Size‐Exclusion Chromatography in Single and Mixed Eluents: Effects of Sorption of Solvent and Polymer Solutes on Novel TSK‐Gel Super AW Columns

Garcı́a-Lopera, Rosa; Figueruelo, Juan E.; Porcar, Iolanda; Campos, Agustı́n; Abad, Concepción

doi:10.1081/jlc-200041323

Cited by 4 publications

(2 citation statements)

References 32 publications

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Section: Introductionmentioning

confidence: 99%

“…The swelling properties of the packing material will lead to both changes in the porosity and volume of the packing particles. The latter will lead to a change in the void volume of the column, and this will affect the total exclusion. , Swelling of a cross-linked polymer when changing the solvent can be expressed by the difference in the Flory interaction parameter related to the difference in the solubility parameter of the solvent and polymer. The smaller the difference, the more the gel swells within the physical limits of the polymer network.…”

Section: Introductionmentioning

confidence: 99%

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Petroleum Size Exclusion Chromatography: Mechanisms Explaining the NMP Front Peak

Andersen

2019

Energy Fuels

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Size Exclusion Chromatography (SEC) is abundantly used in analysis and fractionation of petroleum fractions despite numerous challenges with the techniques. Changing the eluent type amongst classical solvents in SEC normally leads to smaller changes in the elution profile of asphaltenes. Changing the eluent to N-methyl Pyrrolidone (NMP) however leads to very different chromatographic profiles. Especially the occurrence of a very early eluting peak has been severely debated in the literature without reaching a clear conclusion. NMP has particular solvent properties which target the solubility of aromatic molecules and therefore asphaltenes are only partially soluble. In order to understand the occurrence of the front peak in NMP a systematic study is undertaken by changing eluent solvents and temperature. We discuss the different mechanisms involved in SEC such as phase behavior, gel swelling, pore size, molecular size and unwanted adsorption that are all involved in the chromatographic process. To investigate the phase behavior and effects of reduced solubility the elution in mixtures of heptane and toluene is presented. This leads to an increase adsorption but no indication of larger sized aggregates as could have been Page 1 of 36 ACS Paragon Plus Environment Energy & Fuels expected. Analysis of the difference between NMP, THF and Toluene profiles, indicate that gel swelling and void volume variation are relatively insignificant and cannot explain the early peak. This therefore points at a different mechanism based on fluid dynamic effects known from hydrodynamic chromatography (HDC) of particles, where larger particles travel faster than the average fluid velocity in laminar flow and arrive at the detector before the average void volume. Based on the observations on petroleum systems in NMP we therefore hypothesis that HDC is the driver behind the appearance of the peak in NMP. The insights revealed by the present study show that SEC can be used also to understand changes in solubility in the eluent solvent e.g. caused by alteration in chemistry.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Petroleum Size Exclusion Chromatography: Mechanisms Explaining the NMP Front Peak

Andersen

2019

Energy Fuels

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Treatment of poly(styrene‐co‐methacrylic acid)/poly(4‐vinylpyridine) blends in solution under liquid–liquid phase‐separation conditions. A new method for phase‐separation data attainment from viscosity measurements

Torrens¹,

Soria²,

Monzó³

et al. 2006

J of Applied Polymer Sci

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Phase diagrams are contributed for polymer mixture systems in solution. One polymer has protonacceptor character and the other has growing proton-donor nature, which is reflected in the phase diagrams. Usually, these diagrams are obtained from size-exclusion chromatographic (SEC) measurements. A totally novel application, which is exposed in this report, is the construction of the phase diagram from the viscometric experiments of polymer mixtures. The evaluated binodal or cloud-point isotherms so built agree well with those from SEC. The results indicate an augmentation in the dimensions of donor polymer B, in the presence of acceptor polymer C, intensifying with the concentration of C, which is interpreted as an B-C association growing as the number of hydrogen bonds increases. An increment in the Huggins constant for BC, as the proportion of methacrylic acid in the donor copolymer increases, means an augmentation in the interaction for BC, indicating an extension of compatibility. Viscometric experiments evidence hydrogen bonds, intensifying as greater proportion of donor groups has polymer B, equal to that observed in the phase diagrams.

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Ternary Polymer Solutions with Hydrogen Bonds, 2

Figueruelo

Monzó

Gómez

et al. 2007

Macro Theory & Simulations

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Experimental ternary phase diagrams for ternary systems CHL/PS‐MAA/PVPy with diverse MAA contents have been determined by GPC. The presence of MAA in the copolymers gives rise to specific interactions, by hydrogen bond formation between both polymeric components, so strong that the isotherm for the system with the highest MAA content so far studied, CHL/PS‐MAA(8%)/PVPy, is representative of a complex coacervation situation. By applying the theoretical background deduced by coupling the Flory‐Huggins lattice model to the AET developed for ternary polymeric systems SPP with specific intermolecular interactions (via hydrogen bonds), free energy surfaces for the CHL/PS‐MAA/PVPy systems are constructed. From these plots theoretical ternary phase diagrams are deduced and a fair agreement with those obtained experimentally is observed.

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Size‐Exclusion Chromatography in Single and Mixed Eluents: Effects of Sorption of Solvent and Polymer Solutes on Novel TSK‐Gel Super AW Columns

Cited by 4 publications

References 32 publications

Petroleum Size Exclusion Chromatography: Mechanisms Explaining the NMP Front Peak

Petroleum Size Exclusion Chromatography: Mechanisms Explaining the NMP Front Peak

Treatment of poly(styrene‐co‐methacrylic acid)/poly(4‐vinylpyridine) blends in solution under liquid–liquid phase‐separation conditions. A new method for phase‐separation data attainment from viscosity measurements

Ternary Polymer Solutions with Hydrogen Bonds, 2

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