The chemical composition distribution (CCD) of three single site made ethylene/1-octene copolymers was investigated through offline-hyphenation of solvent gradient interaction chromatography (SGIC) with H NMR. Thus, a clear, non-linear correlation between SGIC elution time and chemical composition was found under the specific measurement conditions applied here. The application of H NMR as detection allowed to determine the CCD with unprecedented accuracy. 2D-LC of the copolymers revealed the correlation between CCD and molar mass distribution (MMD) in a quantitative manner. Furthermore, this approach allowed a comparison between the response behavior of an evaporative light scattering detector (ELSD, semi-quantitative, commonly applied in SGIC) and that of an infrared (IR) detector (quantitative, commonly applied in SEC). As a result, it could be shown that ELSD results are close to IR results for the system investigated here, in other words, the often-criticized semi-quantitative response behavior of the ELSD is affecting results in an acceptable manner.
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http://dx.doi.org/10.1016/j.chroma.2020.461081 | DOI Listing |
Polymers (Basel)
November 2024
College of Petrochemical Engineering, Liaoning Petrochemical University, Fushun 113001, China.
Ethylene/1-octene copolymers exhibit enhanced flexibility and impact resistance compared to polyethylene, which makes them well suited for applications in advanced plastics and elastomers. United-atom molecular dynamics (MD) simulations were conducted to explore the mechanical behavior and deformation mechanisms of ethylene/1-octene copolymers under uniaxial tensile loading. This study systematically examined the influence of temperature, polymer chain length, chain quantity, and strain rate, with a specific focus on how hexyl branch content impacts the mechanical properties of amorphous ethylene/1-octene copolymers.
View Article and Find Full Text PDFACS Macro Lett
August 2024
Chair of Technical Thermodynamics and Energy Efficient Material Treatment, Institute for Energy Process Engineering and Fuel Technology, Clausthal University of Technology, Agricolastraße 4, 38678 Clausthal-Zellerfeld, Germany.
The relationship between macromolecular architecture and crystallization properties is a relevant research topic in polymer science and technology. The average degree of crystallinity of disperse polymers is a well-studied quantity and is accessible by various experimental methods. However, how the different macromolecular species contribute to the degree of crystallinity and, in particular, the relationship between a certain macromolecular architecture and the degree of crystallinity are not accessible today, neither experimentally nor theoretically.
View Article and Find Full Text PDFSoft Matter
May 2024
School of Materials Science and Engineering, Tianjin University, Tianjin 300072, P. R. China.
Chain flexibility or stiffness based polymer conformation plays a crucial role in affecting the dynamics and kinetics of polymers, which is related to the hierarchical architecture of chains. A series of random copolymers of ethylene and 1-alkenes including 1-hexene, 1-octene, and 1-dodecene were synthesized with metallocene catalysts. The crystallization behavior and memory effect in random ethylene-1-alkene copolymers with different side groups were investigated differential scanning calorimetry (DSC) and wide-angle X-ray scattering (WAXS).
View Article and Find Full Text PDFPolymers (Basel)
February 2024
College of Petrochemical Engineering, Liaoning Petrochemical University, Fushun 113001, China.
The performance of ethylene/1-octene copolymer primarily depends on the microstructure of the polymer chain. This study employed a new method to control the inter-distribution of hexyl chain branches directly on the backbone of the ethylene/1-octene copolymer. Three ethylene/1-octene copolymers with different inter-distributions of hexyl chain branches were synthesized using [MeSi(CMe) (NBu)] TiCl (Ti-CGC) by different feeding sequences in the semi-continuous polymerization reaction system.
View Article and Find Full Text PDFPolymers (Basel)
January 2024
Institute of Chemistry, University of Opole, Oleska 48, 45-052 Opole, Poland.
A series of ethylene/1-octene copolymers synthesized with diamine-bis(phenolate) complexes activated with Al(Bu)/[PhC][B(CF)] were subjected to preparative temperature rising elution fractionation (TREF). The complexes used differed in the type of metallic center (Zr or Ti) or the amine donor in the pendant arm of the ligand (NMe or NPr). The obtained fractions were then characterized via FTIR, DSC and GPC methods.
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