TY - JOUR
T1 - Chemorheology of aqueous-based alumina-poly(vinyl alcohol) gelcasting suspensions
AU - Morissette, Sherry L.
AU - Lewis, Jennifer A.
PY - 1999
Y1 - 1999
N2 - A new gelcasting system based on aqueous-based alumina-poly(vinyl alcohol) (PVA) suspensions cross-linked by an organotitanate coupling agent has been developed. The chemorheological properties of this system exhibited a strong compositional dependence. A sol-gel phase diagram was established, which yielded the critical titanium concentration ([Ti]c) required for gelation at a given PVA volume fraction as well as the minimum PVA volume fraction (φPVAmin = 0.0245) and titanium concentration ([Ti]min = 9.984×10-4 g of Ti/mL) below which gelation was not observed irrespective of solution composition. The gelation time of suspensions of constant PVA volume fraction (φPVAsoln) decreased with increased cross-linking agent concentration, temperature, and solids volume fraction. The steady-state viscosity and elastic modulus of polymer solutions (φPVAsoln = 0.05) of varying [Ti] were well described by the percolation model, giving scaling exponents of 0.84 and 1.79, respectively. The steady-state elastic modulus of gel-casting suspensions, which provided a measure of their handling strength in the as-gelled state, increased with increased solids volume fraction.
AB - A new gelcasting system based on aqueous-based alumina-poly(vinyl alcohol) (PVA) suspensions cross-linked by an organotitanate coupling agent has been developed. The chemorheological properties of this system exhibited a strong compositional dependence. A sol-gel phase diagram was established, which yielded the critical titanium concentration ([Ti]c) required for gelation at a given PVA volume fraction as well as the minimum PVA volume fraction (φPVAmin = 0.0245) and titanium concentration ([Ti]min = 9.984×10-4 g of Ti/mL) below which gelation was not observed irrespective of solution composition. The gelation time of suspensions of constant PVA volume fraction (φPVAsoln) decreased with increased cross-linking agent concentration, temperature, and solids volume fraction. The steady-state viscosity and elastic modulus of polymer solutions (φPVAsoln = 0.05) of varying [Ti] were well described by the percolation model, giving scaling exponents of 0.84 and 1.79, respectively. The steady-state elastic modulus of gel-casting suspensions, which provided a measure of their handling strength in the as-gelled state, increased with increased solids volume fraction.
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U2 - 10.1111/j.1151-2916.1999.tb01796.x
DO - 10.1111/j.1151-2916.1999.tb01796.x
M3 - Article
AN - SCOPUS:0032648275
SN - 0002-7820
VL - 82
SP - 521
EP - 528
JO - Journal of the American Ceramic Society
JF - Journal of the American Ceramic Society
IS - 3
ER -