Design of 2‐hydroxyethyl methacrylate‐functional macromonomer dispersants by semi‐batch cobalt chain transfer polymerization

Steenberge, Paul H. M. Van; Hutchinson, Robin A.

doi:10.1002/aic.16723

Cited by 24 publications

(35 citation statements)

References 40 publications

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“…Here we refer to the special case of oligomerization, e.g., the radical poly merization of vinyl monomers in the presence of highly efficient chain transfer agents such as cobalt complexes. [137][138][139] Under such conditions, high chain transfer rates are established compared to the conventional case in which the formation of longer chains is much more facilitated. Conventionally with chain transfer still as dominant chain stopping mechanism instantaneous dispersity values of 2 are obtained, as following from the SF distribution evaluated considering the long-chain limit approximation.…”

Section: Guidelines For Implementation Of Chain Length and Molar Mass Distributions In Kinetic Modeling Studiesmentioning

confidence: 99%

Translating Simulated Chain Length and Molar Mass Distributions in Chain‐Growth Polymerization for Experimental Comparison and Mechanistic Insight

Marien

Edeleva

Figueira

et al. 2021

Macro Theory & Simulations

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From an industrial point of view, it has often been claimed that MMDs need to possess a sufficiently large mass average molar mass M m (e.g., 10 6 g mol −1 ) to ensure sufficient entanglements and must be broad, requiring dispersity (Ð) values well above 1.5. [5,8] For specific applications, such as coatings, MMD bimodality has even been put forward as the primary target, leading to dispersity values higher than 4. [15][16][17] For the determination of the radical propagation, [18][19][20][21][22][23] backbiting, [24][25][26][27] and β-scission [24,28] rate coefficients or the quantification of photo dissociation quantum yields, [29] a modulated MMD trace is beneficial. In contrast to modulated and broad MMDs, the more recent chemical development of living and reversible deactivation radical poly merization (L/RDRP) mechanisms has made clear that more niche applications (e.g., drug delivery or high-end cosmetics) can benefit from lower M m values (e.g., 10 4 g mol −1 ) and narrow monomodal MMDs with Ð values below 1.5. [30][31][32][33][34][35][36] This dedicated molecular tailoring is also related to control over end-group functionality to enable the synthesis of more special polymers such as block, gradient, and star (co)polymers. [37][38][39][40][41] Therefore, a dedicated knowledge of the relationship between reaction conditions and MMD is indispensable for any polymerization mechanism.The key analytical tool for MMD characterization is size exclusion chromatography (SEC) or equivalently gel permeation chromatography (GPC) in which longer chains-so species with higher molar masses-elute first, as they have fewer interactions with the smaller pores in the packed columns. The chains with the highest molar masses are thus located at the lowest retention times (RTs) in the chromatogram so that the recorded chromatogram corresponds to a "reverse" MMD. This is illustrated in Figure 1a employing a refractive index (RI) detector, which is also known as single GPC detection. Ideally, calibration takes place with standards of the same polymer type that are characterized by very narrow MMDs (Ð values close to 1), as demonstrated in Figure 1b. In many research groups, one finally aims at a log-MMD representation, requiring a normalization on logarithmic scale. This is illustrated by the arrow between Figure 1c,d and leadsThe molar mass distribution (MMD), which is also known as the molecular weight distribution (MWD), is a key molecular property for a polymerization process, as it determines polymer strength and polymeric material deformation. Several MMD and related chain length distribution (CLD) representations are however used interchangeably, often leading to biased conclusions. Herein it is highlighted how the most interesting simulated CLD/MMD representations, i.e., the number, mass, z-based, and logarithmic CLD/MMD, can be translated into each other and how they need to be corrected to facilitate comparison with experimental size exclusion chromatography traces. Their relevance is highlighted by including case st...

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Section: Guidelines For Implementation Of Chain Length and Molar Mass Distributions In Kinetic Modeling Studiesmentioning

confidence: 99%

Translating Simulated Chain Length and Molar Mass Distributions in Chain‐Growth Polymerization for Experimental Comparison and Mechanistic Insight

Marien

Edeleva

Figueira

et al. 2021

Macro Theory & Simulations

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“…Hence, the kinetics of FRP need to be described with apparent termination rate coefficients, instead of intrinsic ones, i.e., a gel-effect needs to be accounted for as evidenced by an increase in polymerization rate and average chain length compared to the situation of (theoretical) intrinsic kinetics [62]. Chain length dependencies also exist for other reactions, but are typically intrinsic and often limited to the lower chain lengths, as is the case for propagation and chain transfer reactions [63,64]. At higher monomer conversions one should account for a potential cage and glass effect which, respectively, correspond to diffusional limitations on radical initiator dissociation and propagation [65].…”

