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

López‐Domínguez, Porfirio; Hernández‐Ortiz, Julio C.; Vivaldo‐Lima, Eduardo

doi:10.1002/mats.201700064

Cited by 19 publications

(13 citation statements)

References 53 publications

(69 reference statements)

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“…Dispersion polymerization begins as a single phase until polymer molecules reach a critical size and phase separate thus forming a second polymer‐rich phase. Dispersion polymerization has been modeled assuming that it proceeds in three stages where simple semiempirical equations are used for the partition of the main components in the reaction volume . The partition of monomer and solvent has been implemented according to the following equations …”

Section: Modelingmentioning

confidence: 99%

“…In order to account for diffusion‐controlled effects, all reactions were modified following Equation , where k i is effective kinetic rate constant, and

k_{i}^{0}

is the corresponding intrinsic kinetic rate constant, V f0 is fractional free volume at initial conditions; V f is fractional free volume at time t ; and β i is a free volume parameter. Fractional free volume was calculated using Equation , where α n , T g n , and ϕ n are the expansion coefficient, glass transition temperature, and volume fraction for component n , respectively

k_{i} = k_{i}^{0} \exp ([], - β_{i} (\frac{1}{V_{normalf}} - \frac{1}{V_{f 0}}))

V_{normalf} = 0.025 + \sum_{n = 1}^{# normalof normalcomponents} α_{n} (T - T_{normalg n}) φ_{n}

…”

Section: Modelingmentioning

confidence: 99%

“…The transport of low‐molar‐mass species was modeled by using the “phase‐exchange” step while migration of radicals was addressed with the “ k (s)‐termination” step. Simpler expressions for partition of components have also been implemented in conventional free radical homopolymerizations and copolymerization with crosslinking obtaining reasonable predictions of the average polymer properties.…”

Section: Introductionmentioning

confidence: 99%

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A Modeling Study on the RAFT Polymerization of Vinyl Monomers in Supercritical Carbon Dioxide

López‐Domínguez

Jaramillo‐Soto

Vivaldo‐Lima

2018

Macro Reaction Engineering

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synthesized by RAFT copolymerization in scCO 2 . [12] Homopolymerizations of methyl methacrylate (MMA), [13][14][15] styrene, [16] and methyl acrylate (MA) [17] have also been reported. Molar masses were linear with conversion; however, molar mass dispersity (Đ) values greater than 1.5 were experimentally measured in some cases, which is unexpected for controlled cases.Most polymerizations carried out in scCO 2 occur as heterogeneous processes. Since long-chain polymer molecules are insoluble in scCO 2 , two distinct phases are present, a CO 2 -rich phase (continuous) and a polymer-rich phase (dispersed). [9,18] In order to study the development of polymer properties, the kinetics of both phases should be considered. Mass transfer of low-and high-molar-mass species between the continuous and dispersed phases takes place during the polymerization. If the rate of mass transfer of the low-molar-mass species is sufficiently fast, such that their concentrations in both phases are close to their equilibrium values, thermodynamic models can be used to estimate their current values. Two-phase equilibrium problems involving polymer/solvent interactions have been addressed with several approaches: i) equations of state, ii) perturbation models, and iii) lattice-fluid models. [19] Oligomeric radicals produced in the continuous phase are either assumed to remain in that phase or migrate to the dispersed phase once they reach a critical chain length, P nc . [18,20,21] Some reports have focused on the influence of monomer-toinitiator ratio, initial monomer loading and pressure on P nc . [22] The modeling of RAFT polymerization has been performed via deterministic methods, [23][24][25] implementation of polymerization schemes within the commercial software Predici, [26][27][28] and stochastic methods. [29][30][31] It requires knowledge of the activity of the RAFT agent as well as appropriate models for diffusioncontrolled effects; however, there is no universal methodology to accurately determine the apparent addition and fragmentation kinetic rate constants. [32,33] Likewise, the so-called "slow fragmentation" and "intermediate radical termination" approaches have been proposed in order to describe experimental observations. [34] Predici has been used to describe the RAFT polymerization of MMA with 2,2′-Azobis(2-methylpropionitrile) (AIBN) as the initiator and S-thiobenzoyl thioglycolic acid (TBTGA) as the RAFT agent in scCO2. [27] The transport of low-molar-mass species was modeled by using the "phase-exchange" step while migration of radicals was addressed with the "k(s)-termination" step. Simpler expressions for partition of components have also RAFT Polymerization The kinetic modeling of reversible addition-fragmentation chain transfer (RAFT) dispersion homopolymerization of vinyl monomers in supercritical carbon dioxide is addressed. The model accounts for two reaction loci, a polymerrich phase (dispersed) and a solvent-rich phase (continuous). In one of the models, the partition of low molar mass components is estimated ...

