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Titolo:
BRILLOUIN AND NEUTRON INELASTIC-SCATTERING INVESTIGATION OF THE RELAXATIONAL PROCESSES IN GLASS-FORMING AND GEL-FORMING POLYMERS
Autore:
LEVELUT C; SCHEYER Y; PELOUS J; PROCHAZKA F;
Indirizzi:
UNIV MONTPELLIER 2,LAB VERRES,PL E BATAILLON F-34095 MONTPELLIER 5 FRANCE UNIV MAINE,LAB CHIM PHYSICOCHIM POLYMERES F-72017 LE MANS FRANCE
Titolo Testata:
Journal of non-crystalline solids
, volume: 235, anno: 1998,
pagine: 375 - 382
SICI:
0022-3093(1998)235:<375:BANIIO>2.0.ZU;2-R
Fonte:
ISI
Lingua:
ENG
Soggetto:
WILLIAMS-WATTS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
10
Recensione:
Indirizzi per estratti:
Citazione:
C. Levelut et al., "BRILLOUIN AND NEUTRON INELASTIC-SCATTERING INVESTIGATION OF THE RELAXATIONAL PROCESSES IN GLASS-FORMING AND GEL-FORMING POLYMERS", Journal of non-crystalline solids, 235, 1998, pp. 375-382

Abstract

An experimental study of the relaxational processes related to the glass transition in polyurethanes is presented. In these polymers, the crosslink density can be modified by changing the ratio of the two constituents (a three arm triol and a di-isocyanate) and a viscoelastic crossover is observed from a sol to a gel. The length between cross-links can be varied by changing the length of the arms of the triol. We used inelastic light and neutron scattering to determine the relaxation times, tau, in the 10(-8)-10(-12) s range. The high frequency relaxation splits from the structural relaxation deter mined from the lower frequency measurements. For both techniques we found that tau decreases when the length of the arms increases and tau depends on the crosslinkdensity when the arms of the triol are short; the variations of tau with the crosslink density are correlated to the one of the glass transition temperature. (C) 1998 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 02/12/20 alle ore 18:14:51