated by employing Monte Carlo simulations in segregated microreactors where pseudobulk kinetics is by: 8.
Dependence of 〈k p 〉/〈k t 〉 1/2 on the mol fraction of DDM, f DDM, in the bulk free-radical polymerization of MMA at 60 °C. o: experimental values obtained from the data in Table 1, using fk d = ×10 −6 s −1.
—: simulation results considering only chain length dependent termination (Model I). - - -: simulation results Cited by: The chain-length dependence of the termination rate coefficient, kt, in butyl acrylate free-radical polymerization has been determined by two independent methods, RAFT-SP-PLP and RAFT-CLD-T, both employing control of radical chain length by reversible addition fragmentation chain transfer (RAFT) by: The chain length dependence of bimolecular termination in the solution polymerization of styrene was examined at 25 °C with the solvents (50% per.
After a period of quiet following O’Driscoll's review on “The kinetics of bimolecular termination” and a Russian review on “Role of diffusion-controlled reactions in free-radical polymerization”, there have admittedly been recent reviews on “Bimolecular termination at low conversion”, on “The kinetics of free-radical.
A new method for analyzing the chain length dependence of termination rate coefficients (kt(i,j) where i and j are the chain lengths of the reacting radicals) in low conversion free radical polymerizations is described. The method involves comparing experimental molecular weight distributions of polymers formed in pulsed laser photolysis experiments with those predicted by.
Macromolecules All Publications/Website. OR SEARCH CITATIONS. For high accuracy and reliability of the kinetic results, pulsed-laser techniques were developed to study chain-length-dependent termination [,, ].
In single-pulse pulsed-laser polymerization, ESR provides direct evidence of bimolecular termination. The bimolecular termination is a diffusion-controlled process from the beginning of the polymerization.
the termination rate coefficient is a chain-length-dependent process since length of the macroradicals changes during the reaction that results in differences in their mobility.
relative to free-radical polymerization. The pseudo-kinetic rate constant method in which the kinetic treatment of a multicomponent polymerization reduces to that of a homopolymerization is a. The (mean) rate coefficient of bimolecular chain termination k̄t for bulk polymerization of styrene was determined as a function of chain length and temperature by three different methods.
The unanim. 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).
Molecular Weight Distribution in Free-Radical Polymerization with Chain-Length-Dependent Bimolecular Termination. Bulk Polymerization Tobita, Hidetaka; Abstract. Publication: Macromolecules. Pub Date: July DOI: /maa Bibcode: MaMolT.
Chain-length dependent termination and catalytic inhibition 22 Cobalt – carbon bond formation 32 Catalyst deactivation 34 Reactivity and application of macromonomers 35 References 37 3 Mechanistic aspects of low conversion catalytic chain transfer 41 polymerization of methacrylates.
The effect of chain‐length dependent propagation at short chain lengths on the observed kinetics in low‐conversion free‐radical polymerization (frp) is investigated. It is shown that although the val. Molecular Weight Distribution in Free-Radical Polymerization with Chain-Length-Dependent Bimolecular Termination.
Emulsion Polymerization Tobita, Hidetaka; Abstract. Publication: Macromolecules. Pub Date: July DOI: /maa Bibcode: MaMolT. [6, 24,Some of the earliest styrene free-radical modelling work was done by Hamielec et al.  They studied the AIBNinitiated free radical polymerization of.
The kinetics of chain-length-dependent bimolecular terminations in free-radical polymerization during unstationary state periods are investigated by employing Monte Carlo simulations in segregated.
Free-radical polymerization (FRP) is a method of polymerization by which a polymer forms by the successive addition of free-radical building blocks.
Free radicals can be formed by a number of different mechanisms, usually involving separate initiator molecules. Following its generation, the initiating free radical adds (nonradical) monomer units, thereby growing the polymer chain. This theory of polymerization kinetics uses the concepts of free volume and chain entanglements to describe the relationship between chain mobility and chain length dependent termination .Mohammad Najafi, Hossein Roghani-Mamaqani, Mehdi Salami-Kalajahi, Vahid Haddadi-Asl, An exhaustive study of chain-length-dependent and diffusion-controlled free radical and atom-transfer radical polymerization of styrene, Journal of Polymer Research, /s, 18, 6, (), ().In order to assess the general consequences of an eventual chain length dependence of the bimolecular termination rate constant kt in free radical polymerization, an iterative procedure for.