TY - JOUR
T1 - Rheological properties of lyotropic solutions of acetoxypropylcellulose in dimethylacetamide. A comparision with the thermotropic case
AU - Cidade, M. T.
AU - Leal, C. R.
PY - 2003
Y1 - 2003
N2 - The rheological properties of a thermotropic acetoxypropylcellulose (APC) were already described in previous works. In this work we present the rheological properties, viscosity, η, and first normal stress difference, N1, of lyotropic solutions of APC in dimethylacetamide (DMAc). The flow curve of the lyotropic solution presents the typical behavior for this type of system (Onogi and Asada Curve) however, contrary to what happens with that other lyotropic system, the APC/DMAc system presents a continuous increase of N1 in function of the shear rate, which we attribute to the fact that APC has higher flexibility than the other liquid crystalline polymers studied so far - namely hydroxypropylcellulose and poly-benzyl-L-glutamate - that present a negative N1 region, as well as a low molecular weight. We will also present some remarks concerning rheo-optical studies preformed with APC/DMAc, by comparison with previous studies on thermotropic APC.
AB - The rheological properties of a thermotropic acetoxypropylcellulose (APC) were already described in previous works. In this work we present the rheological properties, viscosity, η, and first normal stress difference, N1, of lyotropic solutions of APC in dimethylacetamide (DMAc). The flow curve of the lyotropic solution presents the typical behavior for this type of system (Onogi and Asada Curve) however, contrary to what happens with that other lyotropic system, the APC/DMAc system presents a continuous increase of N1 in function of the shear rate, which we attribute to the fact that APC has higher flexibility than the other liquid crystalline polymers studied so far - namely hydroxypropylcellulose and poly-benzyl-L-glutamate - that present a negative N1 region, as well as a low molecular weight. We will also present some remarks concerning rheo-optical studies preformed with APC/DMAc, by comparison with previous studies on thermotropic APC.
KW - First normal stress difference
KW - Lyotropic solutions
KW - Thermotropic systems
KW - Viscosity
UR - http://www.scopus.com/inward/record.url?scp=3142537355&partnerID=8YFLogxK
U2 - 10.1080/15421400390249871
DO - 10.1080/15421400390249871
M3 - Article
AN - SCOPUS:3142537355
SN - 1542-1406
VL - 404
SP - 95
EP - 105
JO - Molecular Crystals and Liquid Crystals
JF - Molecular Crystals and Liquid Crystals
ER -