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Dynamic Modeling of a Moving-Packed-Bed Reactor for the Solid-State Polymerization of Bisphenol-A Polycarbonate / Yuesheng Ye in Industrial & engineering chemistry research, Vol. 47 N°10 (Mai 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 N°10 (Mai 2008) . - p. 3687-3699 Titre : Dynamic Modeling of a Moving-Packed-Bed Reactor for the Solid-State Polymerization of Bisphenol-A Polycarbonate Type de document : texte imprimé Auteurs : Yuesheng Ye, Auteur ; Kyu Yong Choi, Auteur Année de publication : 2008 Article en page(s) : p. 3687-3699 Langues : Anglais (eng) Mots-clés : Dynamic  Modeling  ;  Polymerization  ;  Polycarbonate Résumé : A dynamic process model has been developed for a continuous solid-state step-growth polymerization of bisphenol-A polycarbonate in a moving-packed-bed reactor. In this process, the molecular weight of polycarbonate prepolymer particles is increased as they move downward in a vertical reactor. A heated purge gas is supplied to the bottom of the reactor and flows upward at a high flow rate to remove volatile condensates from the polymer particles and provide thermal energy for the solid-state polymerization. A macroscopic reactor model and a polymer particle model are combined and solved together to calculate the reactor temperature profiles and the polymer-molecular-weight properties. The effects of reactor design and operation parameters on the performance of the solid-state polymerization reactor are analyzed through model simulations. It is shown that a large-scale moving-packed-bed reactor can have a significant temperature nonuniformity in the reactor, particularly during the startup operation, affecting the uniformity of the molecular weight of the polymer in the product. En ligne : https://pubs.acs.org/doi/abs/10.1021/ie071078s [article] Dynamic Modeling of a Moving-Packed-Bed Reactor for the Solid-State Polymerization of Bisphenol-A Polycarbonate [texte imprimé] / Yuesheng Ye, Auteur ; Kyu Yong Choi, Auteur . - 2008 . - p. 3687-3699. Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 N°10 (Mai 2008) . - p. 3687-3699 Mots-clés : Dynamic  Modeling  ;  Polymerization  ;  Polycarbonate Résumé : A dynamic process model has been developed for a continuous solid-state step-growth polymerization of bisphenol-A polycarbonate in a moving-packed-bed reactor. In this process, the molecular weight of polycarbonate prepolymer particles is increased as they move downward in a vertical reactor. A heated purge gas is supplied to the bottom of the reactor and flows upward at a high flow rate to remove volatile condensates from the polymer particles and provide thermal energy for the solid-state polymerization. A macroscopic reactor model and a polymer particle model are combined and solved together to calculate the reactor temperature profiles and the polymer-molecular-weight properties. The effects of reactor design and operation parameters on the performance of the solid-state polymerization reactor are analyzed through model simulations. It is shown that a large-scale moving-packed-bed reactor can have a significant temperature nonuniformity in the reactor, particularly during the startup operation, affecting the uniformity of the molecular weight of the polymer in the product. En ligne : https://pubs.acs.org/doi/abs/10.1021/ie071078s

Modeling and control of sequence length distribution for controlled radical (RAFT) copolymerization / Yuesheng Ye in Industrial & engineering chemistry research, Vol. 48 N° 24 (Décembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10827–10839 Titre : Modeling and control of sequence length distribution for controlled radical (RAFT) copolymerization Type de document : texte imprimé Auteurs : Yuesheng Ye, Auteur ; F. Joseph Schork, Auteur Année de publication : 2010 Article en page(s) : pp. 10827–10839 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Modeling--Control--Sequence--Length--Distribution--Controlled--Radical--(RAFT)--Copolymerization Résumé : Controlled/living radical polymerization (CRP) allows a high degree of control over polymeric molecular architecture with narrow molecular weight distributions and desired polymer properties. Although the control of copolymer composition for RAFT copolymerization systems in a semibatch reactor has been studied, the control of sequence length receives little attention. In this work, using moment equations, a chain model and a sequence model were developed to describe both chain and sequence properties such as chain and sequence lengths and their distributions, for RAFT copolymerization in semibatch operations. It is seen that a copolymer with constant composition or linear gradient composition can be obtained through an optimized feeding policy. With the sequence model, it was possible to show the sequence length and distributions while controlling constant composition or linear gradient composition. More importantly, it was demonstrated that sequence length distribution can be designed and controlled using the sequence model. The sequence model may be used as a theoretical tool to understand the importance of sequence length and distributions in CRP. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901032y [article] Modeling and control of sequence length distribution for controlled radical (RAFT) copolymerization [texte imprimé] / Yuesheng Ye, Auteur ; F. Joseph Schork, Auteur . - 2010 . - pp. 10827–10839. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10827–10839 Mots-clés : Modeling--Control--Sequence--Length--Distribution--Controlled--Radical--(RAFT)--Copolymerization Résumé : Controlled/living radical polymerization (CRP) allows a high degree of control over polymeric molecular architecture with narrow molecular weight distributions and desired polymer properties. Although the control of copolymer composition for RAFT copolymerization systems in a semibatch reactor has been studied, the control of sequence length receives little attention. In this work, using moment equations, a chain model and a sequence model were developed to describe both chain and sequence properties such as chain and sequence lengths and their distributions, for RAFT copolymerization in semibatch operations. It is seen that a copolymer with constant composition or linear gradient composition can be obtained through an optimized feeding policy. With the sequence model, it was possible to show the sequence length and distributions while controlling constant composition or linear gradient composition. More importantly, it was demonstrated that sequence length distribution can be designed and controlled using the sequence model. The sequence model may be used as a theoretical tool to understand the importance of sequence length and distributions in CRP. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901032y

