Shear-dependent rheological properties of starch/bentonite composite gels
Küçük Resim Yok
Tarih
1997
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Dr Dietrich Steinkopff Verlag
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
Rheological properties of starch/bentonite gels (5.3-8.2% solids, 0-100% starch) were investigated at sheer rates 0.0083-0.33 s(-1) (Brookfield viscometer). Prior to these measurements the strain introduced during preparation of the gel was kept as low as possible. Under these conditions six different types of structural units could be identified in the gel: bentonite particles associated in a band-type structure; bands coated with starch polymers; bundles of bands interlaced and enveloped by starch polymers (strands), individual bentonite platelets dispersed in a polymer matrix; starch polymer networks; and swollen granules. A power-law model was fitted to the experimental viscosity data: mu(app) = K gamma(n-1). In all cases n was found to be less than 0.5. Its value decreased with the ability of the structural components to reorient under applied shear. K was found to be proportional to the compaction and/or entanglement of the structural units. These trends in K and n were further confirmed by the index of thixotropy (IT) and complex modulus of shear elasticity (G*) measurements.
Açıklama
Anahtar Kelimeler
bentonite, starch, rheology, viscosity, thixotropy, amylogram
Kaynak
Colloid and Polymer Science
WoS Q Değeri
Q1
Scopus Q Değeri
N/A
Cilt
275
Sayı
6
