posted on 2024-03-01, 17:53authored byMargarita Kruteva, Jürgen Allgaier, Michael Monkenbusch, Rustem Valiullin, Ingo Hoffmann, Dieter Richter
We present a quantitative comparison of the dynamic structure
factors
from unentangled and strongly entangled poly(butylene oxide) (PBO)
melts. As expected, the low molecular weight PBO displays Rouse dynamics,
however, with very significant subdiffusive center-of-mass diffusion.
The spectra from high molecular weight entangled PBO can be very well
described by the dynamic structure factor based on the concept of
local reptation, including the Rouse dynamics within the tube and
allowing for non-Gaussian corrections. Comparing quantitatively the
spectra from both polymers leads to the surprising result that their
spectra differ only by the contribution of classical Rouse diffusion
for the low molecular weight melt. The subdiffusive component is common
for both the low and high molecular weight PBO melts, indicating that
in both melts the same interchain potential is active, thereby supporting
the validity of the Generalized Langevin Equation approach.