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Titolo:
FREE-VOLUME AND WATER-UPTAKE IN A COPOLYMER HYDROGEL SERIES
Autore:
HODGE RM; SIMON GP; WHITTAKER MR; HILL DJT; WHITTAKER AK;
Indirizzi:
MONASH UNIV CLAYTON VIC 3168 AUSTRALIA MONASH UNIV CLAYTON VIC 3168 AUSTRALIA UNIV VICTORIA MELBOURNE VIC 3000 AUSTRALIA UNIV QUEENSLAND,DEPT CHEM BRISBANE QLD 4067 AUSTRALIA UNIV QUEENSLAND,CTR MAGNET RESONANCE BRISBANE QLD 4067 AUSTRALIA
Titolo Testata:
Journal of polymer science. Part B, Polymer physics
fascicolo: 3, volume: 36, anno: 1998,
pagine: 463 - 471
SICI:
0887-6266(1998)36:3<463:FAWIAC>2.0.ZU;2-K
Fonte:
ISI
Lingua:
ENG
Soggetto:
POSITRON-ANNIHILATION LIFETIME; HOLE PROPERTIES; POLYMER BLENDS; SPECTROSCOPY; DISTRIBUTIONS; DEPENDENCE; ABSORPTION;
Keywords:
HYDROGEL; FREE VOLUME; POSITRON ANNIHILATION; WATER; DENSITY;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
41
Recensione:
Indirizzi per estratti:
Citazione:
R.M. Hodge et al., "FREE-VOLUME AND WATER-UPTAKE IN A COPOLYMER HYDROGEL SERIES", Journal of polymer science. Part B, Polymer physics, 36(3), 1998, pp. 463-471

Abstract

A copolymer of X-hydroxyethyl methacrylate (HEMA) with 2-ethoxy ethylmethacrylate (EEMA) was synthesized and the molecular mobility, free volume, and density properties examined as a function of composition. These properties were correlated with the equilibrium water uptake in order to determine which of the properties were most influential in causing high water sorption, as these materials are suitable candidates for hydrogel systems. It was found that the polar HEMA repeat unit results in a rigid, glassy sample at room temperature due to the high degree of hydrogen bonding between chains whereas high EEMA content leadsto rubbery samples with subambient glass transition temperatures. Thefree volume properties on the molecular scale measured by positron annihilation Lifetime spectroscopy (PALS) showed that higher HEMA content led to smaller, fewer holes and a lower free volume fraction than EEMA. Therefore the high water uptake of HEEMA-containing copolymers is largely related to the high polarity of the HEMA unit compared to EEMA, despite the low content of free volume into which the water can initially diffuse. Trends in density with copolymer composition, as measured on a macroscopic level, differs to that seen by PALS and indicates that the two techniques are measuring different scales of packing. (C)1998 John Wiley & Sons, Inc.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 10/04/20 alle ore 02:38:49