http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Effect of associating polymer on the dispersion stability and rheology of suspensions
Otsubo, Yasufumi,Horigome, Misao The Korean Society of Rheology 2003 Korea-Australia rheology journal Vol.15 No.1
Associating polymers are hydrophilic long-chain molecules to which a small amount of hydrophobic groups (hydrophobes) is incorporated. In aqueous solution, the association interactions result in the formation of three-dimensional network through flowerlike micelles at high concentrations. In colloidal suspensions, the associating polymers act as flocculated by bridging mechanism. The rheological properties of suspensions flocculated by associating polymers end-capped with hydrophobes are studied in relation to the bridging conformation. At low polymer concentrations, the polymer chains effectively form bridges between particles by multichain association. The suspensions are highly flocculated and show typical viscoelastic responses. When the polymer concentration is increased above the absorbance at saturation, the excess polymer chains remaining in the solution phase build up three-dimensional network by associating interactions. Since the presence of particles does not significantly influence the network structures in the medium, the relative viscosity, which gives a measure of the degree of flocculation is decreased with increasing polymer concentration. The bridging conformation and flocculation level vary strongly depending on the polymer concentrations.
Effect of surfactant adsorption on the rheology of suspensions flocculated by associating polymers
Otsubo, Yasufumi,Horigome, Misao The Korean Society of Rheology 2003 Korea-Australia rheology journal Vol.15 No.4
Associating polymers act as flocculants in colloidal suspensions, because the hydrophobic groups (hydrophobes) can adsorb onto particle surfaces and create intermolecular cross-linking. The steady-shear viscosity and dynamic viscoelasticity were measured for suspensions flocculated by multichain bridging of associating polymers. The effects of surfactant on the suspension rheology are studied in relation to the bridging conformation. The surfactant molecule behaves as a displacer and the polymer chains are forced to desorb from the particle surfaces. The overall effect of surfactant is the reduction of suspension viscosity. However, the additions of a small amount of surfactant to suspensions, in which the degree of bridging is low, cause a viscosity increase, although the number of chains forming one bridge is decreased by the forced desorption of associating polymer. Since the polymer chains desorbed from one bridge can form another bridge between bare particles, the bridging density over the system is increased. Therefore, the surfactant adsorption leads to a viscosity increase. The surfactant influences the viscosity in two opposing ways depending on the degree of bridging.
정원식,남수용,대평태문 한국공업화학회 1998 응용화학 Vol.2 No.1
In this paper from a practical point of view, the viscosity behavior is studied for three different suspensions; UV inks, aqueous lattices, and electrorheological fluids. (1)After the printing process, the UV inks are rapidly cured old exposure to UV irradiation. To evaluate the sensitivity, the viscosity changes in curing are measured by the use of an oscillating plate rheometer newly-developed. (2)The flow of flocculated suspensions is generally pseudoplastics, because the floc structure are progressively broken down with increasing shear rate. When the polymer chains do not have strong affinity for the particle surfaces, the absorption-desorption of polymer occurs reversibly by thermal energy. (3)The electrorheological(ER) fluids are rapidly and reversibly converted between Newtonian fluids Bingham bodies on the application or removal of electric fields. Although the primary method of formulating excellent ER fluides is high dielectric particles, the surface polarization plays an essential role. The surface modification has great potential in the ER technology.