Determination of the infinite dilution diffusion and activity coefficients of alkanes in polypropylene by inverse gas chromatography

Zhao, Changwei; Li, Jiding; Zeng, Chuyi

doi:10.1002/app.23658

Cited by 9 publications

(8 citation statements)

References 14 publications

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“…The diffusion coefficient ( D ∞ ) can be calculated by using the van Deemter plot according to Eq. :

D^{\infty} = \frac{8 d_{p}^{2} k}{π C {(1 + k)}^{2}} in m^{2} / normals,

where d p is the particle diameter, k the partition ratio equal to the time difference between the probe ( t r ) and the inert marker ( t 0 ), divided by the retention time of the inert marker ( t 0 ) and C is the slope from the van Deemter plot C ‐term. The C ‐term corresponds to the mass transfer processes during sorption and desorption .…”

Section: Resultsmentioning

confidence: 99%

“…From this, thermodynamic data, the sorption enthalpy (ΔH s ), molar free energy of sorption (ΔG s ), entropy of sorption (ΔS s ), and the partitioning constant between solid and gas phase (K d ) can be calculated [11,16]. Furthermore, IGC allows for the determination of kinetic data such as diffusion (D ∞ ) [17] and dispersion coefficients (D*) [18]. The multiplication of the diffusion coefficient with the partitioning constant yields the probes apparent permeability (P app ) [19][20][21].…”

Section: F I G U R E 1 Setup Of the Itex Needle As Igc Columnmentioning

confidence: 99%

“…The diffusion coefficient (D ∞ ) can be calculated by using the van Deemter plot according to Eq. (5) [17]:…”

Section: Determination Of the Diffusion Coefficient Dispersion Coeffmentioning

confidence: 99%

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Sorbent material characterization using in‐tube extraction needles as inverse gas chromatography column

Barajas

Jochmann

Hüffer

et al. 2017

J of Separation Science

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In-tube extraction is a full automated enrichment technique that consists of a stainless-steel needle, packed with sorbent material for the extraction of volatile and semivolatile compounds. In principle, all particulate sorbents used for enrichment in air or headspace analysis can be used. However, the selection of the sorbents is merely based on empirical considerations rather than on experimental data, which is caused by a lack of knowledge about the relevant physicochemical properties of the sorbent. Especially, the knowledge of hydrostatic, advective, diffusive, and dispersion mechanisms in addition to sorption enthalpies are important for combined transport and sorption models. To provide these missing parameters, we developed and evaluated a method in which an ordinary in-tube extraction needle was employed directly as column for sorbent characterization by inverse gas chromatography. As probe compounds, benzene, ethyl acetate, and 3-methyl-1-butanol were used to determine thermodynamic parameters such as sorption enthalpy, partitioning constant between the solid and gas phase, and kinetic parameters such as the diffusion coefficient, dispersion coefficient, and apparent permeability, exemplarily. As sorbent, three commercially available phases were characterized to demonstrate the applicability of the method.

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“…The diffusion coefficient ( D ∞ ) can be calculated by using the van Deemter plot according to Eq. :

D^{\infty} = \frac{8 d_{p}^{2} k}{π C {(1 + k)}^{2}} in m^{2} / normals,

Section: Resultsmentioning

confidence: 99%

Section: F I G U R E 1 Setup Of the Itex Needle As Igc Columnmentioning

confidence: 99%

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Sorbent material characterization using in‐tube extraction needles as inverse gas chromatography column

Barajas

Jochmann

Hüffer

et al. 2017

J of Separation Science

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“…In order to evaluate the effect of temperature on the diffusion behaviour of waterproof sealants, a function, which can describe the relationship between the temperature and the diffusion coefficient, needs to be investigated. The Arrhenius equation describes the relationship between the reaction rate and temperature, which can also characterize the relationship between temperature and diffusion coefficient based on current research [34]. Arrhenius equation is expressed by Equation (8),…”

Section: Relationship Between the Diffusion Coefficient And Temperamentioning

confidence: 99%

Molecule diffusion behaviours of waterproof sealants into silicone rubber insulation for submarine cable joint based on molecular dynamics simulations

