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Long-chain branched polypropylene: crystallization under high pressure and polymorphic composition

Identifikátory výsledku

  • Kód výsledku v IS VaVaI

    <a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F70883521%3A28110%2F21%3A63526139" target="_blank" >RIV/70883521:28110/21:63526139 - isvavai.cz</a>

  • Výsledek na webu

    <a href="https://link.springer.com/article/10.1007/s10973-020-09931-1" target="_blank" >https://link.springer.com/article/10.1007/s10973-020-09931-1</a>

  • DOI - Digital Object Identifier

    <a href="http://dx.doi.org/10.1007/s10973-020-09931-1" target="_blank" >10.1007/s10973-020-09931-1</a>

Alternativní jazyky

  • Jazyk výsledku

    angličtina

  • Název v původním jazyce

    Long-chain branched polypropylene: crystallization under high pressure and polymorphic composition

  • Popis výsledku v původním jazyce

    High-pressure crystallization and resulting polymorphic composition of long-chain branched polypropylene (LCB-PP) were studied and compared with common linear isotactic polypropylene (PP). Commercially available LCB-PP and PP with similar melt flow indexes were crystallized under several high pressures (20, 40, 80, 120 and 160 MPa) at constant cooling rate 5 °C min−1. Structure of crystallized samples was evaluated via wide-angle X-ray scattering, differential scanning calorimetry and scanning electron microscopy. It was shown that under low pressure LCB-PP crystallizes at higher crystallization temperature than PP due to its higher nucleating density. The opposite situation is observed at high pressures (120 and 160 MPa): crystallization temperature of PP exceeds that of LCB-PP as a negative effect of branching is pronounced. Polymorphic analysis proved that LCB-PP tends to crystallize into orthorhombic γ-form. This crystalline form becomes to be dominant at 40 MPa, and LCB-PP samples crystallized at 120 and 160 MPa contain solely γ-form. On the other hand, no pure γ-form sample was prepared from PP in this study, although positive effect of pressure on its formation is observed. Thermodynamic stability of LCB-PP crystalline structure is systematically lower compared to PP. With pronounced crystallization pressure, the melting peak broadens and finally splits, indicating the presence of dominant amount of γ-form in LCB-PP. In comparison with PP, crystallites in LCB-PP structure are considerably smaller due to lower crystal growth rate and higher nucleating density. © 2020, Akadémiai Kiadó, Budapest, Hungary.

  • Název v anglickém jazyce

    Long-chain branched polypropylene: crystallization under high pressure and polymorphic composition

  • Popis výsledku anglicky

    High-pressure crystallization and resulting polymorphic composition of long-chain branched polypropylene (LCB-PP) were studied and compared with common linear isotactic polypropylene (PP). Commercially available LCB-PP and PP with similar melt flow indexes were crystallized under several high pressures (20, 40, 80, 120 and 160 MPa) at constant cooling rate 5 °C min−1. Structure of crystallized samples was evaluated via wide-angle X-ray scattering, differential scanning calorimetry and scanning electron microscopy. It was shown that under low pressure LCB-PP crystallizes at higher crystallization temperature than PP due to its higher nucleating density. The opposite situation is observed at high pressures (120 and 160 MPa): crystallization temperature of PP exceeds that of LCB-PP as a negative effect of branching is pronounced. Polymorphic analysis proved that LCB-PP tends to crystallize into orthorhombic γ-form. This crystalline form becomes to be dominant at 40 MPa, and LCB-PP samples crystallized at 120 and 160 MPa contain solely γ-form. On the other hand, no pure γ-form sample was prepared from PP in this study, although positive effect of pressure on its formation is observed. Thermodynamic stability of LCB-PP crystalline structure is systematically lower compared to PP. With pronounced crystallization pressure, the melting peak broadens and finally splits, indicating the presence of dominant amount of γ-form in LCB-PP. In comparison with PP, crystallites in LCB-PP structure are considerably smaller due to lower crystal growth rate and higher nucleating density. © 2020, Akadémiai Kiadó, Budapest, Hungary.

Klasifikace

  • Druh

    J<sub>imp</sub> - Článek v periodiku v databázi Web of Science

  • CEP obor

  • OECD FORD obor

    10404 - Polymer science

Návaznosti výsledku

  • Projekt

  • Návaznosti

    V - Vyzkumna aktivita podporovana z jinych verejnych zdroju

Ostatní

  • Rok uplatnění

    2021

  • Kód důvěrnosti údajů

    S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Údaje specifické pro druh výsledku

  • Název periodika

    Journal of Thermal Analysis and Calorimetry

  • ISSN

    1388-6150

  • e-ISSN

  • Svazek periodika

    143

  • Číslo periodika v rámci svazku

    5

  • Stát vydavatele periodika

    NL - Nizozemsko

  • Počet stran výsledku

    7

  • Strana od-do

    "3377 "- 3383

  • Kód UT WoS článku

    000552776500006

  • EID výsledku v databázi Scopus

    2-s2.0-85086643216