Fabrício Machado - Academia.edu (original) (raw)
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Papers by Fabrício Machado
Industrial Crops and Products, 2015
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Computer Aided Chemical Engineering, 2009
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Computer Aided Chemical Engineering, 2009
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Polimeros-ciencia E Tecnologia, 2007
Several processes can be employed for manufacturing polymer materials. Each process presents some... more Several processes can be employed for manufacturing polymer materials. Each process presents some intrinsic features that lead to production of resins with peculiar properties, which define the end-use application of the final polymeric material. Suspension polymerization processes are extensively used because of their many advantages, such as the easy separation of the polymer particles, easy removal of the heat of reaction, easy temperature control and low levels of impurities and additives in the final polymer material. For this reason, suspension polymerization processes are suitable to produce polymer resins for biotechnological and medical applications. The main objective of this work is to discuss the fundamental aspects of suspension polymerization processes, focusing upon the effects of the main process variables on the performance of suspension polymerizations. Additionally, it is shown that near infrared spectroscopy (NIRS) can be useful for monitoring and real time control of suspension processes, allowing for production of polymer beads with controlled morphology.
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Polymer Engineering and Science, 2009
This work performs the dynamic optimization of semibatch vinyl acetate (VAc)/acrylic acid (AA) su... more This work performs the dynamic optimization of semibatch vinyl acetate (VAc)/acrylic acid (AA) suspension copolymerizations. The proposed dynamic optimization strategy is based on a direct search Complex algorithm and is used to control the copolymer composition along the batch. First, a sequential optimization procedure is used to determine the optimum AA concentration and feed rate profiles, required to provide the specified copolymer composition. In the second step, a sequential optimization procedure is coupled with a predictive controller to guarantee that the manipulation of feed flow rates can allow for attainment of the desired copolymer compositions. The optimization strategy is validated through simulation, by assuming that reactions are subject to perturbations of the reaction temperature, initiator, and VAc concentrations. It is shown that the proposed optimization strategy can be used successfully both for design of monomer feed rate profiles and removal of process disturbances during semibatch suspension copolymerizations, to keep the copolymer composition constant throughout the batch. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
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European Polymer Journal, 2008
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European Polymer Journal, 2008
Sequential polymerizations were carried out using a high-activity MgCl2/Ziegler–Natta catalyst to... more Sequential polymerizations were carried out using a high-activity MgCl2/Ziegler–Natta catalyst to evaluate whether the in situ preparation of polypropylene/1-butene alloys was possible inside the reaction vessel and analyze the effects of 1-butene on the final material properties. Propylene/1-butene alloy resins were synthesized in a sequential two-stage process. In the first stage, liquid pool propylene polymerizations were carried out in batch. In the second stage, 1-butene was polymerized inside the polypropylene matrix in gas-phase in semibatch mode. According to the obtained results, it is possible to incorporate 1-butene upon the polypropylene matrix inside the reactor at very low pressures, without affecting the properties of the continuous polypropylene matrix significantly.
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Polímeros, 2011
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Polímeros, 2007
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Polímeros, 2009
ABSTRACT
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Encyclopedia of Polymer Science and Technology, 2002
ABSTRACT
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This article introduces the use of in-line and in situ monitoring of the dynamic evolution of PVC... more This article introduces the use of in-line and in situ monitoring of the dynamic evolution of PVC morphological properties in suspension polymerization reactions based on near infrared spectroscopy (NIRS) intended for control applications. It is shown for the first time that it is possible to follow the dynamic evolution of morphological properties (such as the bulk density, BD, and the cold plasticizer absorption, CPA) in real time. The obtained results indicate that closed-loop control schemes can be properly implemented to control end-use resin properties, which depend upon the morphology of PVC polymer particles. Suspension polymerization of vinyl chloride performed in bench and pilot scale showed that process variables, such as the agitation speed and the amount of suspending agents) can be successfully manipulated in order to control the morphological parameters of PVC resin. Based on this information, a control scheme for these parameters is proposed.
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The monitoring of polymer properties is frequently performed through sampling and off-line measur... more The monitoring of polymer properties is frequently performed through sampling and off-line measurement of quality parameters in lab scale. Because of the long time required to perform off-line analyses, off-line data are generally inadequate for control purposes. As impurities cannot be detected in-line and can exert significant influence on the polymerization kinetics, modifications of some important quality parameters (such as the morphological characteristics of PVC particles) can only be detected at the end of the polymerization, causing major production losses. In the present work it is shown for the first time that it is possible to monitor some of the morphological properties of PVC (such as the bulk density, BD, the cold plasticizer absorption, CPA, and the average particle diameter Dp) in situ and in real time with the help of near infrared spectroscopy (NIRS) in suspension polymerization processes.
