Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
Dielectric analysis of epoxy-amine systems. 1. Conductivity and gelation
Autore:
Eloundou, JP;
Indirizzi:
Ecole Polytech Yaounde, Lab Mecan Mat & Construct, Yaounde, Cameroon EcolePolytech Yaounde Yaounde Cameroon & Construct, Yaounde, Cameroon
Titolo Testata:
EUROPEAN POLYMER JOURNAL
fascicolo: 8, volume: 35, anno: 1999,
pagine: 1473 - 1480
SICI:
0014-3057(199908)35:8<1473:DAOES1>2.0.ZU;2-H
Fonte:
ISI
Lingua:
FRE
Soggetto:
VARYING CHAIN LENGTHS; CROSS-LINKING; DIGLYCIDYL ETHER; CURING KINETICS; BISPHENOL-A; GEL POINT; RELAXATIONS; THERMOSETS; CURE; POLYMERIZATION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
27
Recensione:
Indirizzi per estratti:
Indirizzo: Eloundou, JP Ecoleonolytech Yaounde, Lab Mecan Mat & Construct, BP 8390, Yaounde, Camero Ecole Polytech Yaounde BP 8390 Yaounde Cameroon nde, Camero
Citazione:
J.P. Eloundou, "Dielectric analysis of epoxy-amine systems. 1. Conductivity and gelation", EUR POLYM J, 35(8), 1999, pp. 1473-1480

Abstract

To try to observe gelation phenomenon from the dielectric curves, the low-T-g epoxy-amine system (T-g infinity = -12 degrees C), based on diglycidyl ether of 1,4-butanediol (DGEBD) and 4,9-dioxa 1,12-dodecane diamine (4D) was studied during isothermal curings by means of microdielectrometry. The isothermal curings were done at 40, 50 and 60 degrees C. At these temperatures, this system only exhibits gelation phenomenon. Three different approaches were developed: (i) inflexion point as gelationcriterion; (ii) percolation theory; (iii) correlation between conductivityand viscosity. The first approach shows that the inflexion point is not the gel point. Both other approaches fail to describe the complete evolution of the epoxy-amine reactive systems during cure. This is due to the fact that at the gel point, the macroscopic viscosity diverges, whereas the conductivity values involve the ion motions, thus the local viscosities. So, there is no manifestation of gelation on dielectric curves. (C) 1999 Elsevier Science Ltd. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 15/07/20 alle ore 21:23:51