In Situ Time-Dependent Signatures of Light Scattered from Solutions undergoing Polymerization Reactions

Alb, Alina M.; Mignard, Emmanuel; Drenski, Michael F.; Reed, Wayne F.

doi:10.1021/ma035835j

Cited by 20 publications

(12 citation statements)

References 42 publications

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“…polymers in given concentrations and solvents, or pharmaceutical formulations, will now be feasible, whereas use of a traditional, single‐sample light scattering instrument would be totally impractical. In terms of polymerization reactions, it has been demonstrated that SMSLS can (1) determine if a reaction occurs at all, (2) give an indication of the time scale for the reaction to occur if it occurs, (3) give a rough idea of the average polymer mass, and (4) signal any mechanistic hallmarks or peculiarities via the time‐dependent light scattering signature 37…”

Section: Related Complementary Methodsmentioning

confidence: 99%

Automatic continuous online monitoring of polymerization reactions (ACOMP)

Alb

Drenski

Reed

2007

Polymer International

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A brief overview of the principles and associated instrumentation used to monitor polymerization reactions by automatic continuous online monitoring of polymerization reactions (ACOMP) is presented. ACOMP can be used as an analytical method in R&D, as a tool for reaction optimization at the bench and pilot plant level and, eventually, for feedback control of full‐scale reactors. ACOMP measures in a model‐independent fashion the evolution of average molar mass and intrinsic viscosity, monomer conversion kinetics and, in the case of copolymers, also the average composition drift and distribution. A summary of areas of ACOMP application is given, which include free radical and controlled radical homo‐ and copolymerization, polyelectrolyte synthesis, heterogeneous phase reactions, including emulsion polymerization, adaptation to batch and continuous reactors, and modifications of polymers. Finally, a brief sketch of two novel complementary methods is given: automatic continuous mixing (ACM) and simultaneous multiple sample light scattering (SMSLS). Copyright © 2007 Society of Chemical Industry

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Section: Related Complementary Methodsmentioning

confidence: 99%

Automatic continuous online monitoring of polymerization reactions (ACOMP)

Alb

Drenski

Reed

2007

Polymer International

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“…polymer solutions ( = − , as above discussed) allows the estimation of their frozen inhomogeneities [24,39,40]. Important developments concerning the in situ characterization of polymer reactions, namely involving the homopolymerization of acrylamide, were also reported in references [42][43][44]. Indeed, these works showed that time-dependent static light scattering (TDSLS) signatures could be used to describe, experimentally and theoretically, the growing of a polymer population for AAm free radical homopolymerization.…”

Section: In-line Sls Monitoring Of Polymers and Polymer Gel Formationmentioning

confidence: 98%

Static Light Scattering Monitoring and Kinetic Modeling of Polyacrylamide Hydrogel Synthesis

2019

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A kinetic model describing aqueous acrylamide homopolymerization and copolymerization of acrylamide with methylene bisacrylamide, leading to hydrogel formation, is presented and applied in the simulation of these reaction processes. This modeling approach is based on population balances of generating functions and, besides the crosslinking mechanisms inherent to network formation, other specific kinetic steps important in acrylamide polymerization (e.g., branching due to backbiting) are considered in the simulation tool developed. The synthesis of acrylamide polymers and hydrogels was performed at 26 °C and at 40 °C using two different initiation systems. The formation of such materials was monitored using in-line static light scattering (SLS), and the spatial inhomogeneity of the final hydrogels was also measured using this experimental technique. It is shown that the simulations are helpful in describing information provided by SLS in-line monitoring, namely in the early stages of polymerization with the transition from dilute to semi-dilute regime. Indeed, it finds a plausible match between the critical overlap polymer concentration and gelation, this later leading to the observed spatial heterogeneity of the hydrogels. Usefulness of the kinetic model for defining operation conditions (initial composition, semi-batch feed policies, chain transfer, etc.) in making the shift from gelation to the semi-dilute regime is discussed, and the extension of this approach to processes enabling a higher control of gelation (e.g., controlled radical polymerization) is also prospected.

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“…The 1.23 exponent is the reciprocal of the [h] w $ M 0.81 found previously. [40] Direct Monitoring of the Cross-Over from Diffusion-Controlled to . .…”

Section: Analysis Of Trends In M W and [H] Wmentioning

confidence: 99%

Direct Monitoring of the Cross‐Over from Diffusion‐Controlled to Decomposition‐Controlled Initiation in Free Radical Polymerization

Kreft¹,

Reed²

2008

Macro Chemistry & Physics

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High‐resolution free radical polymerization kinetics was obtained using automatic continuous online monitoring of polymerization reactions (ACOMP). A sharp cross‐over from diffusion‐controlled initiation at low [monomer] to initiator decomposition control at higher [monomer] was found, and agrees with the quasi‐steady state approximation (QSSA). The cross‐over was also measurable within individual experiments. The kinetic implications for polymer weight average molecular weight $\overline M _{\rm w}$ and intrinsic viscosity (η)w were analyzed, and the QSSA‐predicted trends for the ratios of final to initial $\overline M _{\rm w}$, and (η)w, confirmed. Analytical expressions for conversion are contrasted, and it was found that first‐order fits, while not fully justified theoretically, nonetheless are robust, which simplifies calculations needed for controlling molecular weight distributions in “semi‐batch” reactions, where reagents are fed to the reactor through programmable flow profiles. At the low monomer concentrations used, there was no evidence that propagation or termination rate coefficients changed during the reactions.magnified image

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In Situ Time-Dependent Signatures of Light Scattered from Solutions undergoing Polymerization Reactions

Cited by 20 publications

References 42 publications

Automatic continuous online monitoring of polymerization reactions (ACOMP)

Automatic continuous online monitoring of polymerization reactions (ACOMP)

Static Light Scattering Monitoring and Kinetic Modeling of Polyacrylamide Hydrogel Synthesis

Direct Monitoring of the Cross‐Over from Diffusion‐Controlled to Decomposition‐Controlled Initiation in Free Radical Polymerization

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