Porous graphite as platform for the separation and characterization of synthetic polymers – an overview

Kot, David; Macko, Tibor; Arndt, Jan‐Hendrik; Brüll, Robert

doi:10.1016/j.chroma.2019.02.029

Cited by 20 publications

(10 citation statements)

References 73 publications

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“…The former is timeconsuming, while the latter suffers from a nonlinear detector response as a function of polymer composition and molecular weight. 1,2,10 HT-TGIC uses a temperature gradient to separate polyolefins according to comonomer content in an isocratic solvent. It enables the use of various commercial concentration detectors and/or molecular-weight-sensitive detectors such as laser light-scattering detectors.…”

Section: ■ Introductionmentioning

confidence: 99%

“…The distribution of this comonomer content is known as chemical composition distribution (CCD). Therefore, fast, precise, and accurate quantification of the CCD has been of interest for academic researchers − as well as the polyolefin industry for product characterization and differentiation, as described in hundreds of patents in the past 20 years.…”

Section: Introductionmentioning

confidence: 99%

“…The challenge in HT-SGIC is the lack of easy, fast, and quantitative detectors. For adequate quantification, either two-dimensional chromatography or evaporative light-scattering detection ,, must be used. The former is time-consuming, while the latter suffers from a nonlinear detector response as a function of polymer composition and molecular weight. ,, …”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Fabrication of Graphene-Coated Silica Particles for Polymer Chromatography to Quantify Chemical Composition Distribution of Polyolefin Materials

Cong¹,

Cheatham²,

Hollis³

et al. 2021

Macromolecules

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As the most consumed synthetic polymers globally, polyolefins provide tunable performance at a low production cost. This tunability is achieved by modifying polymer molecular weight or branching characteristics, the latter of which can be quantified by chemical composition distribution (CCD). CCD can be measured using interaction-based techniques relying on graphite-based material as the stationary phase. Interaction-based techniques are classified as solvent gradient or thermal gradient according to the type of gradient that is used to enable the separation of polyolefins. High-temperature thermal gradient interactive chromatography (HT-TGIC) has been the preferred technique as it overcomes the detector shortcomings of solvent gradient interactive chromatography. This work focuses on the HT-TGIC technique and strives to improve the separation resolution by adopting improvements in the stationary-phase packing material. Resolution is greatest with a substrate consisting of nonporous and homogeneous, spherical particles. However, the synthesis of such material with naturally occurring graphite has been a challenge. Here, an innovative yet simple approach to make such particles is described. A core–shell particle with nonporous silica as the core and graphene nanopowder (GNP) as the shell provides this solution. This novel method does not require chemical modification of graphene or silica particles, which has been explored previously as a potential avenue. These core–shell particles were packed into columns and showed an increase in chromatographic performance and separation resolution versus the best HT-TGIC columns currently available.

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Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Fabrication of Graphene-Coated Silica Particles for Polymer Chromatography to Quantify Chemical Composition Distribution of Polyolefin Materials

Cong¹,

Cheatham²,

Hollis³

et al. 2021

Macromolecules

View full text Add to dashboard Cite

show abstract

“…The stationary phase of choice for most research work has been porous graphitic and its use for polyolefin separations was reviewed recently. 126 However, in a rare example of research conducted on a stationary phase other than graphitic carbon, the separation of oxidized functionalized PE waxes were explored using a silica gel-based column. 94 In general, there lies a need for further research on alternative stationary phases for polyolefin separations.…”

Section: In Polyolefinsmentioning

confidence: 99%

Recent Advances in Separation-Based Techniques for Synthetic Polymer Characterization

et al. 2020

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“…TGIC is a chromatography exploiting the interaction between polymer chains and the graphitic stationary phase. [69][70][71][72][73][74][75][76] Above a critical value of chain length, the elution temperature (T e ) is almost independent of MW but dependent on the average length of the ethylene sequence for an ethylene/α-olefin random copolymer and on the total length of the ethylene sequence for a block copolymer. 69,74 Generally we reach the same conclusion as in CEF part: more heterogeneous composition is obtained at high rAl,Ti.…”

Section: Chemical Composition Distribution (Ccd) Of Copolymer Gpc-irmentioning

confidence: 99%

Engineering Poly(ethylene-co-1-butene) through Modulating the Active Species by Alkylaluminum

McKenna

Boisson

et al. 2020

ACS Catal.

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A SiO 2 /MgCl 2 -bisupported Ziegler-Natta type catalyst is studied in gas phase ethylene/1-butene copolymerization. With a minimal amount of alkylaluminum required to activate the catalyst, polymerization kinetics is profoundly affected by the dosage of it. High dosage of alkylaluminum retards the polymerization but does not kill the catalyst. Through a comprehensive characterization on the samples by DSC, CEF, TGIC, CFC and NMR, it has been showed that alkylaluminum also alters the short chain branching distribution (SCBD) of the copolymer but barely affects the total comonomer incorporation. It is proposed that alkylaluminum alters the active species from producing statistical copolymer chains to producing block polymer chains with C4-enriched and C4-scattered segments. It provides an example of bimetallic structure of active species as well as an approach to tailoring SCBD between statistical copolymer and block copolymer bearing C4-enriched and C4-scattered segments.

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Porous graphite as platform for the separation and characterization of synthetic polymers – an overview

Cited by 20 publications

References 73 publications

Fabrication of Graphene-Coated Silica Particles for Polymer Chromatography to Quantify Chemical Composition Distribution of Polyolefin Materials

Fabrication of Graphene-Coated Silica Particles for Polymer Chromatography to Quantify Chemical Composition Distribution of Polyolefin Materials

Recent Advances in Separation-Based Techniques for Synthetic Polymer Characterization

Engineering Poly(ethylene-co-1-butene) through Modulating the Active Species by Alkylaluminum

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