Zhang¹,

Wang

et al. 2020

High Voltage

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The repair joints of high‐voltage cables play a significant role in the urgent cable maintenance, by recovering cable conductor, insulation, shielding layer and waterproof layer especially for submarine cables. However, the molecule diffusion and permeation processes from waterproof sealant into the cable joint insulation occur, leading to the insulation ageing and deterioration. In this article, the molecule diffusion behaviours of six typical molecules from the asphalt‐based and polyurethane‐based waterproof sealants into silicone rubber insulation are investigated. The results show that the order of diffusion coefficients is as follows, phenanthrene > fluoranthene > pyrene > benzo [k] fluoranthene > indeno [1,2,3‐cd] pyrene > polyurethane (PU). The relative molecular mass and binding energy are pivotal factors affecting the diffusion behaviour, while there is a linear relationship between the logarithm of the diffusion coefficient and the ratio of binding energy to relative molecular mass. Besides, the rising ambient temperature increases the fraction of free volume of silicone rubber and decreases the binding energy, thus resulting in a higher diffusion coefficient and an enhanced permeation process of the asphalt‐based sealant. In summary, the PU‐based waterproof sealant, with a much lower permeability than the asphalt‐based material, has a potential application in the waterproof layer for high‐voltage submarine cable repair joints.

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“…Meanwhile, it may be noticed that, for PiBA, the CH 3 (CH)CH 2 CH 3 group in its repeating Figure 3. Experimental data 17,19 and predictions for infinite dilution diffusion coefficients of hexane in PVAc and PP.…”

Section: Prediction Of Solvent Self-diffusion Coefficientmentioning

confidence: 99%

A Group Contribution-Based Model to Predict Organic Solvent Diffusivities in Amorphous Rubbery Polymers

Wang

Yang

2007

Polym J

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ABSTRACT:A modified free-volume model was developed to predict solvent diffusion coefficients in amorphous rubbery polymers, with the introduction of the Sanchez-Lacombe equation-of-state (EOS) into the free-volume theory. The characteristic parameters of the EOS are the only introduced parameters, and they can be determined with the knowledge of polymer structural units. Since all of the parameters with respect to the polymer can be determined by the group contribution method, this model provides feasibility to correlate the solvent diffusivities with polymer structures, without the knowledge of any diffusion or viscoelastic data. The calculations of infinite dilution diffusion coefficients and solvent self-diffusion coefficients for seven kinds of organic solvents in seven kinds of polymers were generally consistent with the published experimental results. The diffusion phenomena of organic solvents in polymers play an important role in many industrial processes, such as polymer processing and drying of solvent coated polymer films. More particularly, estimation of solvent diffusivities is one of the key factors to develop a design methodology for polymeric membrane based organic mixture separation, such as pervaporation (PV) and vapor permeation (VP).During the past 50 years, the free-volume theory, especially the one developed by Vrentas and Duda, has served as the main basis for the description of transport properties in polymer solutions.1-10 The distinct characteristic of this representative model is that there are no adjustable constants and most parameters can be obtained from pure component data. According to this model, the free volume is the controlling factor for solvent jumping in an amorphous rubbery polymer, and the free-volume parameters of some common solvents and polymers have been published, using the viscosity-temperature data.4,10 However, due to the lack of viscosity data in the literature, the available free-volume parameters are still insufficient especially for polymers, the physical properties of which are more complicated and uncertain than those of solvents. In recent papers, 11,12 equations-of-state (EOSs) have been introduced to estimate the free volume of polymer, and the complicated process of measuring polymer viscoelasticity has been avoided. However, it still suffers from the limitation that the characteristic parameters of the polymers summarized in the literature are also limited, which obviously restricts the application of the diffusion model. In addition, predictions of infinite dilution diffusion coefficient, which can provide convincing examination of the reliability of the modified model, are not given. In order to remove these shortcomings, the present work will predict the solvent diffusivities in polymers from group contribution method, using the chemical formula of polymer structural units as input. EXPERIMENTALAccording to the free-volume model established by Vrentas and Duda, 4,10 for an amorphous rubbery polymer-solvent system, the solvent self-diffusion coeffic...

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Determination of the infinite dilution diffusion and activity coefficients of alkanes in polypropylene by inverse gas chromatography

Cited by 9 publications

References 14 publications

Sorbent material characterization using in‐tube extraction needles as inverse gas chromatography column

Sorbent material characterization using in‐tube extraction needles as inverse gas chromatography column

Molecule diffusion behaviours of waterproof sealants into silicone rubber insulation for submarine cable joint based on molecular dynamics simulations

A Group Contribution-Based Model to Predict Organic Solvent Diffusivities in Amorphous Rubbery Polymers

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