Solubilities of ethylene and other organic solutes in liquid, low‐density polyethylene in the region 124° to 300°C

Maloney, Dennis P.; Prausnitz, John M.

doi:10.1002/aic.690220108

Cited by 67 publications

(41 citation statements)

References 24 publications

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“…Similar behavior has been observed experimentally for the case of various nalkanes and R-olefins in low-density polyethylene. 34 No experimental data are available in the literature for PDMSM at this elevated temperature.…”

Section: Free Volume Analysis Of Pdmsmmentioning

confidence: 96%

Molecular Dynamics Simulation of Structure and Thermodynamic Properties of Poly(dimethylsilamethylene) and Hydrocarbon Solubility Therein: Toward the Development of Novel Membrane Materials for Hydrocarbon Separation

et al. 2004

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Molecular dynamics simulation is used to model the structure and thermodynamic properties of a novel rubbery polymer with promising membrane properties for hydrocarbon separation. A realistic united atom force field is developed based on extensive density functional theory quantum mechanics calculations for a model dimer and volumetric data at various temperatures and pressures. Both a constant bond length and a flexible bond length model are examined. Well-equilibrated structures of the polymer melt at various conditions are used to evaluate numerous thermodynamic properties, such as the isothermal compressibility, thermal expansion coefficient, and cohesive energy density, and structural properties, including intra-and intermolecular distribution functions and the static structure factor. The microscopic structure of the free volume of the polymer matrix and its evolution with time affects the diffusion of penetrant molecules considerably; they are calculated accurately using the Greenfield and Theodorou geometric analysis. The solubilities of various n-alkanes from methane to n-hexane at 300 and 400 K are calculated using the Widom test particle insertion technique. In all cases, simulation results are in good agreement with literature experimental data for the volumetric properties of the polymer melt and the solubility coefficients of n-alkanes in the polymer. In a forthcoming publication, the transport properties of these systems and the underlying molecular mechanisms will be examined.

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Section: Free Volume Analysis Of Pdmsmmentioning

confidence: 96%

Molecular Dynamics Simulation of Structure and Thermodynamic Properties of Poly(dimethylsilamethylene) and Hydrocarbon Solubility Therein: Toward the Development of Novel Membrane Materials for Hydrocarbon Separation

et al. 2004

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“…Following the work of Maloney and Prausnitz, 34 the polymer phase fugacity of solute i is written as…”

Section: Acknowledgmentsmentioning

confidence: 99%

Simulation of the effects of chain architecture on the sorption of ethylene in polyethylene

Banaszak

Faller

Pablo

2004

The Journal of Chemical Physics

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An osmotic ensemble hyperparallel tempering technique has been developed to study the solubility of ethylene in amorphous linear low-density polyethylene of different chain architectures. The NERD united-atom force field ͑Nath, Escobedo, and de Pablo revised united-atom force field͒ ͓Nath et al., J. Chem. Phys. 108, 9905 ͑1998͒; Mol. Phys. 98, 231 ͑2000͒; J. Chem. Phys. 114, 3612 ͑2001͔͒ is used in all simulations. We have investigated the effect of polyethylene chain length and branching on ethylene solubility. In this study, we have considered short-chain branching of amorphous linear low-density ethylene-1-hexene copolymers under typical polymerization reactor conditions. It is observed that, in the polymer, ethylene prefers to reside in the vicinity of polymer chain ends. This clustering causes a decrease in ethylene solubility with polymer chain length. When short-chain branches are introduced to a linear polymer chain, however, the chain-end clustering effect is counteracted by a higher density, thereby leading to an ethylene solubility almost identical to that in the linear polymer.

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“…The theoretical foundation for the correlation between the zero‐pressure weight‐fraction‐based Henry's constant $(H_{{\rm 12}}^0 )$ and specific retention volume ($V_{\rm g}^0$ ) is well established in the IGC literature 4. Here, we only present key expressions used to calculate $H_{{\rm 12}}^0$ .…”

Section: Experimental Partmentioning

confidence: 99%

“…Measurements were made on low‐density polyethylene (LDPE) to check the reliability of the adopted approach. This is simply because data for LDPE over the temperature range of interest (170 to 230 °C) are available in the open literature 3–10…”

Section: Introductionmentioning

confidence: 99%

Differences between Ziegler–Natta and Single‐Site Linear Low‐Density Polyethylenes as Characterized by Inverse Gas Chromatography

Zhao

Choi

2004

Macromol. Rapid Commun.

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Summary: Zero‐pressure weight‐fraction‐based Henry's constants $(H_{{\rm 12}}^0 )$ of two alkanes, two alkenes, and benzene in Ziegler–Natta (ZN) and single‐site (ss) linear low‐density polyethylenes (LLDPE) with different average branch contents, molecular‐weight averages ($\overline M _{\rm n}$ and $\overline M _{\rm w}$), and polydispersity indices (PDI) were measured in the temperature range of 170 to 230 °C using the technique of inverse gas chromatography. For both types of LLDPEs, the measured $H_{{\rm 12}}^0$ was insensitive to molecular weight and PDI. However, the branch content dependence differed significantly. In particular, ZN‐LLDPE exhibited a strong branch content dependence on $H_{{\rm 12}}^0$ while ss‐LLDPE did not. In fact, depending on the temperature and solvent used, $H_{{\rm 12}}^0$ of ZN‐LLDPE could drop as much as 21% with an increase in an average branch content from 13 to 35 branches per 1 000 backbone carbons, while the differences of $H_{{\rm 12}}^0$ between ss‐LLDPEs with comparable differences in branch content were well within experimental uncertainties (5%). This observation is also supported by the fact that comparable ZN‐ and ss‐LLDPEs exhibited larger differences in $H_{{\rm 12}}^0$ at higher average branch contents. The above findings strongly suggested that the liquid morphologies of ZN‐ and ss‐LLDPEs differ considerably. In particular, the local chain conformation and free volume characteristics (i.e., the size distribution and/or spatial distribution of the free volume holes) of them are rather different. Such differences become more pronounced at higher temperatures.

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Solubilities of ethylene and other organic solutes in liquid, low‐density polyethylene in the region 124° to 300°C

Cited by 67 publications

References 24 publications

Molecular Dynamics Simulation of Structure and Thermodynamic Properties of Poly(dimethylsilamethylene) and Hydrocarbon Solubility Therein: Toward the Development of Novel Membrane Materials for Hydrocarbon Separation

Molecular Dynamics Simulation of Structure and Thermodynamic Properties of Poly(dimethylsilamethylene) and Hydrocarbon Solubility Therein: Toward the Development of Novel Membrane Materials for Hydrocarbon Separation

Simulation of the effects of chain architecture on the sorption of ethylene in polyethylene

Differences between Ziegler–Natta and Single‐Site Linear Low‐Density Polyethylenes as Characterized by Inverse Gas Chromatography

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