Optimisation of ambient and high temperature asymmetric flow field-flow fractionation with dual/multi-angle light scattering and infrared/refractive index detection

Otte, Tino; Brüll, Robert; Macko, Tibor; Pasch, Harald; Klein, Thorsten

doi:10.1016/j.chroma.2009.12.014

Cited by 35 publications

(26 citation statements)

References 43 publications

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“…[45] The cut-off limit (lowest mass which was found with 100% recovery) of the present ceramic membrane was determined with narrow PS-standards. [2] It corresponds to %165 kg Á mol À1 for PE in 1,2,4-trichlorobenzene at 145 8C. According to the distribution curves obtained from HT-AF4 for the stabilized sample PE AK01, this PE sample contains only macromolecules with molar masses which are larger than the cut-off limit of the membrane (see Figure 2).…”

Section: Resultsmentioning

confidence: 99%

“…[27,[36][37][38][39][40] Now a new AF4 system is commercially available which is able to operate at temperatures above 130 8C. [2,3,17,41] This makes the advantages of FFF applicable for the characterization of POs. In AF4 the polymer is separated by a cross-flow field according to the diffusion coefficient of the macromolecules or particles.…”

Section: Introductionmentioning

confidence: 99%

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Visualization of Thermo‐Oxidative Degradation of Polyolefins in Solution Using HT‐SEC and HT‐AF4‐MALS

Otte

Pasch

Brüll³

et al. 2011

Macro Chemistry & Physics

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The molar mass distributions of high‐molar‐mass PE and PP were characterized using HT‐AF4 and HT‐SEC in combination with IR and MALS detection. Calculated molar mass distributions, average molar masses and radii of gyration were compared. It was found that HT‐AF4 can detect the real extent of thermo‐oxidative degradation during dissolution. HT‐SEC is affected by shear and thermo‐oxidative degradation while in HT‐AF4 no shear stress exists. As a consequence, the molar mass averages obtained from HT‐SEC are pronouncedly lower as obtained from HT‐AF4. In addition, branched polyolefins cannot be correctly characterized by SEC‐MALS due to abnormal co‐elution effects. HT‐AF4 is therefore the method of choice for studying the thermo‐oxidative degradation of macromolecules with high molar masses. magnified image

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Visualization of Thermo‐Oxidative Degradation of Polyolefins in Solution Using HT‐SEC and HT‐AF4‐MALS

Otte

Pasch

Brüll³

et al. 2011

Macro Chemistry & Physics

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“…Progresses in separation of polymers are of the highest importance to deal with the complexity of the new materials. Research in new separation methods such as field flow fractionation [45] or liquid adsorption chromatography [46] is gaining momentum. SEC has however more to offer than currently exploited.…”

Section: Discussionmentioning

confidence: 99%

Viscosimetric detection in size‐exclusion chromatography (SEC/GPC): The Goldwasser method and beyond

Castignolles

Gaborieau

2010

J of Separation Science

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Size-exclusion chromatography (SEC or GPC) is the most widely used separation method to characterize polymers. The high level of complexity of most polymeric materials necessitates the use of not only concentration-sensitive detection but also structure-sensitive detection. Viscometry is usually used in conjunction with a concentration-sensitive detector and universal calibration to determine molecular weights of polymers. Goldwasser proposed to use a viscometer as a single detector to determine number-average molecular weights, M(n) (ACS Symposium Series, 521, 143). The method is particularly of interest when concentration-sensitive detection is not available, because the sample is isorefractive or not UV-absorbing, or because composition is not constant (copolymers). It has known very little applications so far. It actually does not only allow determining M(n), but also the number hydrodynamic volume distribution. This opens a wider range of applications for the Goldwasser method. Size-exclusion chromatography only yields inaccurate molecular weight distributions for some complex branched polymers. Hydrodynamic volume distributions have then a strong potential for comparative studies owing to their far higher accuracy. Our experimental tests highlight the fact that the method is highly sensitive to noise and careful optimization of the injection concentration is needed, but number distribution can be obtained as well as M(n).

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“…Following the work of Mes et al, a number of detailed studies on the analysis of ultrahigh molar mass polyolefins were conducted by Otte et al [199][200][201][202][203]. It has been demonstrated that HT-AF4 enables one to separate ultrahigh molar mass samples up to a radius of gyration above 1,000 nm without the disturbing effects typical of SEC, namely the shear-degradation of high molar mass structures and the anomalous late co-elution effects.…”

Section: Field Flow Fractionationmentioning

confidence: 99%

Recent Advances in High-Temperature Fractionation of Polyolefins

Pasch

Malik

Macko³

2012

Advances in Polymer Science

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Optimisation of ambient and high temperature asymmetric flow field-flow fractionation with dual/multi-angle light scattering and infrared/refractive index detection

Cited by 35 publications

References 43 publications

Visualization of Thermo‐Oxidative Degradation of Polyolefins in Solution Using HT‐SEC and HT‐AF4‐MALS

Visualization of Thermo‐Oxidative Degradation of Polyolefins in Solution Using HT‐SEC and HT‐AF4‐MALS

Viscosimetric detection in size‐exclusion chromatography (SEC/GPC): The Goldwasser method and beyond

Recent Advances in High-Temperature Fractionation of Polyolefins

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