High-temperature gradient HPLC for the separation of polyethylene–polypropylene blends

Heinz, Lars-Christian; Pasch, Harald

doi:10.1016/j.polymer.2005.11.001

Cited by 61 publications

(52 citation statements)

References 36 publications

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“…For comparison, a separation of PE from PP with molar mass below about 20 kg/mol was not possible using precipitation-redissolution chromatography with EGMBE as the mobile phase. 36,37 We note that oligomers of PE and PP with smaller molar mass evaporate at 260 C in the ELSD and therefore do not yield a detector response.…”

Section: Resultsmentioning

confidence: 92%

“…The group of Prof. H. Pasch (present address: University of Stellenbosch, Stellenbosch, South Africa) in Darmstadt has recently published the first HPLC procedures for the separation of PE and PP. [36][37][38][39][40][41][42][43] PE or PP were selectively adsorbed in the zeolites [40][41][42][43] or HPLC separation has been based on selective precipitation of PE. 36,38 Lehtinen und Paukerri 44 found that ethylene glycol monobutyl ether (EGMBE) dissolves isotactic polypropylene (iPP) but not linear PE.…”

Section: Introductionmentioning

confidence: 99%

“…1,2,4-trichlorobenzene (TCB). 36 Using this approach it was for the first time possible to separate ethylene-propylene (EP) copolymers according to their chemical composition. 45,46 However, there is still a significant influence of the molar mass on the separation, which makes it unpractical for routine analysis.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of ethylene‐propylene copolymers with high‐temperature gradient adsorption liquid chromatography and CRYSTAF

Macko¹,

Brüll²,

Wang

et al. 2011

J of Applied Polymer Sci

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Blends of linear polyethylene (PE) and isotactic polypropylene (iPP) with different average molar masses and a series of ethylene-propylene (EP) copolymers with different chemical composition as well as blends of PE, Ipp, and EP copolymers were separated using a carbon-column packing (HypercarbV R ) and gradients of 1-decanol or 2-ethyl-1-hexanol ! 1,2,4-trichlorobenzene (TCB). The separation is based on full adsorption of linear PE on the carbon sorbent at temperature 160 C. However, iPP is not adsorbed and elutes in size exclusion mode. The random EP copolymers have been adsorbed in the column packing and separated according to their average chemical composition after application of the gradient starting with alcohol and ending with pure TCB. The elution volumes of the copolymers depended linearly on the average concentration of ethylene in the copolymers. The HPLC elution profiles were correlated with the CRYSTAF elution profiles. In contrast to CRYSTAF, fully amorphous polyolefin samples were separated with the high-temperature adsorption liquid chromatography.

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Section: Resultsmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

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Characterization of ethylene‐propylene copolymers with high‐temperature gradient adsorption liquid chromatography and CRYSTAF

Macko¹,

Brüll²,

Wang

et al. 2011

J of Applied Polymer Sci

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“…21 To highlight this new advance, results using the silica column system designed by Heinz et al are compared against new data generated using the graphitic carbon column. 18 Previous results with a graphitic carbon column from Macko et al are also compared to the current work. 19,20 …”

Section: Introductionmentioning

confidence: 75%

Separation of polyolefins based on comonomer content using high‐temperature gradient adsorption liquid chromatography with a graphitic carbon column

Miller

deGroot

Lyons

et al. 2011

J of Applied Polymer Sci

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This report describes the application of a recently developed polyolefin characterization tool based upon gradient adsorption high-temperature liquid chromatography (HT-LC) using a graphitic carbon stationary phase to polyolefin homopolymer and previously unreported copolymer systems. Polyolefin-based materials find utility in a broad range of applications and are differentiated by parameters such as molecular weight and comonomer content. Polymer comonomer distribution is commonly determined by crystallinity-based separations (ATREF, CRYSTAF). These techniques, however, are time consuming. In addition, some semicrystalline polymers undergo cocrystallization, impacting the techniques' universal utility. Adsorption-based HT-LC can ideally overcome the limitations of crystallinity-based separations, shedding new light on the composition of randomly-polymerized polyolefins. In this report the basic separation capability of the adsorption HT-LC technique, using a graphitic carbon column, is demonstrated for poly (ethylene-co-octene) and poly(ethylene-co-propylene) systems and compared with select precipitation/redissolution HT-LC and ATREF results. Select results in this paper are also compared and contrasted to other recent publications on similar separations of polyolefins.

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“…Lehtinen and Paukkeri found that ethylene glycol monobutyl ether (EGMBE) is a good solvent for isotactic PP but a nonsolvent for linear PE [62]. This observation forms the basis for the HT HPLC separation of isotactic PP from linear PE using EGMBE as eluent [63,64]. The column used by Macko et al…”

Section: Chromatographic System Based On the Precipitation-dissolutiomentioning

confidence: 99%

A review on the development of liquid chromatography systems for polyolefins

Macko¹,

Brüll²,

Zhu

et al. 2010

J of Separation Science

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Polyolefins are the most widely produced synthetic polymer commodity and are found in countless applications ranging from bottles, packaging films to bullet-proof jackets, etc. Such widely different applications rely on high variability in the physical properties of polyolefins, which is a result of variations in microstructure, chemical composition and molar mass. Though polyolefins contain only carbon (C) and hydrogen (H) atoms, the microstructures of polyolefins are extremely variable, differing in the nature of the monomers (e.g. ethylene versus propylene), the degree of branching, chemical composition in the case of copolymers and finally their molar masses. Production, research and development of polyolefins require the analysis of polyolefin samples in terms of all these parameters. Development of efficient and robust analytical techniques based on the interactive LC is reviewed. The needed computational/theoretical studies to understand the retention mechanism in the newly developed chromatography systems are discussed.

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High-temperature gradient HPLC for the separation of polyethylene–polypropylene blends

Cited by 61 publications

References 36 publications

Characterization of ethylene‐propylene copolymers with high‐temperature gradient adsorption liquid chromatography and CRYSTAF

Characterization of ethylene‐propylene copolymers with high‐temperature gradient adsorption liquid chromatography and CRYSTAF

Separation of polyolefins based on comonomer content using high‐temperature gradient adsorption liquid chromatography with a graphitic carbon column

A review on the development of liquid chromatography systems for polyolefins

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