Study of the kinetics, mass transfer, and particle morphology in the production of high‐impact polypropylene

Kittilsen, Pål; McKenna, Timothy F. L.

doi:10.1002/app.1939

Cited by 73 publications

(68 citation statements)

References 9 publications

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“…For this reason, it is necessary to use catalysts loadings of 10-100 mg in the bed depending on catalyst activity and reaction time if we aim to be able to collect enough polymer to perform some analyses of kinetics, molecular weight distribution, and eventually morphology (this latter aspect will be investigated in more details in a future publication). Of course, the difficulty with high catalyst loadings in a packed bed is that, given the highly exothermic nature of the reaction, the poor thermal properties of the continuous gas phase, and the packed-bed configuration of the reactor thermal runaway might occur 44,45 so care will be taken to avoid such problems as presented below.…”

Section: Introductionmentioning

confidence: 99%

Packed‐bed reactor for short time gas phase olefin polymerization: Heat transfer study and reactor optimization

et al. 2011

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A specially conceived packed-bed stopped flow minireactor (3 mL) suitable for short gas phase catalytic reactions has been used to study the start-up of ethylene homopolymerization with a supported metallocene catalyst. Focus has been put on the heat transfer characteristics of the supported catalysts and on understanding the relationship between the initial rate and the relative gas/particle velocities and the influence of particle parameters in the packed bed. We performed a comprehensive study on the influence of various physical parameters on the heat transfer regime at start up conditions. The catalyst activity as well as the polymer morphology is shown to be dependent on heat transfer regime. The knowledge thus obtained is applicable to industrial problems like catalyst injection in fluidized beds and helps preventing experimental artifacts due to overheating in following studies.

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Section: Introductionmentioning

confidence: 99%

Packed‐bed reactor for short time gas phase olefin polymerization: Heat transfer study and reactor optimization

et al. 2011

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“…However, the understanding of the phase morphology of hiPP is far from perfect. Although one can obtain some information about the phase structure of hiPP bulk with the help of cryoultramicrotomy, staining, and surface etching techniques, 2,3,5,9,[13][14][15][16][17][18][19] it is very difficult to gain the structural details of the phase morphology of the material. The corresponding relationship between the complicated chain structure and phase morphology has not been completely established.…”

Section: Introductionmentioning

confidence: 99%

“…2,3,9,[13][14][15] It is generally believed that the dispersed phase in hiPP exhibits a core-shell structure with PE core and EPR shell. [16][17][18][19] This coreshell structure has proven to be efficient for the toughness-rigidity balance of the material.…”

Section: Introductionmentioning

confidence: 99%

The functions of crystallizable ethylene‐propylene copolymers in the formation of multiple phase morphology of high impact polypropylene

Tong¹,

Lan²,

Chen³

et al. 2011

J of Applied Polymer Sci

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ABSTRACT:The functions of crystallizable ethylenepropylene copolymers in the formation of multiple phase morphology of high impact polypropylene (hiPP) were studied by solvent extraction fractionation, transmission electron microscopy (TEM), selected area electron diffraction (SAED), nuclear magnetic resonance ( 13 C-NMR), and selected reblending of different fractions of hiPP. The results indicate that hiPP contains, in addition to polypropylene (PP) and amorphous ethylene-propylene random copolymer (EPR) as well as a small amount of polyethylene (PE), a series of crystallizable ethylene-propylene copolymers. The crystallizable ethylene-propylene copolymers can be further divided into ethylene-propylene segmented copolymer (PE-s-PP) with a short sequence length of PE and PP segments, and ethylene-propylene block copolymer (PE-b-PP) with a long sequence length of PE and PP blocks. PE-s-PP and PE-b-PP participate differently in the formation of multilayered core-shell structure of the dispersed phase in hiPP. PE-s-PP (like PE) constructs inner core, PE-b-PP forms outer shell, while intermediate layer is resulted from EPR. The main reason of the different functions of the crystallizable ethylene-propylene copolymers is due to their different compatibility with the PP matrix.

