Mechanical Properties Of Granules Research Articles

Measurements and modeling of CO2 adsorption behaviors on granular zeolite 13X: Impact of temperature and time of calcination on granules properties in granulation process using organic binders

AbstractCO2 adsorption on granulated zeolite 13X by organic binders were studied by volumetric measurements. The goal of research was finding the optimum thermal conditions after shaping by organic binders to enhance the mechanical strength and adsorption capacity of granules. Previously published literature investigated the usage of traditional inorganic binders and the effect of organic binders has never been surveyed. Polyvinyl alcohol and polyethylene glycol were added to zeolite powder as organic binders and the effect of calcination temperature and calcination time on the physicochemical and mechanical properties of granules were studied. The textural/structural and morphological features of synthesized adsorbents were characterized by N2 isotherm, X‐ray diffraction (XRD), Thermogravimetric analysis (TGA), Differential thermal analysis (DTA), Scanning electron microscopy (SEM), and Energy Dispersive X‐ray spectroscopy (EDX). The results showed that using high temperatures and longer periods for the calcination had a favorable effect on their mechanical properties but their effects on the physical properties were negative. Thermodynamic investigations were employed to understand the adsorption behavior. Equilibrium adsorption demonstrated that Langmuir model was the most suitable model for description CO2 adsorption and the maximum adsorption capacity was 4.02 (mmol/g). The thermodynamic analysis indicated that the adsorption process was spontaneous and exothermic in nature. The value of isosteric heat of adsorption was analyzed based on Clausius–Clapeyron equation.

Effect of ball-milling parameters on the rheological properties of mold powder slurry

In this study, mold powder slurries with high solid loading and low viscosity were prepared during the ball-milling process for improving the homogeneity and mechanical properties of granules after spray-drying. The effect of ball-milling parameters, such as solid loading, binder/dispersant content, and ball-milling time, on the flowability, dispersibility, stability, and rheological behavior of mold powder slurries was systematically investigated by rheology observation and sedimentation tests. As these parameters varied, the slurry exhibited the shear-thinning behavior of a non-Newtonian fluid with a shear rate range of 0–50 s−1, which was adequately described by the Herschel-Bulkley model. The optimal parameters that optimized the flowability, dispersibility, and stability of the slurry, along with its rheological behavior, were chosen as follows: solid loading, 60 wt%; modified sodium carboxymethyl cellulose binder content, 1.0 wt%; sodium tripolyphosphate dispersant content, 0.5 wt%; ball-milling time, 60 min.

Comparison of the processing conditions and the properties of granules made from fly ash of lignite and coal

The article presents the results pertaining to granulation of two types of fly ash from (1) coal (hard coal) incineration and (2) lignite (brown coal) combustion. The physical, chemical and mechanical properties of granules were compared to obtain the good quality of aggregates. Three types of binders were added to the ash blends: hydrated lime, Portland cement and phosphogypsum. The experimental technological line was used for pelletizing the fine mixtures; then, the obtained granules were tested immediately after their manufacturing (in fresh state) as well as after curing. The addition of binder improved their mechanical properties. Granulation of powders regimented with strictly defined shares of grains fraction. The axial compression test was conducted to find the best toughness, with consideration of the curing time of granules. Granules in the diameter of 15–18 mm were obtained using a disc granulator. The comparison revealed that the granulation of coal fly ash was more effective because of the processing conditions, and the obtained bodies were characterized by better mechanical properties then those made of the lignite fly ash.

Effect of natural fibres on the mechanical properties of thermoplastic starch

Abstract This paper presents the results covering the mechanical properties of thermoplastic potato starch granules with flax, cellulose fibre, and pine bark addition. A modified single screw extrusion-cooker TS-45 with L/D = 18 and an additional cooling section of the barrel was used as the processing unit. The establishment influence of the fibre addition, as well as the extrusion-cooker screw speed, on the mechanical properties of the thermoplastic starch granules was the main objective of the investigation. The maximum force during compression to 50% of the sample diameter, elastic modulus, and compression strength were evaluated. Significant differences were noted depending on the amount of fibre used, while only an insignificant influence of screw speed on the mechanical properties of the granulate was reported. An increased amount of fibres lowered the maximum force as well as the elastic modulus and compression strength of the thermoplastic starch granulates.

