Characterization of the Chemical Composition Distribution of Ethylene/1‐Alkene Copolymers with HPLC and CRYSTAF—Comparison of Results

Chitta, Rajesh; Macko, Tibor; Brüll, Robert; Boisson, Christophe; Cossoul, Emilie; Boyron, Olivier

doi:10.1002/macp.201400490

Cited by 21 publications

(22 citation statements)

References 52 publications

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“…A recent investigation in SGIC with different solvents does show the same results as in TGIC: TCB, being a better thermodynamic solvent for PE than DCB, results in lower elution volumes. And, 1‐decanol used as the poor solvent in solvent gradient elutes the polyolefins earlier than when 2‐octanol is used as the poor solvent in SGIC.…”

Section: Methodssupporting

confidence: 52%

Separation of Ethylene‐Propylene Copolymers by Crystallization and Adsorption Mechanisms. A Journey Inside the Analytical Techniques

Monrabal¹

2015

Macromolecular Symposia

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The separation of polyolefin copolymers in terms of composition has been typically performed by crystallization techniques. In the last years, a new liquid chromatography approach has become available that extends the range of composition analysis applicable towards higher comonomer content. Every technique has its capabilities and limitations, and the use of multiple hyphenated techniques is often required to provide unequivocal results for characterizing the microstructure of complex copolymers like high impact polypropylene. A good understanding of the individual separation mechanisms is essential to interpreting the obtained results properly, and this becomes a challenging task when dealing with ethylene-propylene copolymers or homopolymer blends. The separation of these resins by the existing techniques is discussed. The role of solvent and the adsorbent in the separation mechanisms is investigated and a comparison of crystallization and liquid adsorption chromatography with various types of adsorbents is presented.

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Section: Methodssupporting

confidence: 52%

Separation of Ethylene‐Propylene Copolymers by Crystallization and Adsorption Mechanisms. A Journey Inside the Analytical Techniques

Monrabal¹

2015

Macromolecular Symposia

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“…The resins show bimodalities in CCD, an indication of two chemically distinct populations. This is in sharp contrast with what has been observed with metallocene LLDPEs …”

Section: Resultscontrasting

confidence: 91%

Ethylene/1‐heptene copolymers as interesting alternatives to 1‐octene‐based LLDPE: Molecular structure and physical properties

Ndiripo

Joubert

Pasch

2015

J. Polym. Sci. Part A: Polym. Chem.

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Classical linear low density polyethylenes (LLDPEs) are copolymers of ethylene and 1-octene or 1-hexene, respectively. In the past, other 1-olefins have been tested as comonomers but the resulting LLDPEs were never commercialized as large scale products. The present study focuses on the use of 1-heptene as an interesting comonomer for the synthesis of LLDPE. For a comparison of the molecular structure and the physical properties of 1-heptene-and 1-octene-based LLDPEs, five Ziegler-Natta LLDPEs of varying comonomer contents based on 1-heptene and 1-octene, respectively, were acquired and analysed using advanced methods. The comonomer contents of the resins were between 0.35 and 6.4 mol %. Crystallization-based techniques revealed similar bimodal distributions that are due to the formation of copolymer and polyethylene homopolymer fractions. The compositional distribution of the copolymers was studied by high-temperature (HT) HPLC and HT-2D-LC. The analytical results indicate similar chemical heterogeneities and molar mass distributions of the two sets of LLDPE up to a comonomer content of 3 mol %. Similar to the molecular structure, the physical properties of the materials are quite similar. At comonomer contents of 3 mol % differences between the two sets of samples are seen that are attributed to differences in the abilities of 1-heptene and 1-octene in disrupting the crystal arrangements of the polymer chains in solid state. V C 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 962-975

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“…When a polymer sample consists of macromolecules, which substantially differ in their crystallinity, co-crystallization will be minimal [34,35]. Yet, when the crystallization temperatures of two polymers are close then co-crystallization of components can become significant, and as result components will not be completely separated one from another [34][35][36][37]45,46]. Co-crystallization has been studied in detail from the melt [47][48][49][50][51][52][53][54][55].…”

Section: Introductionmentioning

confidence: 98%

“…Temperature Rising Elution Fractionation (TREF) [17][18][19][20], Crystallization Analysis Fractionation (CRYSTAF) [21,[24][25][26][27][28][29][30][31][32][33][34][35][36][37], and Crystallization Elution Fractionation (CEF) [22] have been developed with the aim to deformulate semi-crystalline olefin copolymers according to their chemical composition. These techniques are based on the crystallization of macromolecules from a hot dilute solution in a temperature gradient.…”

Section: Introductionmentioning

confidence: 99%

Separation of bimodal high density polyethylene using multidimensional high temperature liquid chromatography

Prabhu

Brüll

Macko

et al. 2015

Journal of Chromatography A

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Characterization of the Chemical Composition Distribution of Ethylene/1‐Alkene Copolymers with HPLC and CRYSTAF—Comparison of Results

Cited by 21 publications

References 52 publications

Separation of Ethylene‐Propylene Copolymers by Crystallization and Adsorption Mechanisms. A Journey Inside the Analytical Techniques

Separation of Ethylene‐Propylene Copolymers by Crystallization and Adsorption Mechanisms. A Journey Inside the Analytical Techniques

Ethylene/1‐heptene copolymers as interesting alternatives to 1‐octene‐based LLDPE: Molecular structure and physical properties

Separation of bimodal high density polyethylene using multidimensional high temperature liquid chromatography

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