Eine vollständige Näherungsgleichung für den E-Modul als Funktion von Frequenz und Temperatur

Petroleum Heavy Ends Stability: Evolution of Residues Macrostructure by Aging

“…The behavior of the complex viscosity vs ω curves (see Figure ) are similar to those found when polymers with different average molecular weights ( M w ), but with same molecular weights distribution (MWD), were studied. − In the latter case, it was found that whereas the viscosity at higher frequencies hardly changed when increasing the molecular weight, the zero shear viscosity η 0 increased. With increasing molecular weights, even the onset of frequency-independent viscosity is shifted to lower frequency, as well.…”

“…The position of the crossover point (ω c , G c ) of G ‘ and G ‘ ‘ provides information on the molecular weight and molecular weight distribution of polymers, but it is not sensitive to changes in polymer structure. − The crossover frequency ω c is seen to be lower with increasing M w and almost independent of the molecular weight distribution; on the contrary, the crossover point modulus ( G c ) does not depend on the molecular weight, while it increases with decreasing broadness of the MWD.…”