Computational And Experimental Investigation Of Free Radical Polymerization Of Styrene Using A Multifunctional Initiator

Lately, the study of peroxides multifunctional initiators has been explored in the scientific and industrial field. These initiators are able to increase the reaction rate in a free radical polymerization without decrease the molecular weight of the formed polymer. Besides that they can also generate branches in the polymeric chain, changing the polymer structure. Copyright © 2009, AIDIC Servizi S.r.l.1718011806Machado P.F.M.P.B.Lona, L.M.F.,2005, Development of a Software to Simulate Free Radical Polymerization of Linear and Branched Polymers using Mono-and Bi-Functional Initiators, E. Symp. on Comp. Aided Proc. Eng.-15, 2005, 20 A, 445-450Scorah, M.J., (2005) Modelling of Free Radical Polymerization of Styrene and Methyl Methacrylate by a Tetrafunctional Initiator, , PhD thesis, Dept. of Chem. Eng, University of Waterloo, Waterloo, Ontario, CanadaScorah, M. J.Dhib, R.Penlidis, A., 2007, Recent Advances in the Study of Multifunctional Initiators in Free Radical Polymerizations, Macrom. React. Eng., 1, 209-22

The fluidized bed reactor with a prepolymerization system and its influence on polymer physicochemical characteristics

This work addresses the influence of a prepolymerization system on the behavior of the fluidized bed reactor used for polyethylene production. Its influence on the polymer's physicochemical characteristics and production was also studied. The results indicate that the use of prepolymerized catalyst particles results in milder temperatures in the fluidized bed reactor, thus avoiding the formation of hot spots, melting of the polymer particle and reactor shutdown. Productivity can be enhanced depending on the operational conditions used in the prepolymerization reactor

Cyclic Trifunctional Peroxide On Living Free Radical Polymerization

Until the mid 90's, free radical polymerization (FRP) was characterized by producing polymers with high average molecular weig hts (1×10 5-1×106) since the beginning of polymerization, index of polidispersity (PDI) greater than 1.5 and wide molecular weight distribution (MWD). When necessary to produce polymers with more defined structure, it was usually used anionic polymerization, which is capable to produce polymers with narrow molecular weight distribution and PDI around 1.0 (1.1-1.2). The ionic polymerization, however, needs to be held in a high degree of purity and in the absence of inhibitors, what make the ionic polymerization expensive and not very practical from the industrial point of view. A promising alternative to ionic polymerization has been the living radical polymerization (LFRP), which is much more robust to the impurities and kind of solvent and it is able to produce polymers with polidispersity close to one. Nevertheless, the LFRP presents lower polymerization rates compared to standard and smaller polymer chains (lower molecular weights averages). In this work the effect of cyclic trifunctional initiator on the Living Free Radical Polymerization is analyzed. The Nitroxide Mediated Radical Polymerization (NMRP) is considered, using TEMPO as controller and styrene as monomer. It can be observed that the polidispersity can vary in a very broad range when this initiator is used, changing from PDI lower than 1.5 until PDI bigger than 4.0, depending on the operating conditions considered. Copyright © 2009, AIDIC Servizi S.r.l.17169174Cerna, J.R., Morales, G., Eyler, G.N., Canizo, A.I., Bulk Polymerization of Styrene Catalyzed by Bi- and Trifunctional Cyclic Initiators (2002) J. Applied Polymer Sci, 83, pp. 1-11Dias, R.S., Gonçalvez, M.C., Lona, L.M.F., Vivaldo-Lima, E., McManus, N.T., Penlidis, A., Nitroxide - Mediated Radical Polymerization of Styrene Using Mono and Di - Functional Initiators (2006) Chemical Engineering Science, , 16 Decembe

The fluidized bed reactor with a prepolymerization system and its influence on polymer physicochemical characteristics

