Influence of Partial Disentanglement of Macromolecules on the Rheological, Thermal, and Mechanical Properties of Polypropylene–Polyethylene Blends

The properties of compatibilized blends of polyethylene (PE) and polypropylene (PP), having reduced macromolecular entanglements, were studied. The density of PP macromolecular entanglements was controlled by prior disentangling in solution. The polymer ratio in the blend was 4:1 or 1:4. An ethylene...

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Main Authors: Justyna Krajenta, Magdalena Lipinska, Andrzej Pawlak
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Molecules
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Online Access:https://www.mdpi.com/1420-3049/30/8/1786
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author Justyna Krajenta
Magdalena Lipinska
Andrzej Pawlak
author_facet Justyna Krajenta
Magdalena Lipinska
Andrzej Pawlak
author_sort Justyna Krajenta
collection DOAJ
description The properties of compatibilized blends of polyethylene (PE) and polypropylene (PP), having reduced macromolecular entanglements, were studied. The density of PP macromolecular entanglements was controlled by prior disentangling in solution. The polymer ratio in the blend was 4:1 or 1:4. An ethylene–octene copolymer was used as a compatibilizer. The melt blending process resulted in good dispersion of the minority component, with slightly larger inclusions when more disentangled PP was used. Rheological studies confirmed the achievement of different entanglement densities of PP macromolecules in the blends. The partial disentanglement did not affect the thermal stability of the blends. During the isothermal crystallization studies, faster growth of PP spherulites was observed in the blend with reduced entanglements, which also influenced the entire crystallization process. The recovery time of equilibrium entanglement was investigated and it turned out to be 45 min if the blend was annealed at 190 °C, which was shorter than in the analogous homopolymer. Studies of tensile properties showed that in blends with a majority share of polyethylene, the elongation at break increased with the disentanglement of the minority component, due to better bonding of the blend components and thus the reduction in microcavitation.
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spelling doaj-art-bfc6e1ea8b314183be1989209b2ce9eb2025-08-20T02:18:04ZengMDPI AGMolecules1420-30492025-04-01308178610.3390/molecules30081786Influence of Partial Disentanglement of Macromolecules on the Rheological, Thermal, and Mechanical Properties of Polypropylene–Polyethylene BlendsJustyna Krajenta0Magdalena Lipinska1Andrzej Pawlak2Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, 90-363 Lodz, PolandInstitute of Polymer and Dye Technology, Lodz University of Technology, 90-537 Lodz, PolandCentre of Molecular and Macromolecular Studies, Polish Academy of Sciences, 90-363 Lodz, PolandThe properties of compatibilized blends of polyethylene (PE) and polypropylene (PP), having reduced macromolecular entanglements, were studied. The density of PP macromolecular entanglements was controlled by prior disentangling in solution. The polymer ratio in the blend was 4:1 or 1:4. An ethylene–octene copolymer was used as a compatibilizer. The melt blending process resulted in good dispersion of the minority component, with slightly larger inclusions when more disentangled PP was used. Rheological studies confirmed the achievement of different entanglement densities of PP macromolecules in the blends. The partial disentanglement did not affect the thermal stability of the blends. During the isothermal crystallization studies, faster growth of PP spherulites was observed in the blend with reduced entanglements, which also influenced the entire crystallization process. The recovery time of equilibrium entanglement was investigated and it turned out to be 45 min if the blend was annealed at 190 °C, which was shorter than in the analogous homopolymer. Studies of tensile properties showed that in blends with a majority share of polyethylene, the elongation at break increased with the disentanglement of the minority component, due to better bonding of the blend components and thus the reduction in microcavitation.https://www.mdpi.com/1420-3049/30/8/1786polypropylene–polyethylene blendsentanglementscrystallization
spellingShingle Justyna Krajenta
Magdalena Lipinska
Andrzej Pawlak
Influence of Partial Disentanglement of Macromolecules on the Rheological, Thermal, and Mechanical Properties of Polypropylene–Polyethylene Blends
Molecules
polypropylene–polyethylene blends
entanglements
crystallization
title Influence of Partial Disentanglement of Macromolecules on the Rheological, Thermal, and Mechanical Properties of Polypropylene–Polyethylene Blends
title_full Influence of Partial Disentanglement of Macromolecules on the Rheological, Thermal, and Mechanical Properties of Polypropylene–Polyethylene Blends
title_fullStr Influence of Partial Disentanglement of Macromolecules on the Rheological, Thermal, and Mechanical Properties of Polypropylene–Polyethylene Blends
title_full_unstemmed Influence of Partial Disentanglement of Macromolecules on the Rheological, Thermal, and Mechanical Properties of Polypropylene–Polyethylene Blends
title_short Influence of Partial Disentanglement of Macromolecules on the Rheological, Thermal, and Mechanical Properties of Polypropylene–Polyethylene Blends
title_sort influence of partial disentanglement of macromolecules on the rheological thermal and mechanical properties of polypropylene polyethylene blends
topic polypropylene–polyethylene blends
entanglements
crystallization
url https://www.mdpi.com/1420-3049/30/8/1786
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AT magdalenalipinska influenceofpartialdisentanglementofmacromoleculesontherheologicalthermalandmechanicalpropertiesofpolypropylenepolyethyleneblends
AT andrzejpawlak influenceofpartialdisentanglementofmacromoleculesontherheologicalthermalandmechanicalpropertiesofpolypropylenepolyethyleneblends