dc.contributor.author |
Badia Valiente, José David |
|
dc.contributor.author |
Teruel-Juanes, Roberto |
|
dc.contributor.author |
Acebo, C. |
|
dc.contributor.author |
Gil Castell, O. |
|
dc.contributor.author |
Serra, A. |
|
dc.contributor.author |
Ribes Greus, A. |
|
dc.date.accessioned |
2019-11-12T11:01:03Z |
|
dc.date.available |
2021-01-10T05:45:05Z |
|
dc.date.issued |
2019 |
|
dc.identifier.uri |
https://hdl.handle.net/10550/72174 |
|
dc.description.abstract |
Dielectric Thermal Analysis (DETA) of a series of new thermoset obtained by click chemistry was performed. The new thermosets were obtained by a dual-curing process consisting in a first photochemical thiol-ene, followed by a thermal thiol-epoxy starting from an allyl-terminated hyperbranched poly(ethyleneimine) (HBPEI) and different proportions of diglycidylether of bisphenol A (DGEBA) and the corresponding stoichiometric proportions of pentaerythritol tetrakis (3-mercaptopropionate, PETMP). The dielectric behaviour was obtained experimentally supressing the conductive effects. Two sub-Tg intramolecular non-cooperative γ and β relaxations and an intermolecular cooperative α-relaxation were detected. The γ-relaxation was ascribed to the dipole orientation of the terminal thiol groups. Two γ relaxations γepo and γene were observed, according to the influence of the surroundings. Only thermosets with a content of flexible HBPEI/PETMP domains higher than a 50% w/w showed the γene relaxation at lower temperatures and higher frequencies. The β-relaxation was a non-Johari-Goldstein relaxation, ascribed to the dipole transfer of the linear CH2O(CO)CH2CH2 groups of the thiol constrained in the glassy state. The α-relaxation was ascribed to the long-term segmental movements of the thermosets, occurring during the transition from the glassy to the rubbery stage. A synergic effect of reducing the rigidity and compactness of the thermosets by the reduction of aromatic moieties of the DGEBA/PETMP units, and the increase of the flexibility induced by the addition of HBPEI/PETMP units affected the macromolecular movement of the thermosets. |
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dc.language.iso |
eng |
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dc.relation.ispartof |
European Polymer Journal, 2019, vol. 113, p. 98-106 |
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dc.rights.uri |
info:eu-repo/semantics/openAccess |
|
dc.source |
Badia Valiente, José David Teruel-Juanes, Roberto Acebo, C. Gil Castell, O. Serra, A. Ribes Greus, A. 2019 Dielectric spectroscopy of novel thiol-ene/epoxy thermosets obtained from allyl-modified hyperbranched poly (ethyleneimine) and diglycidylether of bisphenol A European Polymer Journal 113 98 106 |
|
dc.subject |
Ciència dels materials |
|
dc.subject |
Termoplàstics |
|
dc.title |
Dielectric spectroscopy of novel thiol-ene/epoxy thermosets obtained from allyl-modified hyperbranched poly (ethyleneimine) and diglycidylether of bisphenol A |
|
dc.type |
info:eu-repo/semantics/article |
|
dc.date.updated |
2019-11-12T11:01:03Z |
|
dc.identifier.doi |
https://doi.org/10.1016/j.eurpolymj.2019.01.001 |
|
dc.identifier.idgrec |
134923 |
|
dc.embargo.terms |
24 months |
|