Rates of Polymerization and Depolymerization, Average Molecular Weights, and Molecular Weight Distributions of Polymers

Peebles, L. H.

doi:10.1002/0471532053.bra011

Cited by 5 publications

(4 citation statements)

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“…This scheme effectively suppresses the reactivity of the monomers possessing more active functional groups. Since the Flory-Stockmayer theory has been validated experimentally for systems below the gel point [ 14 , 15 , 16 , 17 , 18 , 19 , 20 ], we conclude that the reaction rates based on Equation ( 18 ) should be used in the MC simulations.…”

Section: Resultsmentioning

confidence: 99%

“…Stockmayer extended the theory to branching units with arbitrary functionalities and derived the Stockmayer formula for the number of polymer chains with a given composition, though ring structures were still excluded [ 11 , 12 , 13 ]. The predictions of the Flory-Stockmayer theory [ 8 , 9 , 10 , 11 , 12 , 13 ], including the gel point and the average molecular weight, have been tested experimentally [ 14 , 15 , 16 , 17 , 18 , 19 , 20 ]. However, the entire MWD is hard to probe experimentally, and often only the average molecular weight is measured.…”

Section: Introductionmentioning

confidence: 99%

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Molecular Weight Distribution of Branched Polymers: Comparison between Monte Carlo Simulation and Flory-Stockmayer Theory

2023

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It is challenging to predict the molecular weight distribution (MWD) for a polymer with a branched architecture, though such information will significantly benefit the design and development of branched polymers with desired properties and functions. A Monte Carlo (MC) simulation method based on the Gillespie algorithm is developed to quickly compute the MWD of branched polymers formed through step-growth polymerization, with a branched polyetherimide from two backbone monomers (4,4′-bisphenol A dianhydride and m-phenylenediamine), a chain terminator (phthalic anhydride), and a branching agent (tris[4-(4-aminophenoxy)phenyl] ethane) as an example. This polymerization involves four reactions that can be all reduced to a condensation reaction between an amine group and a carboxylic anhydride group. A comparison between the MC simulation results and the predictions of the Flory-Stockmayer theory on MWD shows that the rates of the reactions are determined by the concentrations of the functional groups on the monomers involved in each reaction. It further shows that the Flory-Stockmayer theory predicts MWD well for systems below the gel point but starts to fail for systems around or above the gel point. However, for all the systems, the MC method can be used to reliably predict MWD no matter if they are below or above the gel point. Even for a macroscopic system, a converging distribution can be quickly obtained through MC simulations on a system of only a few hundred to a few thousand monomers that have the same molar ratios as in the macroscopic system.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Molecular Weight Distribution of Branched Polymers: Comparison between Monte Carlo Simulation and Flory-Stockmayer Theory

2023

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“…This result is typical for living systems with partial deactivation. 18 The polymer samples used for MWD determination were polymerized at the same temperature; hence, it is not possible to give information about the temperature dependence of the transfer rate.…”

Section: Determination Of Rate Constants and Discussionmentioning

confidence: 99%

Gas‐phase polymerization of butadiene. Data acquisition using minireactor technology and particle modeling

Bartke

Wartmann

Reichert

2002

J of Applied Polymer Sci

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Minireactor technology has been used for kinetic studies on polymerization kinetics, phase equilibrium, and mass transfer on a very small scale. There is a nonlinear influence of temperature and pressure on the polymerization rate. The phase equilibrium can be described by a Flory-Huggins approach, with a temperature-dependent interaction parameter. The diffusion coefficient seems to be slightly pressure dependent, and the temperature dependence can be described with an Arrhenius equation. A simple formal kinetic scheme with formation of active sites, chain propagation, chain transfer to cocatalyst, and deactivation of active sites has been applied. This kinetic scheme was implemented in two different models; they are, a particle model taking into account mass transfer and a simple chemical model with no mass transfer. In principle, both models describe the experimental results for rate and molecular weight distribution equally well, with rate constants of the same magnitude. Molecular weight distributions calculated by the chemical model are narrower. However, the chemical model gives no explanation for the experimental observed rate dependence on catalyst particle size. With increasing catalyst activity, the differences between both models become more significant and the particle model becomes more and more important.

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“…However, almost all these monographs focus on experimental results, whereas burning problems of quantitative theory are rather slightly covered. This deficiency is made up to a certain extent in sections of monographs [11,12] and reviews [13,14]. At the same time, when designing industrial processes, the choice of optimum performance conditions is of critical significance.…”

Section: Introductionmentioning

confidence: 99%

Development of a quantitative theory of polycondensation

Кучанов

2004

Progress in Polymer Science

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Rates of Polymerization and Depolymerization, Average Molecular Weights, and Molecular Weight Distributions of Polymers

Cited by 5 publications

References 331 publications

Molecular Weight Distribution of Branched Polymers: Comparison between Monte Carlo Simulation and Flory-Stockmayer Theory

Molecular Weight Distribution of Branched Polymers: Comparison between Monte Carlo Simulation and Flory-Stockmayer Theory

Gas‐phase polymerization of butadiene. Data acquisition using minireactor technology and particle modeling

Development of a quantitative theory of polycondensation

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