Influence of chain extenders and chain end groups on properties of segmented polyurethanes. II. Dielectric study

 
see the original item page
in the repository's web site and access all digital files if the item*
share




1998 (EN)
Influence of chain extenders and chain end groups on properties of segmented polyurethanes. II. Dielectric study (EN)

Savelyev, YuV (EN)
Privalko, EG (EN)
Kanapitsas, A (EN)
Privalko, VP (EN)
Pissis, P (EN)
Akhranovich, ER (EN)

N/A (EN)

Thermally stimulated depolarization currents (TSDC) measurements (temperature range 77-300K) and broadband a.c. dielectric relaxation spectroscopy (frequency range 10 mHz-2 GHz) were employed to investigate molecular mobility and microphase separation in model segmented polyurethanes (SPUs) from oligotetramethylene glycol 1000, 4,4'-diphenylmethane diisocyanate and different chain extenders. The magnitude of the interfacial Maxwell-Wagner-Sillars (MWS) polarization TSDC peak and of d.c. conductivity have proved to sensitively reflect changes of the degree of microphase separation (DMS). The dielectric strength of both the primary and the secondary transition of the soft segments rich microphase are highest for the SPU with the highest DMS, whereas frequency (temperature) position and shape of the response are not significantly affected by DMS. (C) 1998 Elsevier Science Ltd. All rights reserved. (EN)

journalArticle

Molecular structure (EN)
Degree of microphase separation (EN)
Composition effects (EN)
Electric conductivity of solids (EN)
Polyurethanes (EN)
Dielectric relaxation (EN)
Segmented polyurethanes (EN)
Oligotetramethylene glycol (EN)
Diphenylmethane diisocyanate (EN)
Phase separation (EN)
Glycols (EN)
Primary and secondary transitions (EN)
Chain extenders (EN)
Maxwell Wagner Sillars (MWS) polarization (EN)
Thermally stimulated depolarization currents (TSDC) measurements (EN)

Εθνικό Μετσόβιο Πολυτεχνείο (EL)
National Technical University of Athens (EN)

Polymer (EN)

1998


ELSEVIER SCI LTD (EN)



*Institutions are responsible for keeping their URLs functional (digital file, item page in repository site)