Influence of cyclic moisture loading and unloading on the mechanical properties of alumina oxide granules

The influence of cyclic moisture loading and unloading on the material behavior and the mechanical properties of \(\upgamma \hbox {-Al}_{2}\hbox {O}_{3}\) granules has been extensively studied by uniaxial compression tests. For this purpose, the granules have been treated with two different types of moisture loading and unloading cycles. The first cycle type consists of the moistening of granules in a climate chamber using wet air and complete immersion in a water bath followed by drying in a drying chamber. The second cycle type consists only of the moistening of granules in a climate chamber followed by drying in a drying chamber. During treatment with wet air, the mechanical properties of granules decrease with increasing moisture content. The force–displacement curves flatten and the fracture force, the fracture strength as well as the specific fracture energy significantly decreases. Additional treatment by immersion in a water bath has a further, but, less intense influence on the mechanical properties. On subsequent drying of granules in a drying chamber in order to achieve regeneration, the initial condition can only be partially restored. With increasing number of moisture loading and unloading cycles, a continuous decrease in the strength of granules takes place due to non-regenerative damage of the structure. Furthermore, a significant relationship between granule size and damage could be observed.

Effect of binder to solid ratio on mechanical properties of granules processed using reactive and non-reactive binder

Abstract In wet granulation of powders in high shear granulators, the properties of granules formed can be altered by controlling a number of parameters. One of the crucial parameters responsible for granule properties is the quantity of the binder used for granulation. This can be expressed as binder to solid ratio ( B / S ) or liquid to solid ratio ( L / S ). Researchers have reported in the past the effect of liquid to solid ratio on granulation mechanism and growth, granule structure and consequently on the deformation behavior of the granules. Some researchers have also reported the distribution of the binder and the size distribution of the granules formed as a function of the concentration of the binder used in the process. However, there is limited work reported in the literature on the effect of binder to solid ratio on the physical and mechanical properties of granules. The mechanical properties of the granules can determine the behavior of granules at various stages such as usage, handling, transportation and storage under compression. The work reported in this paper investigates the effect of binder to solid ratio ( B / S ) on the mechanical properties of soft detergent granules made via wet granulation in a high shear mixer. The effect of binder to solid ratio in wet granulation can vary depending upon the nature of the binder used. Hence two different types of binders were used viz. reactive (reacts with base powder) and non-reactive (acts only as a binder) to granulate sodium carbonate as primary particles. The mechanical properties were studied by conducting single and bulk compression measurements. Known models of Heckel and Kawakita and Ludde were also used to predict mechanical properties of the granules. The granulation time required to achieve similar physical properties (particle size distribution and circularity) of the granules decreased with increase in binder to solid ratio. Single granule compression measurements showed that apparent granule strength decreases with increase in binder to solid ratio for both reactive and non-reactive granules which may be due to more liquid binder content in the granules. The Heckel parameter was observed to be approximately 2.5 to 3 times the apparent granule strength obtained from single granule compression measurements for both reactive and non-reactive granules. Packing coefficient increased with increase in binder to solid ratio indicating higher compressibility behavior under similar load for both reactive and non-reactive granules.

The effect of some binding agents on the mechanical properties of granules and their compression characteristics.

Abstract The modulus of elasticity and the crushing strength of cylindrical granules prepared by a template method, and the friability of conventional granules were measured and the effect of the binding agents, PVP, methyl cellulose and maize starch examined. These properties were related to the compression characteristics of the granules and to the crushing force of the subsequent tablets. According to the base material two cases were observed. With dicalcium phosphate little plastic flow was evident and low radial stress transmission was noticed, the softest granules led to the weakest compacts. With paracetamol more plastic flow occurred giving a greater axial to radial conversion of force and the softest granules produced the strongest tablets. The extent of further generated contact area played the major role. Generally, due to the better bonding capacity, dicalcium phosphate gave stronger compacts than paracetamol, although lower radial transmission ratios were recorded. A good conversion of axial to radial force was thus proved not to be the main factor in obtaining good tablets, as was also confirmed by the paracetamol powder alone. With paracetamol the residual pressure on the die wall was greater with the formulations producing satisfactory tablets than with paracetamol alone which gave rise to capping.

Effect of batch size on mechanical properties of granules in high shear granulation

The flow patterns in a high shear granulator depend on the fill volume. For example, DEM simulations reported by Terashita et al. [1] show that fill volume affects the velocities and kinetic energies of the particles. It also influences the granule size distribution [2]. Here the effects on the properties of the granule are described. The total mass of the granulate material was varied without changing the other variables such as impeller speed, granulation time and liquid to solid ratio. The resulting mechanical properties, such as strength, yield stress and Young's modulus, of the granules were measured. For the materials studied in the current work, increasing the fill factor (batch size) increased the values of these material parameters. This could be explained by the relative increase in the number and intensity of collisions between the particles, when the size of a batch was increased, leading to smaller porosities.

Effect of impeller speed on mechanical and dissolution properties of high-shear granules

Impeller speed is one of the most crucial process variables that affect the properties of the granules produced in a high-shear granulator. Several reports can be found in literature that discuss the influence of impeller speed on the granules size. For instance some researchers like Knight report an increase of granule size with impeller speed [1,2], while others (Scheaefer et al. and Ramaker et al.) observed a decrease of granules size with increasing impeller speed [3,4]. However there is limited work reported in literature on the effect of the impeller speed on the mechanical properties of granules. Mechanical properties are important as they affect the performance of the granules on the other downstream process such as transportation and handling. The work reported here serves to address the missing in knowledge gap regarding the influence of impeller speed on mechanical properties granules. How the granulation system responds to the changes in the impeller speeds depends on binder that is used in the process. For this reason the two extreme cases, of a low viscosity binder system and high viscosity binder system are considered in this research. For low viscosity binder system it was observed that the granule size decreased with increasing impeller speed whilst for the high viscosity binder system the opposite was observed by Knight [1]. The granule strength, the Young's modulus and yield strength of the high viscosity granules increased with increasing impeller speed where as the opposite trends were observed for the low viscosity binder granules.

Relationship between mechanical properties and shape descriptors of granules obtained by fluidized bed wet granulation

This paper focuses on two mechanical properties of granules, the coefficient of restitution and the strength, and analyzes their sensitivity to granule geometric parameters. The granules were obtained by fluid bed granulation of glass beads with an aqueous solution of PEG1500. Collisions were arranged between granules, and for granules against two glass plates, the first of them a non-covered plate, whereas the second was a plate covered with a thin film of PEG1500. The coefficient of restitution and the strength were measured for the granules, the former for individual particles also. In the case of individual glass particles the coefficient of restitution was around 0.61 for impacts on the flat glass, and 0.5 on the covered glass; for the granules, this parameter was around 0.44 for both situations and for collisions between granules. Sphericity, lacunarity and fractal dimension of the granule projected area, as well as the granule porosity, were determined. Granules giving the highest values for strength had the largest fractal dimension and the smallest lacunarity values regardless of their sphericity, porosity and coefficient of restitution.

Chitosan as a tablet binder

AbstractChitosan was evaluated as a binder for chlorpheniramine maleate tablets in comparison with other cellulose binders such as sodium carboxymethylcellulose, hydroxypropylmethylcellulose and methylcellulose. The effects of binder concentration on the mechanical properties of granules and tablets as well as on disintegration time and dissolution profiles were studied. Results showed that granules prepared with methylcellulose had lowest percentage of fines and friability. Chitosan tablets showed best dissolution profiles. The rank order correlation for binder efficiency was: hydroxypropylmethylcellulose > chitosan > methylcellulose > sodium carboxymethylcellulose.

EFFECT OF BINDER AND ITS CONCENTRATION ON THE PHYSICAL CHARACTERISTICS OF SULFADIAZINE GRANULES AND TABLETS PREPARED BY WET AND FLUIDIZED-BED GRANULATION METHODS

Sulfadiazine was granulated by the fluidized-bed (Uni-Glatt), as well as by the conventional massing and screening (Wet granulation) methods. The effects of binder concentration and its type on the mechanical properties of granules and their corresponding tablets, as well as on disintegration time and drug content were studied. It was found that the fluidized bed method was an efficient with all tested binders to produce superior granules. However, disintegration time of the corresponding tablets was found to be increased markedly and was greatly affected by the type and the concentration of the binder. Some suggestions to overcome this problem are stated.