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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 |