Detailed modelling of MMA dispersion polymerization in supercritical carbon dioxide

Mueller, Philipp A.; Storti, Giuseppe; Morbidelli, Massimo

doi:10.1016/j.ces.2004.11.029

Cited by 58 publications

(76 citation statements)

References 42 publications

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“…The model used for the quantitative comparison with the experimental data discussed in the following has originally been developed by Mueller et al [1,25] It is a comprehensive, generalized kinetic model of heterogeneous polymerization in scCO 2 , Table 1. Recipes and conditions.…”

Section: Polymerization Modelmentioning

confidence: 99%

“…[23] In a previous contribution [24] we showed that the latter model is unlikely to be applicable for the polymerization system under consideration when using reasonable parameter values and thus prompting us to develop a new model accounting for the detailed description of the radical interphase transport. [25] The so-called V-analysis introduced in the same work was focused on the comparison of the characteristic times of termination and interphase mass transport. This analysis showed that in the case of MMA dispersion polymerization in scCO 2 a situation of irreversible transport from the continuous phase to the polymer particles prevails.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Dispersion Polymerization of Methyl Methacrylate in Supercritical Carbon Dioxide: Control of Molecular Weight Distribution by Adjusting Particle Surface Area

Mueller

Storti

Morbidelli

et al. 2007

Macromolecular Symposia

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Summary: Experiments of methyl methacrylate dispersion polymerization are carried out in a reaction calorimeter using PDMS-mMA as surfactant. Different stabilizer concentrations from 0 to 10 wt% with respect to monomer have been considered in order to control particle morphology. The analysis by scanning electron microscopy reveals a definite decrease of the total particle surface area at decreasing stabilizer concentration. At the same time, the analysis of the polymer microstructure by gel permeation chromatography shows a trend of the average molecular weight towards smaller values. In particular, a second mode at low molecular weights has been observed leading to bimodal molecular weight distributions. The experimental results are compared with simulation results obtained through a detailed kinetic model developed in previous studies.[1] The key role of the radical exchange between continuous and dispersed phases is confirmed.

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Section: Polymerization Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dispersion Polymerization of Methyl Methacrylate in Supercritical Carbon Dioxide: Control of Molecular Weight Distribution by Adjusting Particle Surface Area

Mueller

Storti

Morbidelli

et al. 2007

Macromolecular Symposia

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“…In general, the relative relevance of such loci is of primary importance in determining the polymer MWD. [12,13] In the specific case under examination, the situation is different; both the monomers (MG3, MG4, and MG5) and their polymers (PG3, PG4, and PG5) were found to be practically insoluble in scCO 2 , which will lead to a continuous phase made of CO 2 only and a polymer-rich phase which contains the entire mass of both monomer and polymer. It was therefore, an important first step to see whether scCO 2 is soluble in the second phase at all.…”

Section: Resultsmentioning

confidence: 98%

Dendronized Polymers via Macromonomer Route in Supercritical Carbon Dioxide

Costa

Kasëmi

Storti

et al. 2008

Macromol. Rapid Commun.

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Radical polymerizations from third to fifth generation macromonomers were conducted in supercritical carbon dioxide (scCO2). It was found that all monomers were not soluble in such a medium, and reactions occurred in the CO2‐swollen monomer matrices. Despite the expected severe diffusion limitations, very high conversions and molecular weights were obtained. It is believed that the plasticization effect induced by the CO2 plays a key role in these surprising findings. Scanning force microscopical analyses confirmed that mainly linear dendronized polymers were obtained and therefore chain transfer to polymer is virtually irrelevant.magnified image

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“…[30] Comprehensive models allow computation of the full molar mass distribution (for linear cases) by using phase equilibrium, a kinetic description of the reaction and mass transport calculations. [31][32][33][34] On the other hand, simplified models, such as the method of moments, and simple equilibrium calculations have been also used to describe the behavior of these simpler systems. [35][36][37] To the best of our knowledge, the modeling of copolymerization kinetics, molar mass development, and gel fraction evolution for vinyl/divinyl monomers in the presence of RDRP controllers, in scCO 2 , has not been addressed or has been addressed assuming a single phase situation.…”

Section: Doi: 101002/mats201700064mentioning

confidence: 99%

Modeling of RAFT Copolymerization with Crosslinking of Styrene/Divinylbenzene in Supercritical Carbon Dioxide

López‐Domínguez

Hernández‐Ortiz

Vivaldo‐Lima

2017

Macro Theory & Simulations

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medium for radical polymerizations since it is nontoxic and has a readily accessible critical point, T c = 31 °C and P c = 74 bar (mild conditions compared to water whose critical conditions are T c = 374 °C and P c = 221 bar). [19] Furthermore, side reactions in CO 2 , such as chain transfer to solvent and formation of complexes with monomer and polymer, are not expected. [20] Reversible deactivation radical homoand copolymerizations in scCO 2 have been reported for RAFT, [21][22][23][24][25][26] ATRP, [27] and NMRP. [28,29] In these reports the polymerizations have been claimed to proceed in a controlled manner with low molar mass dispersities (Ð < 1.5). Modeling of (co)polymerization kinetics and molar mass development in scCO 2 for linear systems or conventional (uncontrolled) nonlinear ones has already been addressed in the literature. Since the polymer is often insoluble in scCO 2 , the polymerization proceeds in dispersion or precipitation in two reaction sites, the CO 2 -rich and the polymer-rich phases. [30] Comprehensive models allow computation of the full molar mass distribution (for linear cases) by using phase equilibrium, a kinetic description of the reaction and mass transport calculations. [31][32][33][34] On the other hand, simplified models, such as the method of moments, and simple equilibrium calculations have been also used to describe the behavior of these simpler systems. [35][36][37] To the best of our knowledge, the modeling of copolymerization kinetics, molar mass development, and gel fraction evolution for vinyl/divinyl monomers in the presence of RDRP controllers, in scCO 2 , has not been addressed or has been addressed assuming a single phase situation. [38] In this contribution, we use a multifunctional polymer molecule approach developed in our group, [39] along with a simple partition of the main components in the scCO 2 -rich and polymer-rich phases, to model the RAFT copolymerization with crosslinking of vinyl/divinyl monomers in scCO 2 . The resulting model represents a RAFT dispersion copolymerization (with crosslinking) process and it could very well describe a process where scCO 2 is replaced by water or any other appropriate solvent as the continuous phase. The model is validated by comparing calculated and experimental profiles of conversion versus time, number and weight average molar masses versus conversion, gel fraction and swelling index versus conversion and copolymer composition versus conversion for the RAFT copolymerization of styrene and divinylbenzene in scCO 2 . The experimental data used for model validation purposes was generated in our laboratory. [23] RAFT Copolymerization A kinetic model for the reversible addition-fragmentation chain transfer radical copolymerization of vinyl/divinyl monomers in supercritical carbon dioxide, using a multifunctional approach for polymer network formation, is presented. The process is assumed to proceed as a dispersion polymerization in three stages, with two phases: CO 2 -and polymer-rich phases. A simple model for partit...

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Detailed modelling of MMA dispersion polymerization in supercritical carbon dioxide

Cited by 58 publications

References 42 publications

Dispersion Polymerization of Methyl Methacrylate in Supercritical Carbon Dioxide: Control of Molecular Weight Distribution by Adjusting Particle Surface Area

Dispersion Polymerization of Methyl Methacrylate in Supercritical Carbon Dioxide: Control of Molecular Weight Distribution by Adjusting Particle Surface Area

Dendronized Polymers via Macromonomer Route in Supercritical Carbon Dioxide

Modeling of RAFT Copolymerization with Crosslinking of Styrene/Divinylbenzene in Supercritical Carbon Dioxide

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