This work addresses the influence of a prepolymerization system on the behavior of the fluidized bed reactor used for polyethylene production. Its influence on the polymer's physicochemical characteristics and production was also studied. The results indicate that the use of prepolymerized catalyst particles results in milder temperatures in the fluidized bed reactor, thus avoiding the formation of hot spots, melting of the polymer particle and reactor shutdown. Productivity can be enhanced depending on the operational conditions used in the prepolymerization reactor.171179Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Reactor Modeling And Physical-chemical Properties Characterization In Polyethylene Fluidized-bed Reactor

[No abstract available]433621624Choi, K.Y., Ray, W.H., The dynamic behaviour of fluidized bed reactors for solid catalyzed gas phase olefin polymerization (1985) Chem.Eng.Sci., 40, pp. 2261-2279DeCarvalho, A.B., Gloor, P.E., Hamielec, A.E., A Kinectic Mathematical Model for Heterogeneous Ziegler-Natta Copolymerization (1989) Polymer, 30, p. 280Kissin, Y.V., (1987) Isospecific Polymerization of Olefins with Heterogeneous Ziegler-Natta Catalysts, , Springer-Verlag, New YorkMcAuley, K.B., MacGregor, J.F., Hamielec, A.E., A kinetic model for industrial gas-phase ethylene copolymerization (1990) A.I.Ch.E.J., 36 (6), pp. 837-850McAuley, K.B., Talbot, J.P., Harris, T.J., A comparison of two-phase and well-mixed models for fluidized-bed polyethylene reactors (1994) Chem.Eng.Sci., 49 (13), pp. 2035-2045Zabisky, R.C.M., Chan, W.M., Gloor, P.E., Hamielec, A.E., A kinetic model for olefin polymerization in high-pressure tubular reactors: A review and update (1992) Polymer, 33, pp. 2243-226

Synthesis Of Heat Exchanger Networks Considering Stream Splitting And The Rigorous Calculation Of The Heat Transfer Coefficient According To The Bell Delaware Method

On the context of cost minimization and maximum profit, connected to the interest about the preservation of the environment we live in, the minimization of energy consumption in a chemical industry is placed according to the new market trends. The concept of Pinch Analysis fits in this new scenery as a tool to define the least quantity of hot and cold utilities, as well as the number of heat exchangers to be used in the plant, in order to use the energy of the own process for the many heat exchange operations going on this process. On the present work, a software was developed to work with the heuristics of Pinch Analysis and with the concept of Problem Table, to detect the Pinch temperatures. This software defines a Heat Exchanger Network (HEN) for the process and consider the stream splitting taking into account the economic evaluation of this procedure which focus on the maximum energy recovery compared with the results obtained for the case of not splitting the streams. This analysis is based on the calculation of the minimum heat transfer area and the cost of the equipment which are compared with the costs involving hot and cold utilities usage. Another aspect that was taken into account was the calculation of the heat transfer coefficient according to the Bell Delaware method for the shell side and the comparison between the results obtained by using its value. © 2000 Elsevier B.V. All rights reserved.8C10271032Ahmad, S., Linhoff, B., Smith, R., Cost Optimum Heat Exchanger Networks-Part 2 (1990) Computers Chem. Engng., 14 (No 7), pp. 751-767Hall, S.G., Ahmad, S., Simth, R., Capital Costs Targets for Heat Exchanger Networks Comprising Mixed Materials of Construction, Pressure Ratings and Exchanger Types (1990) Computers Chem. Engng., 14 (no 3), pp. 319-335Linhoff, B., Ahamd, S., Cost Optimum Heat Exchanger Networks-Minimum Energy and Capital using simple Models for Capital Cost (1990) Computers Chem. Engng, 14 (num. 7), pp. 729-750Polley, G.T., Panjeh Shahi, M.H., Interfacing Heat Exchangers Networks Synthesis and Detailed Heat Exchanger Design (1991) Trans I Chem E, 69, pp. 445-457Polley, G.T., Selecting Stream Splits in Heat Exchanger Network Design (1995) Heat Recovery Systems & HCP, 15 (no 1), pp. 85-9

