Computer simulation of reactive extrusion processes for free radical polymerization

Jia, Yuxi; Zhang, Guofang; Wu, Lili; Sun, Sheng; Zhao, Guoqun; An, Lijia

doi:10.1002/pen.20739

Cited by 10 publications

(15 citation statements)

References 34 publications

(36 reference statements)

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“…An incremental theory is introduced to solve the above mentioned problems . Unfold the fluid flow space along the axial direction of the screw channel as a two‐dimensional axisymmetrical laminar flow model and then discretize it . Assuming that

X true(I, J true)

denotes the overall monomer conversion on the J th space point in the I th time step,

X true(I - 1, J true)

the overall monomer conversion on the J th space point in the

(I - 1)

th time step, and

Δ X true(I, J true)

the increment of overall monomer conversion on the J th space point in the I th time step, the following equation can be obtained:

{\frac{\partial X}{\partial t} false|}_{I, J} = \frac{Δ X (I, J)}{Δ t} + O (Δ t) = \frac{X (I, J) - X (I - 1, J)}{Δ t} + O (Δ t)

where

Δ t

denotes the time step, and

O (Δ t)

the truncation error for the finite‐difference equation.…”

Section: Kinetic Modeling Of Aa Grafting Onto Lldpementioning

confidence: 99%

“…In the simulation, the space of fluid flow was equivalently considered as a long axisymmetrical space, in which the effect of the axial motion of the solid wall on fluid flow was equivalent to the integrated effect of the screws and barrels on fluid flow. According to the construction method of the reactor model in our previous study, the equivalent length and radius of the model could be calculated.…”

Section: Setup Of Numerical Simulationmentioning

confidence: 99%

“…Numerical simulations have been devoted to reactive extrusion processes for quantitatively analyzing the reaction trend and optimizing the processing conditions . Such simulations have been performed by Motha and Seppala for the grafting of carboxylic acids and silanes to ethylene polymers, Hojabr et al for the grafting of GMA onto PE, Fukuoka for the grafting between PE and vinylsilane, Keum and White, Zhu et al, and Aguiar et al for the grafting of maleic anhydride on PP, and Zhao et al for poly[ethylene‐ co ‐(vinyl alcohol)]‐graft‐poly(Ε‐caprolactone) .…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Kinetic study on free radical grafting of polyethylene with acrylic acid by reactive extrusion

Zhang

Jia

2014

J of Applied Polymer Sci

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In the reactive extrusion process for the free radical grafting of acid monomers onto polyethylene, monomer grafting and homopolymerization occur simultaneously and interact with each other. Using an incremental theory, mathematical models of conversions for monomer grafting and homopolymerization were separately constructed to predict the grafting degree, mass of homopolymer and grafting efficiency. Effects of the barrel temperature, initial monomer and initiator concentrations on grafting behaviors were investigated. The barrel temperature and initial monomer concentration were shown to be the main process parameters for controlling the grafting degree. The grafting degree and mass of homopolymer increased significantly with increasing barrel temperature and monomer concentration and increased marginally with increasing initiator concentration. No significant improvement in the grafting efficiency was observed. The predictions of the models are in good agreement with experimental data. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40990.

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X true(I, J true)

denotes the overall monomer conversion on the J th space point in the I th time step,

X true(I - 1, J true)

the overall monomer conversion on the J th space point in the

(I - 1)

th time step, and

Δ X true(I, J true)

the increment of overall monomer conversion on the J th space point in the I th time step, the following equation can be obtained:

{\frac{\partial X}{\partial t} false|}_{I, J} = \frac{Δ X (I, J)}{Δ t} + O (Δ t) = \frac{X (I, J) - X (I - 1, J)}{Δ t} + O (Δ t)

where

Δ t

denotes the time step, and

O (Δ t)

the truncation error for the finite‐difference equation.…”

Section: Kinetic Modeling Of Aa Grafting Onto Lldpementioning

confidence: 99%

Section: Setup Of Numerical Simulationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Kinetic study on free radical grafting of polyethylene with acrylic acid by reactive extrusion

Zhang

Jia

2014

J of Applied Polymer Sci

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show abstract

“…One approach simplifies the extruder geometry into 1‐D or 2‐D model to reduce the computational load. Such approach has been adopted for the reactive extrusions of various polymerizations, including controlled degradation of polypropylene , free radical polymerization , graft copolymerization , and polymerization of L‐lactide , etc. The low dimensional models can provide average thermomechanical parameters along the extrusion, such as temperature, pressure, viscosity, etc.…”

Section: Introductionmentioning

confidence: 99%

3‐D numerical simulations for polycondensation of poly(p‐phenylene terephthalamide) in twin screw extruder

Zong

Tang

Zhao

2017

Polymer Engineering & Sci

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Poly(p-phenylene terephthalamide) (PPTA) is a typical high-performance fiber and usually synthesized by low temperature solution polycondensation in twin screw extruder. During the reactive extrusion, flow behavior, rheokinetics, and temperature are highly coupled, which makes it difficult to ensure the quality of product. In the present work, the rheokinetics of the PPTA solution is established by experiments and its reactive extrusion is investigated via 3-D numerical simulation. The flow pattern, molecular weight distribution and temperature have been investigated for the extruders with three different elements, i.e., full flight screw (FF), kneading block (KB), and screw mixing element (SME). The results indicate that the unique flow characteristic of different screw elements affects mixing experience of the reactants and further the PPTA qualities. By numerical simulation, it shows the temperature increase within the tested extrusion stage is 7 K and reaction heat is found the main energy source for extrusion stage. Furthermore, heat removal method is verified with consideration of industrial production process. The numerical simulation work also discusses the reaction and mixing process in the extruders with three combined screws. The results show the introduction of more reverse FF and KB elements can lead to higher quality of FIG. 2. Rheokinetics of PPTA during polycondensation: (a) effect of shear rate on viscosity. (b) Effect of M w on consistency index. [Color figure can be viewed at wileyonlinelibrary.com]

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“…The optimization methodology for reactive extrusion processes is still in its infancy and further researches should be performed. In our previous studies, we have built a 2D axisymmetrical model, introduced a semi‐implicit iterative algorithm and conducted the numerical simulation of reactive extrusion processes for polymerization . In this article, the reactive extrusion process for the free radical bulk polymerization was chosen as the optimization system.…”

Section: Introductionmentioning

confidence: 99%

Multi‐objective optimization of reactive extrusion by genetic algorithms

Zhang

Jia

2014

J of Applied Polymer Sci

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In reactive extrusion processes for polymerization, a multi-objective optimization model maximizing the monomer conversion whilst ensuring the low energy consumption was constructed. The selections of reactive processing conditions could be set automatically using an optimization methodology based on genetic algorithms coupled with the numerical simulation routines. Various case studies were discussed. Comparison with experimental data indicates that the design of processing conditions can be performed according to the prespecified objectives.

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Computer simulation of reactive extrusion processes for free radical polymerization

Cited by 10 publications

References 34 publications

Kinetic study on free radical grafting of polyethylene with acrylic acid by reactive extrusion

Kinetic study on free radical grafting of polyethylene with acrylic acid by reactive extrusion

3‐D numerical simulations for polycondensation of poly(p‐phenylene terephthalamide) in twin screw extruder

Multi‐objective optimization of reactive extrusion by genetic algorithms

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