Modeling and Optimization of Styrene Syndiotactic Polymerization Through Multiscale PDF Download

Author: Raheem Saad Sultan
Publisher:
ISBN:
Category : Polymerization
Languages : en
Pages : 556

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Author: R. Paulen
Publisher: Elsevier Inc. Chapters
ISBN: 012808619X
Category : Science
Languages : en
Pages : 16

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We study dynamic optimization of a lab-scale semi-batch emulsion copolymerization reactor for styrene and butyl acrylate in the presence of n-dodecyl mercaptan as chain transfer agent (CTA). The previously developed mathematical model of the polymerization reactions is used to predict the glass transition temperature of produced polymer, the global monomer conversion, the number and weight average molecular weights, the particle size distribution, and the amount of residual monomers. This model is implemented within gPROMS environment for modeling and optimization. It is desired to compute optimal profiles of feed rate of pre-emulsioned monomers and CTA which optimize properties (quantitative as well as qualitative) of polymers produced during the reaction subject to operational conditions and constraints.

Author: W. H. B. W. Ibrahim
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Dynamic modelling and optimization of three different processes namely (a) bulk polymerization of styrene, (b) solution polymerization of methyl methacrylate (MMA) and (c) emulsion copolymerization of Styrene and MMA in batch and semi-batch reactors are the focus of this work. In this work, models are presented as sets of differential-algebraic equations describing the process. Different optimization problems such as (a) maximum conversion (Xn), (b) maximum number average molecular weight (Mn) and (c) minimum time to achieve the desired polymer molecular properties (defined as pre-specified values of monomer conversion and number average molecular weight) are formulated. Reactor temperature, jacket temperature, initial initiator concentration, monomer feed rate, initiator feed rate and surfactant feed rate are used as optimization variables in the optimization formulations. The dynamic optimization problems were converted into nonlinear programming problem using the CVP techniques which were solved using efficient SQP (Successive Quadratic Programming) method available within the gPROMS (general PROcess Modelling System) software. The process model used for bulk polystyrene polymerization in batch reactors, using 2, 2 azobisisobutyronitrile catalyst (AIBN) as initiator was improved by including the gel and glass effects. The results obtained from this work when compared with the previous study by other researcher which disregarded the gel and glass effect in their study which show that the batch time operation are significantly reduced while the amount of the initial initiator concentration required increases. Also, the termination rate constant decreases as the concentration of the mixture increases, resulting rapid monomer conversion. The process model used for solution polymerization of methyl methacrylate (MMA) in batch reactors, using AIBN as the initiator and Toluene as the solvent was improved by including the free volume theory to calculate the initiator efficiency, f. The effects of different f was examined and compared with previous work which used a constant value of f 0.53. The results of these studies show that initiator efficiency, f is not constant but decreases with the increase of monomer conversion along the process. The determination of optimal control trajectories for emulsion copolymerization of Styrene and MMA with the objective of maximizing the number average molecular weight (Mn) and overall conversion (Xn) were carried out in batch and semi-batch reactors. The initiator used in this work is Persulfate K2S2O8 and the surfactant is Sodium Dodecyl Sulfate (SDS). Reduction of the pre-batch time increases the Mn but decreases the conversion (Xn). The sooner the addition of monomer into the reactor, the earlier the growth of the polymer chain leading to higher Mn. Besides that, Mn also can be increased by decreasing the initial initiator concentration (Ci0). Less oligomeric radicals will be produced with low Ci0, leading to reduced polymerization loci thus lowering the overall conversion. On the other hand, increases of reaction temperature (Tr) will decrease the Mn since transfer coefficient is increased at higher Tr leading to increase of the monomeric radicals resulting in an increase in termination reaction.

Author: Kam Yok Loke
Publisher:
ISBN:
Category : Emulsion polymerization
Languages : en
Pages : 67

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Book Description
This paper studies the optimization of emulsion copolymerization of Styrene and Methyl Methacrylate (MMA). A model-based framework for optimal operation of copolymerization processes was used in gPROMS environment and enables us to predict the maximum monomer conversion for a given total monomer feed over the batch time. The complexities of the process were represented by mathematical models for optimization and control. A process model involving the equations for mass and energy balance describing the particle evolution in a batch reactor and diffusion controlled kinetics is incorporated into the optimization framework. The modeling is account for complex physic-chemical sub-processes involving particle formation mechanisms with two monomer droplets, surfactants, initiator and particulates. Using gPROMS, the system analyzed the data, created models, developed algorithms, manipulated and plotted based on the functions and data. The determination of optimal profile for control variables used for emulsion polymerization of styrene and MMA that yielded desired conversion with fixed batch time and fixed number average molecular weight in batch reactor respectively were carried out in batch reactor. Reduction of the pre-batch time increases the Mn but decreases the conversion (Xn). The faster the addition of monomer into the reactor, the earlier the growth of the polymer chain leading to higher Mn. The increases of the reaction temperature will decrease the Mn since increases of temperature will increase the rate of termination reaction.

