Effect of polymerization time on the molecular weight distribution of low pressure polyethylene

Taylor, W. C.; Tung, L. H.

doi:10.1002/pol.1963.110010401

Cited by 17 publications

(10 citation statements)

References 10 publications

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“…As illustrated in Figures 6 and 7, a maximum value of Q is also obtained at short reaction times, but the value of Q remains close to the maximum with only a slight decrease with time. Fairly constant values of Q with slight narrowing of the MWD with time are consistent with reported experiments (Natta, 1959;Taylor and Tung, 1963;Crabtree et al, 1973).…”

Section: The Multigrain Modelsupporting

confidence: 91%

Prediction of Molecular Weight Distributions for High-Density Polyolefins

Nagel¹,

Кириллов²,

Ray³

1980

Ind. Eng. Chem. Prod. Res. Dev.

151

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Two models are used to predict the expected molecular weight distribution for polyethylene and polypropylene formed through Ziegler-Natta catalysis. Realistic values of kinetic and physical parameters, taken from experimental studies, are used to provide quantitative results. The simple core model, which neglects catalyst particle breakup, does not allow significant MWD broadening due to diffusion effects. On the other hand, a more realistic multigrain model shows that significant MWD broadening could arise due to intraparticle monomer diffusion limitations.

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Section: The Multigrain Modelsupporting

confidence: 91%

Prediction of Molecular Weight Distributions for High-Density Polyolefins

Nagel¹,

Кириллов²,

Ray³

1980

Ind. Eng. Chem. Prod. Res. Dev.

151

View full text Add to dashboard Cite

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“…In Figure 7(b) and (d), the polydispersity rapidly increases to the peak value, and immediately reduced to its steady state value in about 10 min. Some authors33–35 claimed that for polyethylene obtained with traditional Ziegler‐Natta catalytic systems, the polydispersity is independent of the hydrogen concentration, which is well supported by Figure 7(b). According to the experimental results of Yuan et al,36 however, polypropylene prepared with TiCl 3 · 1/3AlCl 3 (Stauffer type AA)‐Al(C 2 H 5 ) 2 Cl showed slightly higher polydispersity with hydrogen than without hydrogen.…”

Section: Simulation Results and Discussionsupporting

confidence: 56%

Modeling and analysis of a slurry reactor system for heterogeneous olefin polymerization: The effects of hydrogen concentration and initial catalyst size

Yoo

Rhee

2001

J. Appl. Polym. Sci.

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This article deals with the development of a model for the polymerization process using a Ziegler‐Natta catalyst in a slurry reactor system. Employed here is the hierarchical model describing the entire reactor system that is subcategoried by the gas bubble phase, the continuous gas phase, the liquid phase, the solid polymer particle, and the surface of catalyst where chemical reaction occurs. The concept of the multigrain model (MGM) is introduced to describe the growth of polymer particle from the original catalyst particle. We also adopt the concept of multiple active sites to elucidate the broad molecular weight distribution (MWD). The major concern here is the effects of the hydrogen concentration and the size of the initial catalyst on the performance of the polymerization reactor. It is demonstrated that the hydrogen gas can be used for the purpose of controlling not only the molecular weight but the molecular weight distribution (MWD) of the polymer. In addition, the relationship between the molecular weight and the concentration of hydrogen gas is investigated. The size of the initial catalyst is found to exercise a significant influence on the morphology of the resultant polymer particle. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 2480–2493, 2001

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“…In Figure 7(b) and (d), the polydispersity rapidly increases to the peak value, and immediately reduced to its steady state value in about 10 min. Some authors [33][34][35] claimed that for polyethylene obtained with traditional Ziegler-Natta catalytic systems, the polydispersity is independent of the hydrogen concentration, which is well supported by Figure 7(b). According to the experimental results of Yuan et al, 36 however, polypropylene prepared with TiCl 3 ⅐ 1/3AlCl 3 (Stauffer type AA)-Al(C 2 H 5 ) 2 Cl showed slightly higher polydispersity with hydrogen than without hydrogen.…”

Section: Effect Of Hydrogen Concentrationsupporting

confidence: 54%

Modeling and analysis of a slurry reactor system for heterogeneous olefin polymerization: The effects of hydrogen concentration and initial catalyst size

Ha¹,

Yoo²,

Rhee³

2001

J. Appl. Polym. Sci.

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This article deals with the development of a model for the polymerization process using a Ziegler-Natta catalyst in a slurry reactor system. Employed here is the hierarchical model describing the entire reactor system that is subcategoried by the gas bubble phase, the continuous gas phase, the liquid phase, the solid polymer particle, and the surface of catalyst where chemical reaction occurs. The concept of the multigrain model (MGM) is introduced to describe the growth of polymer particle from the original catalyst particle. We also adopt the concept of multiple active sites to elucidate the broad molecular weight distribution (MWD). The major concern here is the effects of the hydrogen concentration and the size of the initial catalyst on the performance of the polymerization reactor. It is demonstrated that the hydrogen gas can be used for the purpose of controlling not only the molecular weight but the molecular weight distribution (MWD) of the polymer. In addition, the relationship between the molecular weight and the concentration of hydrogen gas is investigated. The size of the initial catalyst is found to exercise a significant influence on the morphology of the resultant polymer particle.

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Effect of polymerization time on the molecular weight distribution of low pressure polyethylene

Cited by 17 publications

References 10 publications

Prediction of Molecular Weight Distributions for High-Density Polyolefins

Prediction of Molecular Weight Distributions for High-Density Polyolefins

Modeling and analysis of a slurry reactor system for heterogeneous olefin polymerization: The effects of hydrogen concentration and initial catalyst size

Modeling and analysis of a slurry reactor system for heterogeneous olefin polymerization: The effects of hydrogen concentration and initial catalyst size

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