Non-exclusion effects in g.p.c.: a review

Audebert, R.

doi:10.1016/0032-3861(79)90025-9

Cited by 23 publications

(9 citation statements)

References 83 publications

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“…As a result, at the same measured M w , the measured R g.z of a slice containing co‐eluted component(s) becomes significantly greater than that of the linear control even if that SEC slice contains just a very small amount of these high MW components. Indeed, a quantitative analysis indicated that in order for these Z‐N polymers to have the elution behavior shown in Figure , it is necessary that SEC slices not only contain normal SEC‐eluting linear and branched polymers, but also the non‐SEC‐eluting components whose molecular weights increase with elution volume …”

Section: Resultsmentioning

confidence: 99%

“…Although well documented, this delayed‐elution phenomenon in SEC is not fully understood . Generally, delayed elution may be a result of one or more of the following mechanisms: macromolecules adsorption onto the column, macromolecules interaction with the column packing material through chain entanglement and macromolecules reptation through the interstitial voids among the packing materials, or the sieving effect . Because TCB is a good solvent for PE at the elution temperature, it is unlikely that the adsorption of Z‐N HDPE onto the column could occur for the elution of PE with TCB at 145 °C .…”

Section: Resultsmentioning

confidence: 99%

“…Indeed, a quantitative analysis [42] indicated that in order for these Z-N polymers to have the elution behavior shown in Figure 4, it is necessary that SEC slices not only contain normal SEC-eluting linear and branched polymers, but also the non-SEC-eluting components whose molecular weights increase with elution volume. [43] Although well documented, this delayedelution phenomenon in SEC is not fully understood. [44][45][46][47][48][49] Generally, delayed elution may be a result of one or more of the following mechanisms: macromolecules adsorption onto the column, macromolecules interaction with the column packing material through chain entanglement and macromolecules reptation through the interstitial voids among the packing materials, or the sieving effect.…”

Section: Sec-mals Of Unfractionated Z-n Homopolymersmentioning

confidence: 99%

“…[44][45][46][47][48][49] Generally, delayed elution may be a result of one or more of the following mechanisms: macromolecules adsorption onto the column, macromolecules interaction with the column packing material through chain entanglement and macromolecules reptation through the interstitial voids among the packing materials, or the sieving effect. [43][44][45][46][47][48][49] Because TCB is a good solvent for PE at the elution temperature, it is unlikely that the adsorption of Z-N HDPE onto the column could occur for the elution of PE with TCB at 145 C. [50] Further, since the largest R g of Z-N molecules at the low elution volumes were found to be less than 100 nm (Figure 4), much smaller than the diameter of the packing materials (20 mm), the sieving effect should not play any important role either. However, it is plausible that the delayed elution could be a result of the interaction between the eluting polymers and the packing material composed of cross-linked polystyrene-divinylbenzene gel.…”

Section: Sec-mals Of Unfractionated Z-n Homopolymersmentioning

confidence: 99%

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Evidences of Long‐Chain Branching in Ziegler‐Natta Polyethylene Homopolymers as Studied via SEC‐MALS and Rheology

Rohlfing

2013

Macromolecular Symposia

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Summary Comprehensive polymer architectural studies were carried out on a group of Ziegler‐Natta (Z‐N) polyethylene homopolymers via size‐exclusion chromatography coupled with multi‐angle light scattering (SEC‐MALS) and rheology. Although Z‐N resins are traditionally viewed as linear polymers, both SEC‐MALS and rheology results strongly indicate that there are topological variations, presumably long‐chain branching (LCB) or possibly hyper‐branches, in this group of supposedly linear Z‐N homopolymers. These Z‐N homopolymers exhibit very complex elution behavior that resulted in anomalous elution profiles in SEC. It appeared that some high molecular weight (MW) and long‐chain branched components followed a non‐size exclusion separation mechanism on SEC columns, co‐eluting with low MW and linear polyethylene components, causing a delayed elution. The possible origin of LCB in these Z‐N polymers is also discussed.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Sec-mals Of Unfractionated Z-n Homopolymersmentioning

confidence: 99%

Section: Sec-mals Of Unfractionated Z-n Homopolymersmentioning

confidence: 99%

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Evidences of Long‐Chain Branching in Ziegler‐Natta Polyethylene Homopolymers as Studied via SEC‐MALS and Rheology

Rohlfing

2013

Macromolecular Symposia

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“…The methods when applied to eq 2 as well as to eq 3 give results for the coefficients of such equations that are valid for samples constituted of monomolecular species independently if they have been obtained from average properties measured on polydisperse samples. Combining eq 2 and 3 to obtain the hydrodynamic volume, we get for a monomolecular species log (MM) = log ( 1+ ) = log K + (1 + )( 0 + AjV + ...) = log K + (1 + ) 0 + (1 + a)A¡V + ... (4) namely log (MM) = C0 + CXV + ... When dealing with polydisperse samples, the experimental intrinsic viscosity of each sample is a weight av-erage of the intrinsic viscosities of the monomolecular species present in it.…”

