High shear rate rheology of branched polypropylenes
The result's identifiers
Result code in 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>
Result on the web
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DOI - Digital Object Identifier
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Alternative languages
Result language
angličtina
Original language name
High shear rate rheology of branched polypropylenes
Original language description
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.
Czech name
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Czech description
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Classification
Type
O - Miscellaneous
CEP classification
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OECD FORD branch
10404 - Polymer science
Result continuities
Project
<a href="/en/project/GA16-05886S" target="_blank" >GA16-05886S: Investigation the effect of polymer melt shear and elongational rheology on production stability of meltblown nanofibers and films</a><br>
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)
Others
Publication year
2018
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů