• Journal of Applied Biological Chemistry
• /
• v.50 no.4
• /
• pp.234-238
• /
• 2007

The effects of ultra-fine pulverization on the physicochemical properties of rice starch (RS) were investigated using a high impact planetary mill. After pulverization, RVA characteristics, peak viscosity, break down, and set back values of RS decreased from 274.75 to 9.42 RVU, 214.46 to 6.17 RVU, and 87.80 to 17.00 RVU, respectively. The pasting properties also changed significantly. X-Ray diffractogram revealed RS had four A-type peaks, which disappeared after pulverization. The peak temperature and gelatinization enthalpy of RS using differential scanning calorimetry (DSC) were 13.99 J/g at $75.14^{\circ}C$, whereas the pulverized RS (PRS) had two peaks, 0.13 J/g at $63.88^{\circ}C$ and 1.23 J/g at $101.24^{\circ}C$. DSC measurement showed the retrogradation degree of PRS was lower than that of RS after storage at 4 and $25^{\circ}C$. The enzymatic (${\alpha}$-amylase) digestibilities of RS and PRS were 72.7 and 77.3%, respectively.

• YAKHAK HOEJI
• /
• v.46 no.2
• /
• pp.102-107
• /
• 2002

The particle size of medicinal materials is an important physical property which affects the pharmaceutical behaviors such as dissolution, chemical stability, compressibility and bioavailability of solid dosage forms. The size reduction of raw pharmaceutical powder is needed to formulize insoluble drugs or slightly soluble drugs and to improve the pharmaceutical properties such as the solubility, the pharmaceutical mixing and the dispersion. The objective of the present study is to evaluate the grinding characteristics of ursodeoxycholic acid(UDCA) as a model of insoluble drugs. The effects of the grinding time and the amount of additive on particle size distribution of ground UDCA were investigated. Grinding of insoluble drug, UDCA and a series of dry co-grinding experiments of UDCA with sodium lauryl sulfate(SLS) as an additive were carried out using a planetary ball mill. It was measured that the median diameter and the particle size distribution of ground products with grinding UDCA and additive SLS by Mastersizer. As a result of co-grinding of UDCA and SLS, the particle size of co-grinding products was decreased more than single grinding one. However, it was observed that co-grinding products were reaggregated to larger particles after 120 min.

• Transactions of the Korean hydrogen and new energy society
• /
• v.10 no.2
• /
• pp.91-99
• /
• 1999

Under Hydrogen atmosphere, composites of Mg-Ni-Graphite were prepared by mechanical alloying(M.A.) using planetary mill. Mechanically alloyed powders were analyzed by XRD, SEM and automatic PCT. From the results of XRD, Mg-Ni-Graphite Composites were obtained successfully after 168hrs M.A. By the PCT test, synthesized powders were absorbed 4.9 wt% hydrogen at 623K.

• Proceedings of the IEEK Conference
• /
• 2001.10a
• /
• pp.315-324
• /
• 2001

Mechanochemical effects that occurred in the fine grinding process of quartz particles using planetary ball mill was investigated. Quartz particles have been frequently utilized for optical materials, semiconductor molding materials. We determined that grinding for a long time can be create amorphous structures from the crystalline quartz by Mechanochemical effects. But, to be produced nano-composite particles that the critical grinding time reached for composite materials in a short time. Henceforth, a qualitative estimation must be conducted on the filler for EMC(Epoxy molding compound) materials. It can be produced mechanochemically treated composite materials and also an integrated grinding efficiency considering of the nano-composite amorphous structured particles. The mechanochemical characteristics were evaluated based on particle morphology, size distribution, specific surface area, density and the amount of amorphous phase materials into the particle surface. The grinding operation in the planetary ball mill can be classified into three stages. During the first stage, initial particle size was reduced for the increase of specific surface area. In the second stage, the specific surface areas increased in spite of the increase in particle size. The final stage as a critical grinding stage, the ground quartz was considered mechanochemically treated particles as a nano- composite amorphous structured particles. The development of amorphous phase on the particle surface was evaluated by X-ray diffractometry, thermal gravity analysis and IR spectrometer. The amount of amorphous phase of particles ground for 2048 minutes was 85.3% and 88.2% by X-ray analysis and thermal gravity analysis, respectively.

• Journal of Pharmaceutical Investigation
• /
• v.38 no.1
• /
• pp.1-8
• /
• 2008

Planetary ball mill was used to decrease and control the particle size of excipients. The effects of the weight of sample and the revolution number of mill, and grinding time on the particle size of the ground sample were analyzed by response surface methodology. The optimum conditions for the milling of microcrystalline cellulose were 38.82 g of the weight of sample and 259 rpm of the revolution number of mill, and 45 minutes of grinding time. The predicted value of the particle size at the these conditions was $19.02{\mu}m$, of which the experimental value at the similar conditions was $18.68{\mu}m$. The tensile strength of tablets of single-component powders, such as microcrystalline cellulose, hydroxypropylmethyl cellulose and starch, binary mixtures and ground binary mixtures of these powder were measured at various relative densities. It was found that the logarithm of the tensile strength of the tablets was proportional to the relative density. A simple model, based upon Ryshkewitch-Duckworth equation that was originally proposed for porous materials, has been developed in order to predict the relationship between the tensile strength and relative density of ground binary tablets based on the properties of the constituent single-component powders. The validity of the model has been verified with experimental results for ground binary mixtures. It has demonstrated that this model can well predict the tensile strength of ground binary mixtures based upon the properties of single-component powders, such as true density, and the compositions. When the tensile strength of the mixture of microcrystalline cellulose hydroxypropylmethyl cellulose (90:10) and the ground mixture of them were compared, the tensile strength of the ground mixture decreased widely from 45.3 to 5.6% compared to the mixture in case the relative density of tablets was in the range of $0.7{\sim}0.9$. When the tensile strength of the mixture of microcrystalline cellulose starch (80:20) and the ground mixture of them were compared, the tensile strength of the ground mixture decreased widely from 31.0 to 11.6% compared to the mixture in case the relative density of tablets was in the range of $0.7{\sim}0.9$.