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“…Inúmeros trabalhos relacionados à modelagem dos mecanismos de transferência de massa e calor dentro da partícula de catalisador já foram publicados com a finalidade de esclarecer o efeito destes fenômenos sobre os processos de polimerização de olefinas [26,28,29,[32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47] . Em trabalhos recentes, McKenna et al [31,48,49] e Eriksson et al [50,51] utilizaram fluido dinâmica computacional para avaliar o efeito dos mecanismos de transferência de massa e calor sobre o processo de polimerização, levando em consideração a influência do tamanho e conformação (relativo a posição e ao contato mútuo) das partículas de catalisador no meio reacional.…”

Section: Morfologia Das Partículas De Polímerounclassified

Uma revisão sobre polimerização de olefinas usando catalisadores Ziegler-Natta heterogêneos

Machado

Pinto

2011

Polímeros

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Resumo: A produção em larga escala de materiais poliméricos de elevado interesse industrial, provenientes da polimerização estereoespecífica de olefinas, tornou-se possível depois do advento dos catalisadores Ziegler-Natta. Classificados genericamente em seis gerações, esses catalisadores apresentam diferentes desempenhos em relação ao grau de especificidade do polímero, à atividade e ao controle de morfologia da partícula, o que propicia o desenvolvimento de resinas poliolefínicas com características e propriedades muito variadas. O objetivo principal desse trabalho é revisar e discutir algumas das questões fundamentais que estão relacionadas com as reações de polimerização de olefinas realizadas com catalisadores heterogêneos. Dá-se ênfase particular aos fatores determinantes para a condução apropriada dos processos industriais, como, por exemplo, a fragmentação controlada do catalisador, o fenômeno de replicação das características estruturais do catalisador e o controle da morfologia da partícula de polímero, a importância da prepolimerização e os efeitos relacionados à transferência de calor e massa durante a reação. Discutem-se também aspectos relacionados à modelagem dos sistemas de polimerização e às técnicas experimentais usadas para o estudo do fenômeno de fragmentação das partículas de catalisador. Palavras-chave: Polimerização de olefinas, catalisadores Ziegler-Natta, morfologia das partículas poliméricas, fragmentação catalítica, modelagem. A Survey on Olefins Polymerization Using Heterogeneous Ziegler-Natta CatalystsAbstract: Large-scale production of polymer materials of high industrial value through stereospecific polymerization of olefins became possible only after the advent of Ziegler-Natta catalysts. Usually grouped into six different generations, these catalysts present distinct activity and allow for production of polymer materials with distinct degrees of stereospecificity, morphology and end-use properties. The main objective of this work is to review and discuss some of the fundamental issues related to olefins polymerization reactions performed with heterogeneous catalysts. Particular emphasis is given to factors that affect the performances of real industrial processes, such as the catalyst fragmentation, the control of the final particle morphology and the morphological replication phenomena, the heat and mass transfer limitations during the polymerization reaction and the prepolymerization stage. Aspects related to the modeling of polymerization reactors and to the experimental study of catalyst fragmentation are also discussed. Keywords: Olefins polymerization, Ziegler-Natta catalysts, polymeric particles morphology, catalyst fragmentation, modeling. IntroduçãoO advento dos catalisadores Ziegler-Natta para polimerizar olefinas como o eteno e o propeno representou um grande marco na história dos processos químicos em geral e dos processos de polimerização em particular. A aplicação destes sistemas catalíticos aos processos de polimerização propiciou o controle de características esté...

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Study of the kinetics, mass transfer, and particle morphology in the production of high‐impact polypropylene

Cited by 73 publications

References 9 publications

Packed‐bed reactor for short time gas phase olefin polymerization: Heat transfer study and reactor optimization

Packed‐bed reactor for short time gas phase olefin polymerization: Heat transfer study and reactor optimization

The functions of crystallizable ethylene‐propylene copolymers in the formation of multiple phase morphology of high impact polypropylene

Uma revisão sobre polimerização de olefinas usando catalisadores Ziegler-Natta heterogêneos

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