Modeling and control of sequence length distribution for controlled radical (RAFT) copolymerization / Yuesheng Ye in Industrial & engineering chemistry research, Vol. 48 N° 24 (Décembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10827–10839 Titre : Modeling and control of sequence length distribution for controlled radical (RAFT) copolymerization Type de document : texte imprimé Auteurs : Yuesheng Ye, Auteur ; F. Joseph Schork, Auteur Année de publication : 2010 Article en page(s) : pp. 10827–10839 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Controlled/living  radical  polymerization  RAFT  copolymerization  systems Résumé : Controlled/living radical polymerization (CRP) allows a high degree of control over polymeric molecular architecture with narrow molecular weight distributions and desired polymer properties. Although the control of copolymer composition for RAFT copolymerization systems in a semibatch reactor has been studied, the control of sequence length receives little attention. In this work, using moment equations, a chain model and a sequence model were developed to describe both chain and sequence properties such as chain and sequence lengths and their distributions, for RAFT copolymerization in semibatch operations. It is seen that a copolymer with constant composition or linear gradient composition can be obtained through an optimized feeding policy. With the sequence model, it was possible to show the sequence length and distributions while controlling constant composition or linear gradient composition. More importantly, it was demonstrated that sequence length distribution can be designed and controlled using the sequence model. The sequence model may be used as a theoretical tool to understand the importance of sequence length and distributions in CRP. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901032y [article] Modeling and control of sequence length distribution for controlled radical (RAFT) copolymerization [texte imprimé] / Yuesheng Ye, Auteur ; F. Joseph Schork, Auteur . - 2010 . - pp. 10827–10839. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10827–10839 Mots-clés : Controlled/living  radical  polymerization  RAFT  copolymerization  systems Résumé : Controlled/living radical polymerization (CRP) allows a high degree of control over polymeric molecular architecture with narrow molecular weight distributions and desired polymer properties. Although the control of copolymer composition for RAFT copolymerization systems in a semibatch reactor has been studied, the control of sequence length receives little attention. In this work, using moment equations, a chain model and a sequence model were developed to describe both chain and sequence properties such as chain and sequence lengths and their distributions, for RAFT copolymerization in semibatch operations. It is seen that a copolymer with constant composition or linear gradient composition can be obtained through an optimized feeding policy. With the sequence model, it was possible to show the sequence length and distributions while controlling constant composition or linear gradient composition. More importantly, it was demonstrated that sequence length distribution can be designed and controlled using the sequence model. The sequence model may be used as a theoretical tool to understand the importance of sequence length and distributions in CRP. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901032y

Reduction of bisphenol A residue in polycarbonates in a two-stage step-growth polymerization process / Yuesheng Ye in Industrial & engineering chemistry research, Vol. 48 N° 9 (Mai 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 9 (Mai 2009) . - pp. 4274–4282 Titre : Reduction of bisphenol A residue in polycarbonates in a two-stage step-growth polymerization process Type de document : texte imprimé Auteurs : Yuesheng Ye, Auteur ; Kyu Yong Choi, Auteur Année de publication : 2009 Article en page(s) : pp. 4274–4282 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Polycondensation  process  Bisphenol  A  Bisphenol  A  polycarbonate Résumé : A theoretical modeling and simulation study is presented for the design of operational policies for a two-stage polycondensation process to achieve a significant reduction of bisphenol A (BPA) residue in high molecular weight bisphenol A polycarbonate (BAPC). In the first stage, low molecular weight polycarbonate prepolymers are prepared in a semibatch melt transesterification reactor under reduced pressure, and in the second stage, a solid-state polymerization is used to further increase the polymer molecular weight and to reduce the BPA residue. The residual BPA concentration in the final polymer can be significantly reduced by employing an optimally determined excess amount of diphenyl carbonate (DPC) in the transesterification stage. However, there is a narrow window of operating conditions that will satisfy the multiple process requirements of the lowest BPA concentration, high molecular weight, and economically feasible short reaction time. The proposed method can also be applied to optimally blending prepolymers of different reactive end group concentrations for the subsequent solid-state polymerization to reduce the BPA content and to obtain high molecular weight. The proposed methods are illustrated through model simulations. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8014318 [article] Reduction of bisphenol A residue in polycarbonates in a two-stage step-growth polymerization process [texte imprimé] / Yuesheng Ye, Auteur ; Kyu Yong Choi, Auteur . - 2009 . - pp. 4274–4282. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 9 (Mai 2009) . - pp. 4274–4282 Mots-clés : Polycondensation  process  Bisphenol  A  Bisphenol  A  polycarbonate Résumé : A theoretical modeling and simulation study is presented for the design of operational policies for a two-stage polycondensation process to achieve a significant reduction of bisphenol A (BPA) residue in high molecular weight bisphenol A polycarbonate (BAPC). In the first stage, low molecular weight polycarbonate prepolymers are prepared in a semibatch melt transesterification reactor under reduced pressure, and in the second stage, a solid-state polymerization is used to further increase the polymer molecular weight and to reduce the BPA residue. The residual BPA concentration in the final polymer can be significantly reduced by employing an optimally determined excess amount of diphenyl carbonate (DPC) in the transesterification stage. However, there is a narrow window of operating conditions that will satisfy the multiple process requirements of the lowest BPA concentration, high molecular weight, and economically feasible short reaction time. The proposed method can also be applied to optimally blending prepolymers of different reactive end group concentrations for the subsequent solid-state polymerization to reduce the BPA content and to obtain high molecular weight. The proposed methods are illustrated through model simulations. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8014318