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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Ageing and structural changes in PDMS rubber investigated by time domain NMR

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Munaro, Ana P. [1, 2] ; da Cunha, Giovanni P. [3] ; Filgueiras, Jefferson G. [3] ; Pinto, Jose M. [4] ; Munaro, Marilda [5] ; de Azevedo, Eduardo R. [3, 6] ; Akcelrud, Leni C. [1]
Total Authors: 7
[1] Univ Fed Parana, UFPR, LaPPS, Paulo Scarpa Polymer Lab, POB 19081, BR-81531990 Curitiba, Parana - Brazil
[2] Lactec, Inst Dev Technol, POB 19067, BR-81531990 Curitiba, Parana - Brazil
[3] Univ Sao Paulo, IFSC, Phys Inst Sao Carlos, POB 369, BR-13560970 Sao Carlos, SP - Brazil
[4] Parana Power Co, Copel Distribut, BR-81200420 Curitiba, Parana - Brazil
[5] Educ Soc Univ Santa Catarina, UNISOCIESC, BR-81690300 Curitiba, Parana - Brazil
[6] Univ Fed Parana, UFPR, PIPE, Grad Program Engn & Mat Sci, POB 19011, BR-81531980 Curitiba, Parana - Brazil
Total Affiliations: 6
Document type: Journal article
Source: Polymer Degradation and Stability; v. 166, p. 300-306, AUG 2019.
Web of Science Citations: 0

H-1 Double Quantum (H-1 DQ) and Dipolar Filtered Magic Sandwich Echo (DF-MSE) methods were used to characterize the structural and dynamic modifications taking place during degradation of PDMS elastomeric networks. The samples were collected from an insulator extracted directly from the electrical wiring that was exposed during 12 years to harsh atmospheric conditions. Information obtained included soft to hard ratio, dynamics of soft mobile chains, crosslink/entanglement density. Measurements were made at various depths, from the surface to bulk and at various distances from the core of the equipment. Molecular relaxations were also accessed by Dynamical Mechanical Thermal Analysis (DMTA). More exposed regions tended to have a higher content of dynamically restricted regions, suggesting a higher degree of junctions due to crosslinking and/or chain entanglements. The heterogeneity of the networks was significantly larger at the insulator's surface, suggesting that the atmospheric exposure induces not only cross-link formation but also defects on the networks. (C) 2019 Elsevier Ltd. All rights reserved. (AU)

FAPESP's process: 17/24465-3 - NMR methods for plant cell wall characterization: development and applications to second generation biofuel technologies
Grantee:Eduardo Ribeiro de Azevedo
Support Opportunities: Program for Research on Bioenergy (BIOEN) - Regular Program Grants