High shear rate rheology of branched polypropylenes

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F70883521%3A28110%2F18%3A63520668" target="_blank" >RIV/70883521:28110/18:63520668 - isvavai.cz</a>

Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

High shear rate rheology of branched polypropylenes

Popis výsledku v původním jazyce

Dynamics of linear polypropylene (L-PP) and long-chain branched polypropylene (LCB-PP) miscible blends, having weight average molecular weight between 64-78 kg/mol, was investigated via high shear rate rheology. Results obtained were compared with the corresponding data for L-PP. High-shear rate secondary Newtonian plateaus, , were identified at three different temperatures for well entangled L-PP/LCB-PP blends above shear rates of 2·106 1/s and their dependence on weight average molecular weight, Mw, was successfully related as η∞(T)=K∞(T)·Mwn with the exponent n=1.010. Interestingly, the temperature dependent proportionality constant K was found to be about 10-20% lower for the blend in comparison with the pure L-PP whereas the parameter n was found to be the same for both systems. The average values of high-shear rate flow activation energy, E, for the blends was found to be slightly lower than for pure L-PP and comparable with low-shear rate flow activation energy of PP like oligomer squalane (C30H62; 2,6,10,15,19,23-hexamethyltetracosane). This suggests that polymer chains are fully disentangled at very high shear rates and chain branching can enhance the flow in this regime due to smaller coil size and higher availability of the free volume (i.e. lower monomeric friction coefficient) in comparison with their linear counterparts.

Název v anglickém jazyce

High shear rate rheology of branched polypropylenes

Popis výsledku anglicky

Dynamics of linear polypropylene (L-PP) and long-chain branched polypropylene (LCB-PP) miscible blends, having weight average molecular weight between 64-78 kg/mol, was investigated via high shear rate rheology. Results obtained were compared with the corresponding data for L-PP. High-shear rate secondary Newtonian plateaus, , were identified at three different temperatures for well entangled L-PP/LCB-PP blends above shear rates of 2·106 1/s and their dependence on weight average molecular weight, Mw, was successfully related as η∞(T)=K∞(T)·Mwn with the exponent n=1.010. Interestingly, the temperature dependent proportionality constant K was found to be about 10-20% lower for the blend in comparison with the pure L-PP whereas the parameter n was found to be the same for both systems. The average values of high-shear rate flow activation energy, E, for the blends was found to be slightly lower than for pure L-PP and comparable with low-shear rate flow activation energy of PP like oligomer squalane (C30H62; 2,6,10,15,19,23-hexamethyltetracosane). This suggests that polymer chains are fully disentangled at very high shear rates and chain branching can enhance the flow in this regime due to smaller coil size and higher availability of the free volume (i.e. lower monomeric friction coefficient) in comparison with their linear counterparts.

Druh

O - Ostatní výsledky

CEP obor

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OECD FORD obor

10404 - Polymer science

Projekt

<a href="/cs/project/GA16-05886S" target="_blank" >GA16-05886S: Výzkum vlivu smykové a tahové reologie polymerních tavenin na stabilitu produkce meltblown nanovláken a fólií</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2018

Kód důvěrnosti údajů

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