dc.contributor.author |
Lozovoi A. |
|
dc.contributor.author |
Mattea C. |
|
dc.contributor.author |
Hofmann M. |
|
dc.contributor.author |
Saalwaechter K. |
|
dc.contributor.author |
Fatkullin N. |
|
dc.contributor.author |
Stapf S. |
|
dc.date.accessioned |
2018-04-05T07:08:56Z |
|
dc.date.available |
2018-04-05T07:08:56Z |
|
dc.date.issued |
2017 |
|
dc.identifier.issn |
0021-9606 |
|
dc.identifier.uri |
http://dspace.kpfu.ru/xmlui/handle/net/129429 |
|
dc.description.abstract |
© 2017 Author(s). Segmental dynamics of a highly entangled melt of linear polyethylene-alt-propylene with a molecular weight of 200 kDa was studied with a novel proton nuclear magnetic resonance (NMR) approach based upon 1 H → 2 H isotope dilution as applied to a solid-echo build-up function I SE (t), which is constructed from the NMR spin echo signals arising from the Hahn echo (HE) and two variations of the solid-echo pulse sequence. The isotope dilution enables the separation of inter- and intramolecular contributions to this function and allows one to extract the segmental mean-squared displacements in the millisecond time range, which is hardly accessible by other experimental methods. The proposed technique in combination with time-temperature superposition yields information about segmental translation in polyethylene-alt-propylene over 6 decades in time from 10 -6 s up to 1 s. The time dependence of the mean-squared displacement obtained in this time range clearly shows three regimes of power law with exponents, which are in good agreement with the tube-reptation model predictions for the Rouse model, incoherent reptation and coherent reptation regimes. The results at short times coincide with the fast-field cycling relaxometry and neutron spin echo data, yet, significantly extending the probed time range. Furthermore, the obtained data are verified as well by the use of the dipolar-correlation effect on the Hahn echo, which was developed before by the co-authors. At the same time, the amplitude ratio of the intermolecular part of the proton dynamic dipole-dipole correlation function over the intramolecular part obtained from the experimental data is not in agreement with the predictions of the tube-reptation model for the regimes of incoherent and coherent reptation. |
|
dc.relation.ispartofseries |
Journal of Chemical Physics |
|
dc.title |
Segmental dynamics of polyethylene-alt-propylene studied by NMR spin echo techniques |
|
dc.type |
Article |
|
dc.relation.ispartofseries-issue |
22 |
|
dc.relation.ispartofseries-volume |
146 |
|
dc.collection |
Публикации сотрудников КФУ |
|
dc.source.id |
SCOPUS00219606-2017-146-22-SID85020693174 |
|