TY  - JOUR
AU  - Gold, Barbara
AU  - Hövelmann, Claas
AU  - Lühmann, N.
AU  - Pyckhout-Hintzen, W.
AU  - Wischnewski, A.
AU  - Richter, D.
TI  - The microscopic origin of the rheology in supramolecular entangled polymer networks
JO  - Journal of rheology
VL  - 61
IS  - 6
SN  - 1520-8516
CY  - Melville, NY [u.a.]
PB  - Inst.
M1  - FZJ-2017-07560
SP  - 1211 - 1226
PY  - 2017
AB  - Supramolecular groups in polymeric systems lead to responsive materials which are ideally suited for applications in dynamic environments. The key to their advanced properties such as shape-memory or self-healing is the reversibility of secondary interactions which can be triggered by external stimuli such as temperature, light, or pH-value. Controlling the (mechanical) behavior of such systems requires a precise understanding of intrinsic properties. We present a multimethod study of transient polyisoprene networks that were functionalized with different amounts of hydrogen bonding urazole groups. This work aims at understanding rich rheological features on the basis of their microscopic origin. First, the thermorheological simple behavior is validated experimentally. Subsequently, we characterize the underlying microscopic processes by broadband dielectric spectroscopy (α-process and α∗-process), differential scanning calorimetry (glass transition behavior), and Fourier-transform infrared spectroscopy (thermodynamics of group association/dissociation). Based on these results, the influence of the supramolecular groups on the rheological response is analyzed. The observed features such as the onset of elastomeric properties in the flow regime, a drastic increase in the chain relaxation time with an increasing amount of functional groups, and the occurrence of a second rheological relaxation process, which is the most prominent effect, are discussed and related to their physical origin.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000414273200016
DO  - DOI:10.1122/1.4998159
UR  - https://juser.fz-juelich.de/record/839990
ER  -