Autor segons l'article: Badia, J D; Teruel-Juanes, R; Acebo, C; Gil-Castell, O; Serra, A; Ribes-Greus, A
Departament: Química Analítica i Química Orgànica
Autor/s de la URV: Badia Aparicio, José María / Serra Albet, Maria Angels
Paraules clau: Viscosity Thermosets Thermoset Temperature Segmental cooperativity Secondary relaxations Polymers Polyamide Hyperbranched polymers Glass-transition Fragility Epoxy resin Electrical-conductivity Dynamics Dual-curing Dielectric analysis Dielectrc spectroscopy Complex Click chemistry
Resum: © 2019 Elsevier Ltd 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 γ epo and γ ene 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 γ ene relaxation at lower temperatures and higher frequencies. The β-relaxation was a non-Johari-Goldstein relaxation, ascribed to the dipole transfer of the linear –CH 2 –O–(C[dbnd]O)–CH 2 –CH 2 – 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.
Àrees temàtiques: Química Polymers and plastics Polymer science Physics and astronomy (miscellaneous) Physics and astronomy (all) Organic chemistry Odontología Materials chemistry Materiais Interdisciplinar General physics and astronomy Farmacia Engenharias iv Engenharias iii Engenharias ii Engenharias i Ciências ambientais Ciência de alimentos Ciência da computação Biotecnología Astronomia / física Arquitetura, urbanismo e design
Accès a la llicència d'ús: https://creativecommons.org/licenses/by/3.0/es/
ISSN: 00143057
Adreça de correu electrònic de l'autor: angels.serra@urv.cat josepmaria.badia@urv.cat josepmaria.badia@urv.cat josepmaria.badia@urv.cat
Identificador de l'autor: 0000-0003-1387-0358
Data d'alta del registre: 2024-11-02
Versió de l'article dipositat: info:eu-repo/semantics/acceptedVersion
Enllaç font original: https://www.sciencedirect.com/science/article/abs/pii/S0014305718322523?via%3Dihub
URL Document de llicència: https://repositori.urv.cat/ca/proteccio-de-dades/
Referència a l'article segons font original: European Polymer Journal. 113 98-106
Referència de l'ítem segons les normes APA: Badia, J D; Teruel-Juanes, R; 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. DOI: 10.1016/j.eurpolymj.2019.01.001
DOI de l'article: 10.1016/j.eurpolymj.2019.01.001
Entitat: Universitat Rovira i Virgili
Any de publicació de la revista: 2019
Tipus de publicació: Journal Publications