Tempo-mediated Polymerization Of Styrene Using Mono And Bifunctional Initiators

With the purpose of enhancing the reaction rate of nitroxide-mediated radical polymerization of styrene (NMRP) in presence of TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy), keeping the livingness of the system, the effect of a bi-functional initiator has been examined, a new approach. The monomer used was the styrene, the stable radical was TEMPO, the mono-functional initiators were BPO and Luperox TBEC, and the bi-functional initiator was Luperox L531. The polymerization reactions were carried out in ampoules at 125°C, according to the bi-molecular technique. The conversion was evaluated by a gravimetric method, and the molecular weight distribution and the polydispersity of the polymer were analyzed by SEC (Size-Exclusion Chromatography). The effects of the use of the bifunctional initiator and the mono-functional ones with different half-life times have been evaluated. It was demonstrated that by using the bi-functional initiator L531, the reaction rate was increased when comparing to the performance of the mono-functional initiatiors, under the conditions of the reaction.Georges, M.K., Veregin, R.P., Kasmaier, P.M., Hamer, G.K., (1993) Macromolecules, 26, p. 2987Veregin, R.P.N., Odell, P.G., Michalak, L.M., Georges, M.K., (1996) Macromolecules, 29, p. 3346Butté, A., Storti, G., Mobidelli, M., (1999) Chemical Engineering Science, 54, pp. 3225-3231Solomon, D.H., Rizzardo, E., Cacioli, P.U.S., (1986) Pat, 4, pp. 581-429Vilallobos, M.A., Hamielec, A.E., Wood, P.E., (1991) Journal of Applied Polymer Science, 42 (3), pp. 629-641Benbachir, M., Benjelloun, D., (2001) Polymer, 42, pp. 7727-7738Asteasuain, M., Brandolin, A., Sarmoria, C., (2004) Polymer, 45, pp. 321-335Penlidis, A., Gao, J., Dhib, R., (2000) Polymer Reaction Engineering, 8 (4), pp. 299-246Sanchez, J., Myers, T., Peroxides and Peroxide Compounds: Organic Peroxides (1996) Kirk-Othmer Encyclopedia of Chemical Technology, 18. , 4 th ed. WileyInitiators: Free Radical Peroxides, ibid, 13., 1996Fukuda, T., Goto, A., (1997) Macromolecules, 30, p. 4272Matyjaszewsky, K., Greszta, D., (1997) Journal of Polymer Science, Part A: Polymer Chemistry, 35, p. 185

Fluidized-bed Reactor And Physicalchemical Properties Modeling For Polyethylene Production

A new steady-state model incorporating interactions between separate bubble and emulsion phases inside the reactor bed and a polymer physical-chemical characterization model were developed. A computer program, FBPOL, was also developed to accomplish the linkage of these two models, in order to predict the polymer grade that can be produced by different operational conditions. © 1999 Elsevier Science Ltd.23SUPPL. 1S803S806Choi, K.Y., Ray, W.H., The Dynamic Behaviour of Fluidized Bed Reactors for Solid Catalyzed Gas Phase Olefin Polymerization (1985) Chem.Eng.Sci., 40, pp. 2261-2279deCarvalho, A.B., Gloor, P.E., Hamielec, A.E., A Kinetic Mathematical Model for Heterogeneous Ziegler-Natta Copolymerization (1989) Polymer, 30, p. 280Kissin, Y.V., (1987) Isospecijic Polymerization of Olefins with Heterogeneous Ziegler-Natta Catalysts, , SpringerVerlag, New YorkMcAuley, K.B., MacGregor, I.F., Hamielec, A.E., A Kinetic Model for Industrial Gas-Phase Ethylene Copolymerization (1990) A. J. Ch. E. J., 36, pp. 837-850McAuley, K.B., Talbot, J.P., Harris, T.J., A Comparison of Two-Phase and Well-Mixed Models for Fluidized-Bed Polyethylene Reactors (1994) Chem. Eng. Sci., 49, pp. 2035-2045Zabisky, R.C.M., Chan, W.M., Gloor, P.E., Hamielec, A.E., A Kinetic Model for Olefin Polymerization in High-Pressure Tubular Reactors: a Review and Update (1992) Polymer, 33, pp. 2243-226

