为加强和促进亚洲国家胶体与界面科学工作者之间的学术交流与合作，在国家自然科学基金委员会、中国化学会胶体与界面化学专业委员会和山东大学“985”工程的大力支持和资助下，由山东大学胶体与界面化学教育部重点实验室承办的第2届亚...为加强和促进亚洲国家胶体与界面科学工作者之间的学术交流与合作，在国家自然科学基金委员会、中国化学会胶体与界面化学专业委员会和山东大学“985”工程的大力支持和资助下，由山东大学胶体与界面化学教育部重点实验室承办的第2届亚洲胶体与界面科学大会（The 2nd Asian Conference on Colloids ＆ Interface Chemistry）于2007年10月27-31日在我校隆重举行。展开更多
Shear thickening implies that the viscosity of a fluid increases with increasing rates of shear. In the past work reported, all shear thickening phenomena were observed in concentrated solid/liquid colloidal suspensio...Shear thickening implies that the viscosity of a fluid increases with increasing rates of shear. In the past work reported, all shear thickening phenomena were observed in concentrated solid/liquid colloidal suspension. In this paper, the shear thickening was observed in colloidal dispersion gel, with very lower volume fraction, of partially hydrolyzed polyacrylamide(PHPA)/aluminum citrate. Colloidal dispersion gels are made of low concentrations of polymer and crosslinker. Polymer mass fractions normally range from 0.01% to 0.12%. In this concentration regime, there is not enough polymer to form a continuous network, so a conventional bulk type gel cannot form. Instead of a solution of separate gel bundles forms, and it is a mixture of predominantly intramolecular and minimal intermolecular crosslinks. In the work reported here, the colloidal dispersion gels are made of PHPA of 0 03%, KCl of 0.5%, thiourea of 0.1% and Al 3+ with a mass fractions range of 0—0 003%, the Al 3+ ∶PHPA mass ratio changes from 0 to 0.1. The critical shear rates(CSR) for the onset of shear thickening are about 200 s -1 for all CDG systems studied, i.e ., the Al 3+ ∶PHPA mass ratio don’t affect the CSR. In the lower shear regime than CSR shear thinning was observed and in the higher shear regime than CSR the shear thickening was observed. The shear thickening may be explained with cluster formation mechanism.展开更多
文摘为加强和促进亚洲国家胶体与界面科学工作者之间的学术交流与合作，在国家自然科学基金委员会、中国化学会胶体与界面化学专业委员会和山东大学“985”工程的大力支持和资助下，由山东大学胶体与界面化学教育部重点实验室承办的第2届亚洲胶体与界面科学大会（The 2nd Asian Conference on Colloids ＆ Interface Chemistry）于2007年10月27-31日在我校隆重举行。
文摘Shear thickening implies that the viscosity of a fluid increases with increasing rates of shear. In the past work reported, all shear thickening phenomena were observed in concentrated solid/liquid colloidal suspension. In this paper, the shear thickening was observed in colloidal dispersion gel, with very lower volume fraction, of partially hydrolyzed polyacrylamide(PHPA)/aluminum citrate. Colloidal dispersion gels are made of low concentrations of polymer and crosslinker. Polymer mass fractions normally range from 0.01% to 0.12%. In this concentration regime, there is not enough polymer to form a continuous network, so a conventional bulk type gel cannot form. Instead of a solution of separate gel bundles forms, and it is a mixture of predominantly intramolecular and minimal intermolecular crosslinks. In the work reported here, the colloidal dispersion gels are made of PHPA of 0 03%, KCl of 0.5%, thiourea of 0.1% and Al 3+ with a mass fractions range of 0—0 003%, the Al 3+ ∶PHPA mass ratio changes from 0 to 0.1. The critical shear rates(CSR) for the onset of shear thickening are about 200 s -1 for all CDG systems studied, i.e ., the Al 3+ ∶PHPA mass ratio don’t affect the CSR. In the lower shear regime than CSR shear thinning was observed and in the higher shear regime than CSR the shear thickening was observed. The shear thickening may be explained with cluster formation mechanism.
