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

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>

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.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10404 - Polymer science

Projekt

—

Návaznosti

V - Vyzkumna aktivita podporovana z jinych verejnych zdroju

Rok uplatnění

2021

Kód důvěrnosti údajů

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

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