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Section: Modelingmentioning

confidence: 99%

“…In order to account for diffusion‐controlled effects, all reactions were modified following Equation , where k i is effective kinetic rate constant, and

k_{i}^{0}

k_{i} = k_{i}^{0} \exp ([], - β_{i} (\frac{1}{V_{normalf}} - \frac{1}{V_{f 0}}))

V_{normalf} = 0.025 + \sum_{n = 1}^{# normalof normalcomponents} α_{n} (T - T_{normalg n}) φ_{n}

…”

Section: Modelingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Modeling Study on the RAFT Polymerization of Vinyl Monomers in Supercritical Carbon Dioxide

López‐Domínguez

Jaramillo‐Soto

Vivaldo‐Lima

2018

Macro Reaction Engineering

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“…highlighted the use of Computer Aided Process Engineering (CAPE) methods and tools for systematic analysis of chemical product–process development. A good number of papers have also been published on modeling and simulation of polymerization reactions . However, the application of DEA, a mathematical approach, and Shannon's Entropy for synthesis of polysaccharide based graft copolymers has not been reported yet in literature.…”

Section: Introductionmentioning

confidence: 99%

Quantification of Optimal Reaction Parameters for the Synthesis of a Polysaccharide‐Based Graft Copolymers Using Combined Shannon's Entropy and Data Envelopment Analysis

2019

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The traditional process of synthesis of desired materials involves a trial and error approach, which consumes considerable time and resources. Therefore, it is necessary to implement computer-aided optimizing techniques for the precise synthesis of desired material. This paper presents a novel modeling approach for precise synthesis of graft copolymers of poly(acrylic acid) and Tamarind seed polysaccharide (xyloglucan). Different sets of variables generated through experimental study have been analyzed for the quantification of optimal reaction variables and parameters using combined Shannon's entropy and data envelopment analysis (DEA). Experimental data from the grafting reaction such as concentration of acrylic acid, temperature, and time are used to validate the model and a good agreement between model predictions and experimental data is observed. The proposed innovative green approach for designing the precise synthesis of xyloglucan based graft copolymers may help in identifying the optimal conditions for polymerization reaction to reach targeted materials more efficiently.

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“…A small amount of divinylbenzene in styrene polymerization makes the polymer insoluble in most of the solvents. Therefore, para-Divinylbenzene (PDVB) is used in industrial scale for the production of polystyrene ion exchange resin beads [1][2][3][4]. PDVB is produced by the catalytic dehydrogenation of para-diethyl benzene (PDEB) at higher temperature in the presence of superheated steam over iron-based supported catalyst system (Scheme 1) similar to the catalytic dehydrogenation of Ethylbenzene (EB) to styrene (ST) [5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Catalytic Dehydrogenation of para-Diethyl Benzene to para-Divinyl Benzene over Iron Oxide Supported Catalyst

Srivastava

Sharma

Jasra

2018

Bull. Chem. React. Eng. Catal.

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The vapor-phase catalytic dehydrogenation of para-diethyl benzene (PDEB) to para-divinyl benzene (PDVB) with super-heated steam as a diluent was investigated using alumina supported iron oxide catalyst system. During the catalytic dehydrogenation reaction, ethyl styrene (EST) and thermal cracking products were observed as side products. It was found that various reaction parameters influence the rate of dehydrogenation reaction. However, the reaction is favored by high temperature and low reaction pressure. Moreover, addition of potassium into iron-oxide catalyst acts as a promoter and thereby increases the efficiency of the catalyst. The conversion of PDEB and yield of PDVB also increases as the Water/PDEB flow ratio increases.

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

Cited by 19 publications

References 53 publications

A Modeling Study on the RAFT Polymerization of Vinyl Monomers in Supercritical Carbon Dioxide

A Modeling Study on the RAFT Polymerization of Vinyl Monomers in Supercritical Carbon Dioxide

Quantification of Optimal Reaction Parameters for the Synthesis of a Polysaccharide‐Based Graft Copolymers Using Combined Shannon's Entropy and Data Envelopment Analysis

Catalytic Dehydrogenation of para-Diethyl Benzene to para-Divinyl Benzene over Iron Oxide Supported Catalyst

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