Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
STUDIES OF CYCLIC AND LINEAR POLYDIMETHYLSILOXANES .32. DIELECTRIC-RELAXATION INVESTIGATIONS
Autore:
GOODWIN AA; BEEVERS MS; CLARSON SJ; SEMLYEN JA;
Indirizzi:
ASTON UNIV,DEPT CHEM ENGN & APPL CHEM BIRMINGHAM B4 7ET W MIDLANDS ENGLAND ASTON UNIV,DEPT CHEM BIRMINGHAM B4 7ET W MIDLANDS ENGLAND UNIV CINCINNATI,DEPT MAT SCI & ENGN CINCINNATI OH 45221 UNIV CINCINNATI,POLYMER RES CTR CINCINNATI OH 45221 YORK UNIV,DEPT CHEM YORK YO1 5DD N YORKSHIRE ENGLAND
Titolo Testata:
Polymer
fascicolo: 13, volume: 37, anno: 1996,
pagine: 2603 - 2607
SICI:
0032-3861(1996)37:13<2603:SOCALP>2.0.ZU;2-H
Fonte:
ISI
Lingua:
ENG
Soggetto:
POLY(DIMETHYL SILOXANES);
Keywords:
DIELECTRIC RELAXATION; POLYDIMETHYLSILOXANES; DIPOLE MOMENT;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
21
Recensione:
Indirizzi per estratti:
Citazione:
A.A. Goodwin et al., "STUDIES OF CYCLIC AND LINEAR POLYDIMETHYLSILOXANES .32. DIELECTRIC-RELAXATION INVESTIGATIONS", Polymer, 37(13), 1996, pp. 2603-2607

Abstract

The dielectric cu-relaxation of a series of narrow-molecular-weight fractions of cyclic and linear polydimethysiloxanes (PDMSs) has been investigated as a function of frequency in the temperature range 140.5-157.5 K. The temperature of the alpha-transition decreases with increasing chain length for cyclic PDMS and increases with increasing chain length for linear PDMS, in agreement with the previously reported differential scanning calorimetry (d.s.c.) glass transition. The cooperativity of the relaxation process, according to the Kohlrausch-Williams-Watts analysis, is greater in linear PDMS. The activation energy and molecular dipole moment increase with increasing chain length for both cyclic and linear molecular types. Experimental values of the dipole moment ratio are in good agreement with those measured by static dielectric techniques and with the theoretical long-chain value. Copyright (C)1996 Elsevier Science Ltd.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 29/09/20 alle ore 07:24:55