Transient and quasi-permanent networks in xyloglucan solutions.
Carbohydr Polym
; 129: 216-23, 2015 Sep 20.
Article
em En
| MEDLINE
| ID: mdl-26050908
ABSTRACT
Viscoelastic properties of aqueous solutions of xyloglucan extracted from Hymenaea courbaril seeds (Jatobá gum) were investigated by rheology over a wide range of concentrations and temperatures. The polymer was characterized in dilute solutions by light scattering measurements and size exclusion chromatography. Xyloglucan formed, in semi-dilute solutions (C 0.3 wt%), a transient network with cross-links characterized by a broad distribution of lifetimes, independent of the temperature and concentration. Progressively, at higher temperatures (>60°C), a second much weaker quasi-permanent network was formed and attributed to the exchange of intra- to inter-chain bonds. The stiffness of the second network increased with decreasing temperature, but it could be easily broken by applying a relatively weak shear stress and is readily reversible on re-heating, and partially reversible on resting at 20°C.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Xilanos
/
Hymenaea
/
Glucanos
Idioma:
En
Revista:
Carbohydr Polym
Ano de publicação:
2015
Tipo de documento:
Article