Recent Advances in Polymer Separations

Lyons, Jim; Poché, Drew S.; Wang, F. C Y; Smith, Patrick B.

doi:10.1002/1521-4095(200012)12:23<1847::aid-adma1847>3.0.co;2-f

Cited by 11 publications

(14 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The stationary phase used was silica, and the mechanism of separation is believed to be precipitation and redissolution driven by the solubility of the copolymer. The resolution of the precipitation/redissolution scheme was low, consistent with prior observations for a precipitation/redissolution scheme …”

Section: Introductionsupporting

confidence: 82%

“…For the past few years, significant research has been conducted at The Dow Chemical Company as well as in other laboratories to develop high temperature gradient liquid chromatography (HT−LC) techniques for fractionating polyolefins according to composition. In the first example of gradient liquid chromatography applied to olefin-based copolymers, poly(ethylene- co -styrene) materials were fractionated by chemical composition at a temperature between 30 and 80 °C . A two-dimensional, temperature rising elution fractionation (TREF)/gel permeation chromatography (GPC) system for cross-fractionation of olefin copolymers was developed .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Development of Comprehensive Two-Dimensional High Temperature Liquid Chromatography × Gel Permeation Chromatography for Characterization of Polyolefins.

et al. 2010

View full text Add to dashboard Cite

This work documents the development of the title system wherein the first dimension is a separation of polyolefins, according to composition, via an adsorption mechanism on a HYPERCARB stationary phase, and the second dimension is a separation of polyolefins on a gel permeation chromatography (GPC) column. Proper optimization of the experimental parameters including high temperature liquid chromatography (HTLC) flow rate, GPC flow rate, GPC column type, and solvent gradient program enabled successful operation of the two-dimensional (2D) system. Two angle light scattering at 90°and 15°and solution infrared absorbance detectors were used for qualitative and quantitative analysis of the 2D data. Apparent composition distribution, apparent molecular weight distribution, and the complete twodimensional (composition Â molecular weight) distribution were obtained for a given polymer. This system is an improvement over a prior two-dimensional system based on temperature rising elution fractionation (TREF)/GPC in that TREF has difficulty separating polyolefins by composition if the polyolefins contain more than approximately 8 mol percent comonomer. Polyolefins synthesized from different catalysts (Metallocene and Ziegler-Natta) showed differences in the molecular weight, composition and number of resolved species in their respective 2D HTLC-GPC chromatograms as a function of catalyst type. Although the polymers studied here were all polyolefins, this approach can also be extended to other polymers.

show abstract

Section: Introductionsupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Development of Comprehensive Two-Dimensional High Temperature Liquid Chromatography × Gel Permeation Chromatography for Characterization of Polyolefins.

et al. 2010

View full text Add to dashboard Cite

show abstract

“…These separations are based on the precipitation and redissolution of the individual polymer fractions. The first example for gradient liquid adsorption chromatography of polymers at elevated temperatures has been reported by Lyons, who fractionated ethylene‐styrene copolymers according to their composition at temperatures between 30 and 80 °C 14. An example for selective adsorption of polyolefins from TCB on zeolithes at 140 °C has been reported by Macko et al15 However, the desorption of the samples was very difficult or even impossible.…”

Section: Introductionmentioning

confidence: 99%

Analysing the Chemical Composition Distribution of Ethylene‐Acrylate Copolymers: Comparison of HT‐HPLC, CRYSTAF and TREF

Albrecht

Brüll

Macko

et al. 2008

Macro Chemistry & Physics

View full text Add to dashboard Cite

HT‐HPLC is an attractive technique to analyse CCD of olefin copolymers and offers the possibility to shorten analysis times compared to fractionation techniques based on crystallisation. We have found that HT‐HPLC enables the selective elution of EMA and EBA copolymers according to their content of the polar co‐monomer. This fractionation could be confirmed by coupling the gradient HPLC system with FT‐IR spectroscopy. The CCDs obtained by this new method were then compared to the results from CRYSTAF. Both methods, HT‐HPLC and CRYSTAF, can discriminate between sets of samples having a narrow or a broad CCD. They can also prove the presence of acrylate‐poor fractions.magnified image

show abstract

“… 1 Therefore, the accurate characterization of these parameters is crucial to understanding the relationship between the structure and properties of complex polymers. 1 , 3 The above-mentioned properties and their distributions are usually determined by various liquid separation techniques; that is, molar mass distribution by size-exclusion chromatography (SEC), chemical composition distribution by liquid adsorption chromatography (LAC), 4 − 10 while end-group functionality and block length distributions in block copolymers are determined by liquid chromatography under critical conditions (LCCC). 11 − 14 LAC and LCCC are also known to be useful techniques for determining various types of microstructures, such as tacticity in polymethacrylates, 15 − 17 and various arrangements of substituents at an olefinic double bond resulting from different polymerization patterns of dienes.…”

Section: Introductionmentioning

confidence: 99%

Influence of Microstructure on the Elution Behavior of Gradient Copolymers in Different Modes of Liquid Interaction Chromatography

Zdovc

Zhao

et al. 2022

Anal. Chem.

View full text Add to dashboard Cite

We studied the influence of microstructure on the chromatographic behavior of gradient copolymers with different gradient strengths and block copolymer with completely segregated blocks by using gradient liquid adsorption chromatography (gLAC) and liquid chromatography at critical conditions (LCCC) for one of the copolymer constituents. The copolymers consist of repeating units of poly(propylene oxide) and poly(propylene phthalate) and have comparable average chemical composition and molar mass, and a narrow molar mass distribution to avoid as much as possible the influence of these parameters on the elution behavior of the copolymers. On both reversed stationary phases, the elution volume of gradient copolymers increases with the increasing strength of the gradient. The results indicate that for both modes of liquid interaction chromatography, it is important to consider the effect of microstructure on the elution behavior of the gradient copolymers in addition to the copolymer chemical composition and molar mass in the case of gLAC and the length of the chromatographically visible copolymer constituent in the case of LCCC.

show abstract

Recent Advances in Polymer Separations

Cited by 11 publications

References 10 publications

Development of Comprehensive Two-Dimensional High Temperature Liquid Chromatography × Gel Permeation Chromatography for Characterization of Polyolefins.

Development of Comprehensive Two-Dimensional High Temperature Liquid Chromatography × Gel Permeation Chromatography for Characterization of Polyolefins.

Analysing the Chemical Composition Distribution of Ethylene‐Acrylate Copolymers: Comparison of HT‐HPLC, CRYSTAF and TREF

Influence of Microstructure on the Elution Behavior of Gradient Copolymers in Different Modes of Liquid Interaction Chromatography

Contact Info

Product

Resources

About