Papers by Keyword: Rheological Property

Abstract: The local drug delivery based on mucoadhesion is an effective medical treatment. The mucoadhesive property relies on the formulated gel having optimized rheology. The addition of the drug also showed a major influence towards the sol-gel transition. In this study, compositional effect of Eudragit E100^® base polymer, various mucoadhesive polymers, and the black ginger extract on the rheological property of the formulated sol-gel was assessed. It was found that gelling point and gel strength could be tuned mainly based on the concentration of Eudragit E100 limited at 40% w/w due to the viscosity. At Eudragit E100 of 30% w/w, 0.5% w/w herbal extract, and 1%w/w polyvinyl alcohol, the solution reached the gel point at 286 s (tan δ=1) with the gel strength of 1 kPa (G’=G”). For all the formulated sol-gels, the rheological property became better (faster gelling point with the gel strength varying from 100-700 kPa at low strain) a simulated saliva environment.

Abstract: In this research, the influencing factors of oil well cement on the rheological property were experimentally studied. Based on the experiments and surveys of other class G oil well cement plants, the main influencing factors in the routine inspection were sample storage and processing condition and inspection equipment accuracy. The experimental results illustrate that sample storage and processing condition had a highly effect on the rheological property of drilling cement slurry. In addition, temperature positive deviation increased the rate of cement hydration by causing more rapid nucleation of hydration products, leading to earlier thickening time; conversely, minus deviation delayed cement nucleation, causing later thickening time. Compared with temperature deviation, the effect of pressure deviation was not obvious.

Abstract: In this paper, we used basalt fiber as an additive for improving the pavement performance of asphalt. We explored the effect of basalt fiber on the rheological property of asphalt mortar by dynamic shear rheometer techniques. Results indicate that basalt fiber causes an increase in complex modulus, storage modulus, loss modulus and rutting factor, while decrease in the phase angle and temperature susceptibility of asphalt mortar remarkablely. The regression relation between rutting factor and temperature closely fits Model ExpDec1. This improvement effect may be closely related to the microstructure of fibers such as large surface, polar groups on the surface, and the distribution state of fibers in asphalt mortar.

Abstract: Spheric SiO₂ nanoparticles with the sizes distribution between 20-80 nm dispersed in nonaqueous solvent were prepared under the assistance of surfactant. Shear emulsification time was a key role for the dispersion of nanoparticles and the optimal value was 30 min with the smallest median size of 51 nm. The relationship between fluid viscosity and dispersion condition was researched, and the results demonstrated that the additional volume arising from aggregation interspaces enhanced shear fore and opposite resistance and finally the viscosity increased.

Abstract: Palygorskite/polyacrylamide (PAM) composited thickeners were prepared via in-situ polymerization. To optimize the preparation, the dependence of the viscosity, rheological properties and electrolyte resistance of the composited thickeners on the initiator concentrations, sodium hydroxide concentrations and palygorskite contents was investigated. By measuring their dynamic rheological properties, thickening mechanism of composited thickeners was explored. The composited thickeners showed excellent electrolyte resistance which represented good synergistic effect of inorganic/organic composited thickener.

Abstract: A fluid system consisting of polymer-based thickening agent (ACPAM) and a surfactant (Linear alkyl benzene sulfonate, LAS) is reported. The ACPAM polymer showed good thickening performance. At concentration 0.6 wt%, the viscosity of ACPAM solution reached 265 mPa∙s. ACPAM polymer solution was easily cross-linked by LAS at a wide pH range. The ACPAM gel system can be broken by ammonium persulfate under the temperature of 80~90°C. The residue content of the breaking fluid was low. Meanwhile, the ACPAM fluid system showed an excellent thermal stability & shearing resistance performance. It can be used in high temperature reservoir upto temperature 150°C.

Abstract: This paper is based on the research of the coal water slurry rheological property and stability. The influence of the concentration, additives and temperature on the rheological properties of the slurry has also been studied. The apparent viscosity increases with increasing concentration of coal water slurry, and decreases with increasing temperature. An introduction of additives can greatly improve the rheological properties of coal water slurry. The stability of coal water slurry increases with the increase of concentration, and the stability decreases with the increase of temperature. A proper amount of additives can improve its stability.

Abstract: Zirconium diboride (ZrB2) ceramics were synthesized by Aqueous gelcasting method sintering effects of the additives were examined. The dispersion and rheological properties behavior of water-based gelcasting ZrB2-4wt.%B4C suspensions were characterized by zeta potential and viscosity measurements, respectively. A 50 vol.% ZrB2-4wt.%B4C suspension with a relative low viscosity was prepared with 3wt.% A70 and 4wt.% AM at pH = 11. Using the liquid desiccant drying method, the weight loss was 7.7 % after drying for 24 h, which is higher than the drying at RT (7.2 %).

Abstract: Adding different kinds of additives will change rheological properties of cement slurry, same to the concrete. The relationship between fluid shear stress (Γ) and the shear rate (Ds) called rheological properties. In this paper we studied the influence of different additives (Olyacryamide, polycarboxylate superplasticizer , nanoCaCO₃) on the slurry rheological properties and the effects of polyacrylamide on cement mortar liquidity.

Abstract: In recent years, multi-component injection molding has largely developed in the industries. During the manufacturing process, the critical challenge is in achieving an optimum adhesion between the two materials. This study examines the influence of curing kinetics on the interfacial adhesion strength between a silicone rubber and nylon 66 using a rotational rheometer. The evolution of adhesion strength of assembly during the curing behaviour of silicone rubber was measured by tensile test at different curing temperature and different curing time. The results showed a significant increase in adhesion was obtained while either the curing temperature or the curing time increased. In this study, the rheological property of silicone rubber fluid has been also determined by the rotational rheometer. In addition, the kinetics of the curing reaction of silicone rubber has been studied by differential scanning calorimeter.