Disintegrants particle size

As an alternative to the wet process described above, moulding compositions may be made by mixing a powdered resin or a methylol derivative with other ingredients on a two-roll mill or in an internal mixer. The condensation reaction proceeds during this process and when deemed sufficiently advanced, the composition is sheeted off and disintegrated to the desired particle size. This dry process is not known to be used in any current commercial operation. 

The strong influence of the specific impeller power P/V and of the impeller type on the disintegration of floes can be seen from these curves, so that the effects of the operating conditions and the reactor type can be determined with satisfactory accuracy. The disintegration kinetics are complex, and show an exponential decrease in particle size with time. 

Three different types of furnaces are generally in use for calcination. The shaft furnace is considered to be the most suited for calcining coarse limestone. Furnaces of the rotary kiln type are used for handling materials of mixed particle sizes and lumps which disintegrate during the process. Calcination can be carried out in a fluidized bed-reactor for materials of small and uniform particle size. These furnaces are usually fired with gas, oil or coke in some cases electric heating is resorted to. 

Ordnance propellants are required to give the minimum of muzzle flash, smoke and barrel erosion. All these objectives are assisted by adding to the propellant a proportion of nitroguanidine (picrite), made by treating guanidine nitrate with sulphuric acid and brought to very fine particle size by recrystallisation and disintegration. 

Exposure for7 days resulted in disintegration of many cells, reduced cell density, and reduced carbon fixation particle size distribution altered, and this could affect availability of food for particle-feeding herbivores 3... 

Depending on operation conditions and metal properties, the shapes of the atomized particles may be spheroidal, flaky, acicular, or irregular, but spherical shape is predominant. The spheroidal particles are coarse. For example, roller-atomized Sn particles exhibited a mass median diameter of 220 to 680 pm. The large particle sizes and highly irregular particle shapes suggested that the disintegration process may be arrested either by the premature solidification or by the formation of a thick, viscous oxide layer on the liquid surface. The particle size distributions were found to closely follow a log-normal pattern even for non-uniform particle shapes. 

TABLE 2 Effect of Particle Size and Compression Pressure on Swelling Pressure and Disintegration Time ... 

Shotton, E., and Leonard, G.S., Effect of intragranular and extragranular disintegrating agents on particle size of disintegrated tablets, J. Pharm. Sci., 65 1170-1174 (1976). 

Particle size Flow ability, content uniformity, compressibility, disintegration, dissolution rate... 

---