Synthesis And Characterization Of Polystyrene/layered Hydroxide Salt Nanocomposites [síntese E Caracterização De Nanocompósitos De Poliestireno/hidroxissal Lamelar]

Polystyrene/layered hydroxide salt (LHS) modified with sodium dodecyl sulfate was synthesized by in situ polymerization. The materials synthesized were characterized by gravimetry, X-ray diffraction (XRD), thermogravimetry analyses (TGA), differential scanning calorimetry (DSC) and the flammability test (FT). XRD demonstrated that synthesized nanocomposites in all compositions studied showed poor global dispersion of LHS in polystyrene. TGA showed a slight decrease in thermal stability. DSC curves showed that the glass transition temperature of polystyrene and nanocomposites were similar. The FT showed that the nanocomposite with low load of LHS exhibited good results.3711821Botan, R., Nogueira, T.R., Lona, L.M.F., Wypych, F., (2011) Polímeros, 21, p. 34Souza, M.A., Pessan, L.A., Rodolfo, Jr.A., (2006) Polímeros, 16, p. 257Nogueira, T., Botan, R., Wypych, F., Lona, L., (2011) Composites Part A, 42, p. 1025Camargo, P.H.C., Satyanarayana, K.G., Wypych, F., (2009) Mater. Res., 12, p. 1Arizaga, G.G.C., Satyanarayana, K.G., Wypych, F., (2007) Solid State Ionics, 178, p. 1143Alexandre, M., Dubois, P., (2000) Mater. Sci. Eng., 28, p. 1Pavlidou, S., Papaspyrides, C.D., (2008) Prog. Polym. Sci., 33, p. 1119Yano, K., Usuki, A., Okada, A., Kurauchi, T., Kamigaito, O., (1993) J. Polym. Sci., Part A: Polym. Chem., 31, p. 2493Esteves, A.C.C., Barros-Timmons, A., Trindade, T., (2004) Quim. Nova, 27, p. 798Nogueira, T., Botan, R., Wypych, F., Lona, L., (2012) J. Appl. Polym. Sci., 124, p. 1764Vaia, R.A., Teukolsky, R.K., Giannelis, E.P., (1994) Chem. Mater., 6, p. 1017Avalos, F., Ortiz, J.C., Zitzumbo, R., López-Manchado, M.A., Verdejo, R., Arroyo, M., (2008) Eur. Polym. J., 44, p. 3108Leite, I.F., Malta, O.L., Raposo, C.M.O., Canedo, L.E., Carvalho, L.H., Silva, S.M.L., (2011) Polímeros, 21, p. 195Marangoni, R., Ramos, L.P., Wypych, F., (2009) J. Colloid Interface Sci., 330, p. 303Botan, R., Nogueira, T.R., Wypych, F., Lona, L.M.F., (2012) Polym. Eng. Sci., 52, p. 1754Kotal, M., Kuila, T., Srivastava, S.K., Bhowmick, A.K., (2009) J. Appl. Polym. Sci., 114, p. 2691Qiu, L., Chen, W., Qu, B., (2005) Colloid Polym. Sci., 283, p. 1241Qiu, L., Chen, W., Qu, B., (2005) Polym. Degrad. Stab., 87, p. 433http://www.boedeker.com/bpi-ul94.htm, acessada em Setembro 2013Nogueira, T., Botan, R., Neto, J.C.M., Wypych, F., Lona, L., (2013) Adv. Polym. Tech., 32, pp. E66

Development Of Ducts By Filament Winding: A Study Through The Neural Networks [desenvolvimento De Dutos Por Filament Winding: Um Estudo Através De Redes Neurais]

