Papers by Keyword: Rheology Properties

Abstract: Paper deals with utilization of fine ground ceramic powder as a supplementary cement addition. Present work follows previous research focused on the basic physical and hygric properties of cement composites with ceramic powder application. Present work introduce rheological, mechanical and fracture properties of cement pastes investigated during maturation at time 7 days. Presented data are added by results of pore characteristic having essential impact to final properties. Obtained data confirm previous assumption of retarding of hydration process, but final fracture properties indicate increased durability of cement pastes with fine ceramic powder addition.

Abstract: By means of mechanical properties test，the relationship among shear ratio, concentration and electric field, magnetic field, electromagnetic field on the Ni/TiO2/SDBS EMR fluid properties have been analyzed. It had found that with increasing shear ratio，the shear stress of Ni/TiO2/SDBS EMR fluid increased for same composition, but there is a critical value. With increasing concentration，the property of EMR fluid increased for same shear ratio. Coupling electromagnetic field makes the properties improve.

Abstract: In the present paper, mechanical properties test and morphology observation，the effect among electric field, magnetic field and electromagnetic field, shear ratio on the Ni/TiO₂/Urea core-shell particles electrorheological fluid properties were studied. It is found that with increasing electric field, magnetic field and shear ratio in the same composition electrorheological fluid, the property of electrorheological fluid can be increased. However, there is a critical value for shear ratio. When shear ratio is larger than 20s^-1, the property of ER is nearly certain value for same composition ER fluid. Electromagnetic field reciprocal effect can increase the properties of ER fluid, and make the particles chain become thicker and interweaved each other.

Abstract: By means of mechanical properties test，the relationship among shear ratio, concentration and electric field, magnetic field ,electromagnetic field on the Ni/TiO2 group electrorheological fluid properties have been analyzed. It is found that with increasing shear ratio，the property of electrorheological fluid increased for same composition ER, but there is a critical value. With increasing concentration，the property of electrorheological fluid increased for same shear ratio. Coupling electromagnetic field makes the properties improve.

Abstract: The comparison of binder system between PP/ palm stearin and PE/ palm stearin both mixed with palm stearin were studied based on the rheological properties to (MIM) process. The microstructure of distribution and dispersion studied using scanning electron microscope (SEM) to observe the pattern of the attached binder with stainless steel powder. The types of binder system used were palm stearin with Polypropylene (PP) and Polyethylene (PE). The powder loading for stainless steel 316L with average size of 20µm used was determined at 66 vol %. The palm stearin was the main significant factor for both viscosity and sensitivity of the feedstock behavior. Less content of palm stearin reduce the viscosity of the feedstock in the range of 100-10000 Pa.s and less influence on changing towards temperature and pressure. As the percentage of addition of palm stearin increase, the feedstock becomes less viscous with high sensitivity. PP and PE feedstock shows dilatant and pseudoplastic flow behavior respectively. PE homogenously coated each of stainless during morphology observation. Meanwhile poor distribution of PP can be observed from SEM observation at 1000x magnification.

Abstract: The injection molding of polymer composite is one of the promising and practical methods in the manufacturing of bipolar plates in mass production. Graphite filler with higher loading concentration is mainly used for this purpose. The particle size and composition (wt. %) of graphite filler material influences on the mechanical properties and electrical conductivity of composite materials. The main challenge is the reduction of flow ability during injection of high load filler material. Flow ability of feedstock material is an important factor in the process of injection molding. This paper presents a development of the rheology approach on the effect of particle size in material flow ability occurs in the injection molding process. Polypropylene (PP) as polymer matrix and graphite as conductive filler mixed together with different size to form feedstock material. Graphite purchase from local Asbury Graphite Mills, Inc, grade 3243 with particle size in average after sieve of ≤40, ≤100, and ≤150 μm. Proportions of polymer matrix and graphite at (PP / G) 25 / 75 wt. %. Mixing of graphite in PP matrix is done using an internal mixer (Thermo Haake) at 50 rpm, temperature at 200 oC. Rheology behaviors of graphite composite were measured using a capillary rheometer type Shimadzu CFT-500D, with a diameter 1 mm and length 10 mm. The fracture surface morphology was examined using scanning electron microscopy (SEM). The electrical conductivity of composite materials was measured by the four point probe. The hardness property measurement of conductive material composite was performed using a Dynamic ultra micro hardness tester using a Vickers typed diamond indenter. The results indicate that the level of viscosity and shear rate on all eligible mixed particle size capable of injectable. The properties of composite materials is the highest in three mix particle size (40/100/150 μm) for the electrical conductivity of 9.13 S.cm-1 and hardness at 34.3 HV. Viscosity of 56 Pa.s at a temperature of 200 oC and shear rates generated in 3231 s-1. The highest electrical conductivity for a single particle size is 49.2 S.cm-1 at 150 μm and hardness of Vickers to 47.2 HV at 100 um. The highest electrical conductivity and hardness due to the packing density and reinforcement different particle size.

Abstract: Carbon nanotubes/ iron compound powder was prepared by high energy ball milling after purified and activated the CNTs. Then, the compound powder and paraffin wax based-binders were mixed to prepare feedstock and the rheological behavior was evaluated by SEM, rheometer and infrared spectrum analysis. By changing the CNTs content and powder loading, the viscosity, shear rate sensitive factor and viscos-activation energy were calculated. 0.2wt% of CNTs, the feedstock can disperse in the binders uniformly without the flowability affecting. Meanwhile, adding proper ratio of CNTs can increase the powder loading of MIM feedstock about 10%, which can optimize the following process conditions and the properties of MIM product.