Author: Francis Michael C. Perez
Publisher:
ISBN:
Category : Catalysis
Languages : en
Pages : 218

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Author: Michael Kotelyanskii
Publisher: CRC Press
ISBN: 0824751310
Category : Technology & Engineering
Languages : en
Pages : 572

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Author: Khouloud Jlassi
Publisher: Elsevier
ISBN: 0323461611
Category : Technology & Engineering
Languages : en
Pages : 548

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Book Description
Clay–Polymer Nanocomposites is a complete summary of the existing knowledge on this topic, from the basic concepts of synthesis and design to their applications in timely topics such as high-performance composites, environment, and energy issues. This book covers many aspects of synthesis such as in- situ polymerization within the interlamellar spacing of the clays or by reaction of pristine or pre-modified clays with reactive polymers and prepolymers. Indeed, nanocomposites can be prepared at industrial scale by melt mixing. Regardless the synthesis method, much is said in this book about the importance of theclay pre-modification step, which is demonstrated to be effective, on many occasions, in obtaining exfoliated nanocomposites. Clay–Polymer Nanocomposites reports the background to numerous characterization methods including solid state NMR, neutron scattering, diffraction and vibrational techniques as well as surface analytical methods, namely XPS, inverse gas chromatography and nitrogen adsorption to probe surface composition, wetting and textural/structural properties. Although not described in dedicated chapters, numerous X-ray diffraction patterns of clay–polymer nanocomposites and reference materials are displayed to account for the effects of intercalation and exfoliations of layered aluminosilicates. Finally, multiscale molecular simulation protocols are presenting for predicting morphologies and properties of nanostructured polymer systems with industrial relevance. As far as applications are concerned, Clay–Polymer Nanocomposites examines structural composites such as clay–epoxy and clay–biopolymers, the use of clay–polymer nanocomposites as reactive nanocomposite fillers, catalytic clay-(conductive) polymers and similar nanocomposites for the uptake of hazardous compounds or for controlled drug release, antibacterial applications, energy storage, and more. The most comprehensive coverage of the state of the art in clay–polymer nanocomposites, from synthesis and design to opportunities and applications Covers the various methods of characterization of clay–polymer nanocomposites - including spectroscopy, thermal analyses, and X-ray diffraction Includes a discussion of a range of application areas, including biomedicine, energy storage, biofouling resistance, and more

Author: Kishore V. Pochiraju
Publisher: Springer Science & Business Media
ISBN: 1441993088
Category : Technology & Engineering
Languages : en
Pages : 681

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Long-Term Durability of Polymeric Matrix Composites presents a comprehensive knowledge-set of matrix, fiber and interphase behavior under long-term aging conditions, theoretical modeling and experimental methods. This book covers long-term constituent behavior, predictive methodologies, experimental validation and design practice. Readers will also find a discussion of various applications, including aging air craft structures, aging civil infrastructure, in addition to engines and high temperature applications.

Author: Masami Okamoto
Publisher: iSmithers Rapra Publishing
ISBN: 9781859573914
Category : Science
Languages : en
Pages : 190

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Book Description
The review sets out to highlight the major developments in this field over the last decade. The different techniques used to prepare PLS nanocomposites are covered. The physicochemical characterisation of PLS nanocomposites and the improved materials properties that those materials can display are discussed. An additional indexed section containing several hundred abstracts from the Rapra Polymer Library database provides useful references for further reading.

Author: Purushottam D. Gujrati
Publisher: John Wiley & Sons
ISBN: 9783527630264
Category : Technology & Engineering
Languages : en
Pages : 564

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Book Description
Filling a gap in the literature and all set to become the standard in this field, this monograph begins with a look at computational viscoelastic fluid mechanics and studies of turbulent flows of dilute polymer solutions. It then goes on discuss simulations of nanocomposites, polymerization kinetics, computational approaches for polymers and modeling polyelectrolytes. Further sections deal with tire optimization, irreversible phenomena in polymers, the hydrodynamics of artificial and bacterial flagella as well as modeling and simulation in liquid crystals. The result is invaluable reading for polymer and theoretical chemists, chemists in industry, materials scientists and plastics technologists.