Currently, the sector of polymeric composites is one of the most promising ones, due to the many advantages of these materials. Among the methods of manufacture, one that is very important is filament winding, which allows for the production of parts that are commonly employed in the oil industry, such as ducts, tanks, and risers. One of the major restrictions related to a larger scale exploration of these methods, including the filament winding, is the difficulty in relating the several process parameters necessary for their manufacture, with the quality of the final product and the efficiency of the production. Neural networks were applied to the process of filament winding in two cases: estimation of the properties that describe the quality of the final product from industrial assays for experimental characterization and forecast of the thermal behavior of ducts during the curing stage, from the data generated by the Lee-Springer model. Computational programs were developed for the training of the networks, and the effect of each input variable was determined. The application of neural networks in the modeling of the process of filament winding may lead to a better comprehension of the process, to a reduction in the time needed for the development of products, and in the cost of the ducts.4711538(2000) Revista do Plástico Reforçado, (16), p. 12. , novembro/dezembroGibson, A.G., (2000) Comprehensive Composite Materials: Design and Applications. 1.Ed., 6, pp. 459-478. , Inglaterra: Elsevier. Cap. 6.23: Composite materials in the offshore industryMohitpour, M., Glover, A., Trefanenko, B., Technology advances key worldwide gas pipeline developments (2001) Oil and Gas Journal, 26, pp. 60-67. , novembroMatthews, F.L., Rawlings, R.D., (1996) Composites Materials: Engineering and Science, , Reino Unido: Chapman & Hall, 470pTarnopol'skii, Y.M., Kulakov, V.L., Mungalov, D.D., Composites in offshore technology in the next century (1999) Mechanics of Composite Materials, 35 (5), pp. 365-372Boothby, P.J., Johnstone, C.D., Fibre-reinforced caissons for offshore applications (1997) Composite Structure, 38 (1-4), pp. 141-149Kitching, R., Tang, W.M., Comparasion of glass reinforced plastic T-junction/straight pipe combinations for offshore use (1997) International Journal of Pressure Vessels and Piping, 71, pp. 263-283Baughman, D.R., Liu, Y.A., (1995) Neural Networks in Bioprocessing and Chemical Engineering, , EUA: Academic Press, 488pLee, S., Springer, G.S., Filament winding cylinders: I. Process model (1990) Journal of Composite Materials, 24, pp. 1270-1298Boger, Z., Experience in industrial plant model development using large-scale artificial neural networks (1997) Information Sciences, 101, pp. 203-216Lona Batista, L.M.F., (1996) Desenvolvimento de Software Usando Modelos Determinísticos e Redes Neurais para o Processo de Craqueamento Catalítico, , Campinas: Faculdade de Engenharia Química, UNICAMP. 256 p. Tese (Doutorado)Konderla, P., Mokanek, T., Comparasion of two methods for the analysis of composite material (2000) Journal of Materials Processing Technology, 106, pp. 87-93Lee, J.A., Almond, D.P., Harris, B., (1999) The Use of Neural Networks for the Prediction of Fatigue Lives of Composite Materials. Composites: Part A, 30, pp. 1159-1169Wilcox, J.A.D., Wright, D.T., Towards pultrusion process optimization using artificial neural networks (1998) Journal of Materials Processing Technology, 83 (1), pp. 131-141Sumpter, B.G., Noid, D.W., On the design, analysis, and characterization of materials using computational neural networks (1996) Annual Review of Material Science, 26, pp. 223-277Haykin, S., (2001) Redes Neurais, Princípios e Práticas. 