Section: Resultsmentioning

confidence: 99%

Gel permeation chromatography of poly(N-vinyl-3,6-dibromocarbazole). Universal calibration, nonexclusion effects, and incompatibility

Barrales‐Rienda¹,

Gómez²,

Horta³

et al. 1985

Macromolecules

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Nonexclusion effects in the GPC of poly(N-vinyl-3,6-dibromocarbazole) ) in tetrahydrofuran, at 25 "C, using cross-linked polystyrene (PS) as the gel phase, are analyzed by use of the universal calibration method. The first point in order to determine such nonexclusion effects is to use values for the hydrodynamic volume and the elution volume truly representative of the samples. We show that an adequate set of average magnitudes is the weight-average intrinsic viscosity of the sample, the viscosity-average molecular weight, and the elution volume defined as the viscosity average by means of vv, = log {J3?,(V)[l(P1v] dVJ('/OAL), where H,( V) represents the relative weight of the normalized chromatogram for sample i at elution volume V , a is the exponent in the Mark-Houwink equation for the system under study, and A, is the coefficient of the linear term in the log M vs. V calibration of GPC valid for samples constituted of monomolecular species. The early elution of PVK-3,6-Br2 in THF, as compared with PS standards, can be represented by the equationwhere V , is the retention volume, V,, the interstitial volume, V , the solvent volume within the gel, KD the distribution coefficient for steric exclusion, which is given by KD = -A log ([TIM) + B (A and B are constants), and K is a distribution coefficient for solute-gel interactions. The values of K , found in the present system are gelow unity, and their molecular weight dependence can be represented by -In K, -X,, where X, is the degree of polymerization of the polymer molecule in the mobile phase. In the formulation of Dawkins this corresponds to incompatibility between eluted polymer (2) and gel (3), and -In K,/X, = @3(l + x23), where @3 is the volume fraction of the gel in the stationary phase and ~2 3 the polymer-gel interaction parameter per polymer repeating unit. The compatibility of PVK-3,6-Br2 with PS in THF solution is studied by determining the phase-separation diagram of the ternary system THF (1) + PVK-3,6-Br, (2) + linear PS(3), from which a value of xB at the plait point is determined. The equilibrium distribution of solute polymer (2) between the mobile phase and the gel is treated thermodynamically as a problem in preferential sorption in a ternary system (selective adsorption or desorption of 2 by 3 from the 1 + 2 solution). The result of this thermodynamic treatment is -In K,/X, = b3(l + g23 -g12 -g13), which is similar to the one given by Dawkins, but now it includes the additional contribution of the polymersolvent and gel-solvent interaction parameters g,, and g13. These g,'s and the x,,'s defined on the basis of chemical potential are connected through xi, = g,, -(1 -@,)(dg,,/d@,). The value of gl, + g13 can be of the order of unity so that (1 -g12 -g13) can approximately cancel. This expression gives thus the conditions under which K, can be unity or differ from unity depending on the balance of the interaction parameters. IntroductionAs has been recognized for a long time, steric exclusion from a theoretical point of view is the only...

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Polymer retention mechanisms in GPC on active gels, 3. Poly(dimethylsiloxane) and poly(methyl methacrylate)

Figueruelo¹,

Soria²,

Campos³

1981

Makromol. Chem.

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Elution curves on spherosil gels in pure and mixed eluents of poly(dimethylsiloxane), PDMS, and poly(methy1 methacrylate), PMMA, as well as those of polystyrene, PS, just for comparison, have been determined. In a general way, PDMS elution volumes fit to those of PS, whereas PMMA elution curves shift to higher retention volumes. The differences in retention volumes between the different polymeric solutes have been interpreted in terms of differences in polymer-gel and polymer-solvent interactions. Hydrogen-bonding seems to be the main contribution to solute-substrate interactions.

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Non-exclusion effects in g.p.c.: a review

Cited by 23 publications

References 83 publications

Evidences of Long‐Chain Branching in Ziegler‐Natta Polyethylene Homopolymers as Studied via SEC‐MALS and Rheology

Evidences of Long‐Chain Branching in Ziegler‐Natta Polyethylene Homopolymers as Studied via SEC‐MALS and Rheology

Gel permeation chromatography of poly(N-vinyl-3,6-dibromocarbazole). Universal calibration, nonexclusion effects, and incompatibility

Polymer retention mechanisms in GPC on active gels, 3. Poly(dimethylsiloxane) and poly(methyl methacrylate)

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