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Интеллектуальная Система Тематического Исследования НАукометрических данных |
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Molecular Structure, Phase Composition, Melting Behavior and Chain Entanglements in the Amorphous Phase of High-Density Polyethylenesстатья
Статья опубликована в высокорейтинговом журнале
Статья опубликована в журнале из списка Web of Science и/или Scopus- Авторы: Litvinov, Victor; Deblieck, Rudy; Clair, Charles; Van den fonteyne, Winke; Lallam, Abdelaziz; Kleppinger, Ralf; Ivanov, Ries Dimitri A.;, Michael; Boerakker, Mark
- Журнал: Macromolecules
- Год издания: 2020
- Издательство: American Chemical Society
- Местоположение издательства: United States
- DOI: 10.1021/acs.macromol.0c00956
- Аннотация: A methodology for estimating the entanglement density in theamorphous phase of semicrystalline polyolefins was developed. The method isbased on the analysis of the density of physical network junctions in theamorphous phase by 1H NMR T2 relaxation experiments. The density of theentanglement network was estimated for melt- and high-pressure-crystallized highdensitypolyethylenes (HDPEs) at temperatures close to and graduallyapproaching melting. Its value is lower for high-pressure-crystallized HDPE thanfor the same melt-crystallized polymer. The network of entanglements ischaracterized by the fraction of entangled network chains, the weight-averagemolecular weight of the network chains between apparent chain entanglements,Me, and the volume average density of apparent chain entanglements. Theentanglement network was studied in a series of low- and high-molecular-weightHDPEs and bimodal HDPE samples with different molecular weight characteristics and densities controlled by different contents of the 1-butene comonomer. It turns out that the molecular weight characteristics of the HDPEs influence the entanglement network. The fraction of network chains and the average density of apparent chain entanglements decrease with decreasing molecular weight Mn due to the “dilution” effect caused by disentangled chain-end segments increasing the Me. The current methodology is of interest for studying the effect of crystallization conditions, molecular structures, and short-chain branches on phase composition, melting behavior, and chain entanglements in the amorphous phase of polyolefins. The method allows estimation of the fraction of network chains, which potentially can form tie-chain segments during deformation. The effect of short-chain branches and molecular weight characteristics on the creep response of polyolefins.
- Добавил в систему: Иванов Дмитрий Анатольевич