• Korean Chemical Engineering Research
• /
• v.54 no.1
• /
• pp.44-51
• /
• 2016

The powder core, conventionally fabricated from iron particles coated with insulator, showed large eddy current loss under high frequency, because of small specific resistance. To overcome the eddy current loss, the increase in the specific resistance of powder cores was needed. In this study, copper oxide coating onto electrically conductive iron particles was performed using a planetary ball mill to increase the specific resistance. Coating factors were optimized by the Response surface methodology. The independent variables were the CuO mass fraction, mill revolution number, coating time, ball size, ball mass and sample mass. The response variable was the specific resistance. The optimization of six factors by the fractional factorial design indicated that CuO mass fraction, mill revolution number, and coating time were the key factors. The levels of these three factors were selected by the three-factors full factorial design and steepest ascent method. The steepest ascent method was used to approach the optimum range for maximum specific resistance. The Box-Behnken design was finally used to analyze the response surfaces of the screened factors for further optimization. The results of the Box-Behnken design showed that the CuO mass fraction and mill revolution number were the main factors affecting the efficiency of coating process. As the CuO mass fraction increased, the specific resistance increased. In contrast, the specific resistance increased with decreasing mill revolution number. The process optimization results revealed a high agreement between the experimental and the predicted data ($Adj-R^2=0.944$). The optimized CuO mass fraction, mill revolution number, and coating time were 0.4, 200 rpm, and 15 min, respectively. The measured value of the specific resistance of the coated pellet under the optimized conditions of the maximum specific resistance was $530k{\Omega}{\cdot}cm$.

• Journal of Life Science
• /
• v.9 no.2
• /
• pp.194-200
• /
• 1999

Grinding aid is a necessary unit operation when the raw materials are handled in solid form, and the purpose is to improve the bioavailability by reducing the particle size. For the particle design of pefloxacin, the dry planetary ball-mill was used. With the drying process, 330 g of zirconia ball with its size of 2 mm in diameter and 10 g of pefloxacin were transferred to the pot and mixed well. The mixture was ground at 112 rpm (60 Hz) for 15, 30, and 60 min, respectively. The most satisfactory grinding products were generated at 15 min of grinding time for their particle size. The volume mean diameter $\X_50$ of the grinding products was 2.97 $\mu$m. X-ray diffraction (XRD), differential scanning calorimeter (DSC), and infrared spectroscopy (IR) patterns were relatively unchanged before pulverizing pefloxacin and in the progress of grinding. Thus, these results suggest that this pulverizing method can be used for grinding products without evident effect on stability of the drug pefloxacin. Dissolution test was carried out to set up the optimal detective condition against residual antibacteria of fish by HPLC. The grinding pefloxacin for 15 min is most effective in dissolution test.

• Resources Recycling
• /
• v.31 no.2
• /
• pp.63-69
• /
• 2022

In this study, mechanical grinding using a planetary ball mill was performed under various conditions to evaluate its effect on the crystal structure of vanadium titanium magnetite (VTM) ore from the Kwain Mine in South Korea. The crystal structure of the activated product was also evaluated. Magnetite and ilmenite were identified as the main types of VTM ore used in the Kwain Mine, and the main types of gangue minerals were iron-based silicate minerals. According to the mechanical activation results, the crystallinity and crystal size decreased as the size of the grinding media (balls) decreased, and the amorphization of the sample/ball filling was significant as the amount of the sample was reduced. In addition, as the grinding speed and time increased, the crystal structure significantly changed, proving that these two parameters had a greater effect on the crystal structure than the ball size and sample/ball filling ratio.

• Resources Recycling
• /
• v.32 no.3
• /
• pp.18-25
• /
• 2023

Sericite was ground with or without additives (LiNO₃ or TiO₂) using a planetary mill. The resultant ground products included the average particle size of 2-3 ㎛ (sericite only or sericite+LiNO₃) and 0.5-0.6 ㎛ (sericite+TiO₂) were obtained within 10 minutes of grinding time. respectively. In the grinding of the sericite without any addictive, the particle size initially decreased, but, as grinding time elapsed thereafter, agglomerates were formed and D50 increased over 10 ㎛. In contrast, when the additive was added, the particle size decreased as the grinding time elapsed and any aggregation was relatively not noticeable, compared with the grinding of the sericite only. As a result of measuring the zeta potential for the raw or the ground samples, variation of the zeta potential values according to pH at the early stage of the grinding with the addictives was gentler than that at the final stage of grinding, which showed the relatively similar trend to the pH-zeta potential correlation in grinding of raw sericite. In addition, as a result of the disintegration experiment through ultrasonic excitation, D50 decreased rapidly only until the disintegration time of about 50 minutes.

• Journal of Powder Materials
• /
• v.21 no.2
• /
• pp.155-164
• /
• 2014