2.Ed., , Porto Alegre: Bookman, 900 pHaykin, S., (1994) Neural Networks, a Comprehensive Foundation, , EUA: Macmillan College, 696 pContant, S., (2002) Aplicação de Redes Neurais no Processo de Filament Winding, , Campinas: Faculdade de Engenharia Química, UNICAMP. 108 p. Tese (Mestrado)Garson, G.D., Interpreting neural-networks connection weights (1991) AI Expert, pp. 47-59. , abrilSoutham, D., Filamet wound pipe, an economic solution (2000) Reinforced Plastics, pp. 40-43. , julho/agostoBannister, M., (2001) Challenges for Composites in the Next Millennium - A Reinforcement Perspective. Composites: Part A, 2, pp. 901-910Agarwal, B.D., Broutman, L.J., (1990) Analysis and Performance of Fiber Composites. 2.Ed., , EUA: John Wiley & Sons, 472 pPeters, S.T., Humphrey, D.W., (1989) Engineered Materials Handbook: Composites, 1, pp. 503-518. , EUA: ASM: Filament windingBanerjee, A., Sun, L., Mantell, S.C., Cohen, D., (1998) Model and Experimental Study of Fiber Motion in Wet Filament Winding. Composites: Part A, 29 A, pp. 251-263Agah-Tehrani, A., Teng, H., Analysis of fiber motion during wet filament winding of composite cylinders with arbitrary thickness (1992) International Journal of Solids Structures, 29 (21), pp. 2649-2668Mazumdar, S.K., Hoa, S.V., Analytical models for low cost manufacturing of composite components by filament winding, part I: Direct kinematics (1995) Journal of Composite Materials, 29 (11), pp. 1515-1541Mazumdar, S.K., Hoa, S.V., Analytical models for low cost manufacturing of composite components by filament winding, part II: Inverse kinematics (1995) Journal of Composite Materials, 29 (13), pp. 1762-1789Zhao, L., Mantell, S.C., Cohen, D., McPeak, R., Finite element modeling of the filament winding process (2001) Composite Structures, 52, pp. 499-510Parnas, L., Katirci, N., Design of fiber-reinforced composite pressure vessels under various loading conditions (2002) Composite Structures, 58, pp. 83-95Calius, E.P., Springer, G.S., A model of filament-wound thin cylinders (1990) International Journal of Solids and Structures, 26 (3), pp. 271-297Lee, S., Springer, G.S., Filament winding cylinders: III. Selection of the process variables (1990) Journal of Composite Materials, 24, pp. 1344-1366Calius, E.P., Lee, S., Springer, G.S., Filament winding cylinders: II. Validation of the process model (1990) Journal of Composite Materials, 24, pp. 1299-1343Calado, V.M.A., Advani, S.G., (1999) Processing of Continous Fiber Reinforced Composites, pp. 32-107. , EUA: Hanser Publisher. Cap. 2: Thermoset cure kinetics and rheologyAdams, D.F., (2000) Comprehensive Composite Materials: Test Methods, Nondestructive Evaluation, and Smart Materials, pp. 113-148. , Reino Unido: Elsivier Science. Cap. 5.06: Test methods for mechanical propertiesTang, J.M., Lee, W.I., Springer, G.S., Effects of cure pressure on resin flow, voids, and mechanical properties (1987) Journal of Composite Materials, 21, pp. 421-440. , maioChamis, C.C., Simplified composite micromechanics equations for hygral, thermal, and mechanical properties (1984) SAMPE Quarterly, pp. 14-23. , abrilEbube, N.K., Ababio, G.O., Adeyeye, C.M., Preformulation studies and characterization of the physicochemical properties of amorphous polymers using artificial neural networks (2000) International Journal of Pharmaceutics, 196, pp. 27-35Anderson, J.A., (1995) An Introduction to Neural Networks, , EUA: MIT Press, 650 pSwingler, K., (1996) Applying Neural Networks: A Pratical Guide, , Londres: Academic Press, 303 pIlschner, B., Lees, J.K., Dhingra, A.K., (1986) Ullmann's Encyclopedia of Industrial Chemistry. 5.Ed, A7, pp. 384-394. , Alemanha: VCH: Composite MaterialsMano, E.B., (1991) Polímeros como Materiais de Engenharia, , São Paulo: Edgard Blücher, 197 pGuimarães, P.R.B., McGreavy, C., Flow of information through an artificial neural network (1995) Computers and Chemical Engineering, 19, pp. S741-S74