Ageing and structural changes in PDMS rubber investigated by time domain NMR.
MUNARO, Ana P.; CUNHA, Giovanni Paro da; FILGUEIRAS, Jefferson Gonçalves; PINTO, José M.; MUNARO, Marilda; AZEVÊDO, Eduardo Ribeiro de; AKCELRUD, Leni C.
MUNARO, Ana P.; CUNHA, Giovanni Paro da; FILGUEIRAS, Jefferson Gonçalves; PINTO, José M.; MUNARO, Marilda; AZEVÊDO, Eduardo Ribeiro de; AKCELRUD, Leni C.
 Abstract: 1H Double Quantum (1H 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. | |
| Polymer Degradation and Stability |
| v. 166, p. 300-306 - Ano: 2019 |
| Fator de Impacto: 3,780 |
| http://dx.doi.org/10.1016/j.polymdegradstab.2019.06.008 |  @article={002949422,author = {MUNARO, Ana P.; CUNHA, Giovanni Paro da; FILGUEIRAS, Jefferson Gonçalves; PINTO, José M.; MUNARO, Marilda; AZEVÊDO, Eduardo Ribeiro de; AKCELRUD, Leni C.},title={Ageing and structural changes in PDMS rubber investigated by time domain NMR},journal={Polymer Degradation and Stability},note={v. 166, p. 300-306},year={2019}} |