Section: Radical Polymerization Mechanismmentioning

confidence: 99%

Progress in Reaction Mechanisms and Reactor Technologies for Thermochemical Recycling of Poly(methyl methacrylate)

et al. 2020

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Chemical or feedstock recycling of poly(methyl methacrylate) (PMMA) by thermal degradation is an important societal challenge to enable polymer circularity. The annual PMMA world production capacity is over 2.4 × 106 tons, but currently only 3.0 × 104 tons are collected and recycled in Europe each year. Despite the rather simple chemical structure of MMA, a debate still exists on the possible PMMA degradation mechanisms and only basic batch and continuous reactor technologies have been developed, without significant knowledge of the decomposition chemistry or the multiphase nature of the reaction mixture. It is demonstrated in this review that it is essential to link PMMA thermochemical recycling with the PMMA synthesis as certain structural defects from the synthesis step are affecting the nature and relevance of the subsequent degradation reaction mechanisms. Here, random fission plays a key role, specifically for PMMA made by anionic polymerization. It is further highlighted that kinetic modeling tools are useful to further unravel the dominant PMMA degradation mechanisms. A novel distinction is made between global conversion or average chain length models, on the one hand, and elementary reaction step-based models on the other hand. It is put forward that only by the dedicated development of the latter models, the temporal evolution of degradation product spectra under specific chemical recycling conditions will become possible, making reactor design no longer an art but a science.

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“…The validity of the approach is demonstrated by agreement between the stochastic model applied to acrylate homopolymerization with the Predici implementation, as demonstrated in Figure S1, Supporting Information. Note that the application of stochastic modeling techniques, particularly for BA polymerization, is also well established by other research groups; [4,14,[28][29][30][31][32][33][34][35] herein, we focus on the application of the model to better understand polymer synthesis under semi-batch reaction conditions.…”

Section: + → +mentioning

confidence: 99%

“…Designing polymeric material for targeted applications requires an understanding of how operating conditions influence molecular structure. [3][4][5][6][7][8] Starved-feed freeradical solution semi-batch polymerization of acrylates at high temperatures is an industrially viable process for producing low molecular weight acrylic binder resins used in adhesives and automotive coatings due to the versatile functionality the acrylate family imparts for control of chemical and mechanical properties. [9,10] The polymerization rate and polymer properties are greatly influenced by a series of secondary reactions triggered by intramolecular chain transfer to polymer (known as backbiting) that forms reactive midchain radicals (MCRs), establishing branchpoints through monomer addition or reactive terminal double-bond chain ends via chain scission.…”

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confidence: 99%

Stochastic Modeling of Poly(acrylate) Distributions Obtained by Radical Polymerization under High‐Temperature Semi‐Batch Starved‐Feed Conditions: Investigation of Model Predictions versus Experimental Data

Nasresfahani

Heidarzadeh

Bygott

et al. 2021

Macro Theory & Simulations

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Secondary reactions significantly affect acrylate polymerization rates as well as the architecture of polymer produced by high‐temperature solution radical polymerization. This impact is amplified under the semi‐batch starved‐feed policy used to keep monomer concentration low. Thus, the importance of intramolecular chain transfer (backbiting) is significantly increased, generating a tertiary radical center capable of termination, propagation, and scission. In this investigation, a comprehensive stochastic model is formulated to represent results from an experimental study designed to increase the fraction of reactive terminal double bonds (TDB) in the poly(butyl acrylate) product. Model predictions generated using three sets of literature kinetic parameters for backbiting and scission are compared. While each provides reasonable predictions of some reaction characteristics (e.g., free monomer levels, polymer molecular weights, polymer TDB content), none provide an adequate representation of all aspects of the polymerization. It is concluded that other reaction pathways might be needed to represent the system under semi‐batch conditions, thus explaining the discrepancies seen among the current parameter estimates.

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Design of 2‐hydroxyethyl methacrylate‐functional macromonomer dispersants by semi‐batch cobalt chain transfer polymerization

Cited by 24 publications

References 40 publications

Translating Simulated Chain Length and Molar Mass Distributions in Chain‐Growth Polymerization for Experimental Comparison and Mechanistic Insight

Translating Simulated Chain Length and Molar Mass Distributions in Chain‐Growth Polymerization for Experimental Comparison and Mechanistic Insight

Progress in Reaction Mechanisms and Reactor Technologies for Thermochemical Recycling of Poly(methyl methacrylate)

Stochastic Modeling of Poly(acrylate) Distributions Obtained by Radical Polymerization under High‐Temperature Semi‐Batch Starved‐Feed Conditions: Investigation of Model Predictions versus Experimental Data

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