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Polymer Engineering & Science, 2010
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Polymer Engineering & Science, 2011
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Macromolecular Symposia, 2011
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Macromolecular Reaction Engineering, 2009
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Macromolecular Reaction Engineering, 2011
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Macromolecular Reaction Engineering, 2010
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Macromolecular Reaction Engineering, 2010
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Industrial Crops and Products, 2015
ABSTRACT
Bookmarks Related papers MentionsView impact
Computer Aided Chemical Engineering, 2009
Bookmarks Related papers MentionsView impact
Computer Aided Chemical Engineering, 2009
Bookmarks Related papers MentionsView impact
Polimeros-ciencia E Tecnologia, 2007
Several processes can be employed for manufacturing polymer materials. Each process presents some... more Several processes can be employed for manufacturing polymer materials. Each process presents some intrinsic features that lead to production of resins with peculiar properties, which define the end-use application of the final polymeric material. Suspension polymerization processes are extensively used because of their many advantages, such as the easy separation of the polymer particles, easy removal of the heat of reaction, easy temperature control and low levels of impurities and additives in the final polymer material. For this reason, suspension polymerization processes are suitable to produce polymer resins for biotechnological and medical applications. The main objective of this work is to discuss the fundamental aspects of suspension polymerization processes, focusing upon the effects of the main process variables on the performance of suspension polymerizations. Additionally, it is shown that near infrared spectroscopy (NIRS) can be useful for monitoring and real time control of suspension processes, allowing for production of polymer beads with controlled morphology.
Bookmarks Related papers MentionsView impact
Polymer Engineering and Science, 2009
This work performs the dynamic optimization of semibatch vinyl acetate (VAc)/acrylic acid (AA) su... more This work performs the dynamic optimization of semibatch vinyl acetate (VAc)/acrylic acid (AA) suspension copolymerizations. The proposed dynamic optimization strategy is based on a direct search Complex algorithm and is used to control the copolymer composition along the batch. First, a sequential optimization procedure is used to determine the optimum AA concentration and feed rate profiles, required to provide the specified copolymer composition. In the second step, a sequential optimization procedure is coupled with a predictive controller to guarantee that the manipulation of feed flow rates can allow for attainment of the desired copolymer compositions. The optimization strategy is validated through simulation, by assuming that reactions are subject to perturbations of the reaction temperature, initiator, and VAc concentrations. It is shown that the proposed optimization strategy can be used successfully both for design of monomer feed rate profiles and removal of process disturbances during semibatch suspension copolymerizations, to keep the copolymer composition constant throughout the batch. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Bookmarks Related papers MentionsView impact
European Polymer Journal, 2008
Bookmarks Related papers MentionsView impact
European Polymer Journal, 2008
Sequential polymerizations were carried out using a high-activity MgCl2/Ziegler–Natta catalyst to... more Sequential polymerizations were carried out using a high-activity MgCl2/Ziegler–Natta catalyst to evaluate whether the in situ preparation of polypropylene/1-butene alloys was possible inside the reaction vessel and analyze the effects of 1-butene on the final material properties. Propylene/1-butene alloy resins were synthesized in a sequential two-stage process. In the first stage, liquid pool propylene polymerizations were carried out in batch. In the second stage, 1-butene was polymerized inside the polypropylene matrix in gas-phase in semibatch mode. According to the obtained results, it is possible to incorporate 1-butene upon the polypropylene matrix inside the reactor at very low pressures, without affecting the properties of the continuous polypropylene matrix significantly.
Bookmarks Related papers MentionsView impact
Polímeros, 2011
Bookmarks Related papers MentionsView impact
Polímeros, 2007
Bookmarks Related papers MentionsView impact
Polímeros, 2009
ABSTRACT
Bookmarks Related papers MentionsView impact
Encyclopedia of Polymer Science and Technology, 2002
ABSTRACT
Bookmarks Related papers MentionsView impact
This article introduces the use of in-line and in situ monitoring of the dynamic evolution of PVC... more This article introduces the use of in-line and in situ monitoring of the dynamic evolution of PVC morphological properties in suspension polymerization reactions based on near infrared spectroscopy (NIRS) intended for control applications. It is shown for the first time that it is possible to follow the dynamic evolution of morphological properties (such as the bulk density, BD, and the cold plasticizer absorption, CPA) in real time. The obtained results indicate that closed-loop control schemes can be properly implemented to control end-use resin properties, which depend upon the morphology of PVC polymer particles. Suspension polymerization of vinyl chloride performed in bench and pilot scale showed that process variables, such as the agitation speed and the amount of suspending agents) can be successfully manipulated in order to control the morphological parameters of PVC resin. Based on this information, a control scheme for these parameters is proposed.
Bookmarks Related papers MentionsView impact
The monitoring of polymer properties is frequently performed through sampling and off-line measur... more The monitoring of polymer properties is frequently performed through sampling and off-line measurement of quality parameters in lab scale. Because of the long time required to perform off-line analyses, off-line data are generally inadequate for control purposes. As impurities cannot be detected in-line and can exert significant influence on the polymerization kinetics, modifications of some important quality parameters (such as the morphological characteristics of PVC particles) can only be detected at the end of the polymerization, causing major production losses. In the present work it is shown for the first time that it is possible to monitor some of the morphological properties of PVC (such as the bulk density, BD, the cold plasticizer absorption, CPA, and the average particle diameter Dp) in situ and in real time with the help of near infrared spectroscopy (NIRS) in suspension polymerization processes.
Bookmarks Related papers MentionsView impact
Polymer Engineering & Science, 2010
Bookmarks Related papers MentionsView impact
Polymer Engineering & Science, 2011
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Macromolecular Symposia, 2011
Skip to Main Content. ...
Bookmarks Related papers MentionsView impact
Macromolecular Reaction Engineering, 2009
Bookmarks Related papers MentionsView impact
Macromolecular Reaction Engineering, 2011
Bookmarks Related papers MentionsView impact
Macromolecular Reaction Engineering, 2010
Bookmarks Related papers MentionsView impact
Macromolecular Reaction Engineering, 2010
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