High-shear process

Propellant size reduction by grinding, followed by some type of high-shear process. 

Step 2 Granulate Fluid bed or high shear process and dry to desired moisture ... 

The emulsion-based processes, such as complex coacervation or interfacial polymerization, are best suited for preparing capsules from a few microns to a few hnndred microns. Emnlsification conditions are controlled to produce capsules of varying size. Snrfactants can be introdnced to adjust interfacial tension and further direct the emulsified droplet size. Paddle stirring, rotor-stator mixers, high-pressure homogenization, membrane emnlsifiers, or other high shear processes can all be used to control droplet size. 

Lactone stabilizers are a new class of materials that are reputed to stop the autoxidation process before it starts. These products are derivatives of the benzofu-ranone family. Some blends (Ciba Giegy s HP) claim to be particularly effective in high-temperature and high-shear processing. 

Second, droplets impact and coalesce on the powder bed surface if mixing or wet-in time is slow. Third, droplets spread and penetrate into the moving powder bed to form loose nuclei, again coalescing, if wet-in is slow. In the case of high-shear processes, shear forces break down overwet clumps, also producing nuclei. 

This can cause difficulties in injection moulding and other high shear processing operations. For this reason synthetic cis-poly-isoprene is often easier to mould than the natural polymer. 

Similarly, the ultra-low interfacial tensions and spontaneous solubilization of microemulsion phases can be exploited for the creation of stable and finely dispersed emulsions (7). By quenching the temperature and quickly passing from 2 through 3 or 1 phase mixtures and on down to temperatures in or below the 2 region, small emulsion droplets of oil dispersed in water result without application of high shear processes (5, 8, 81, 94, 95). 

Li Y, Shimizu H (2009) Toward a stretchable, elastic, and electrically conductive nanocomposite morphology and properties of poly[styrene-h-(ethylene-co-butylene)-h-styrenej/multiwalled carbon nanotube composites fabricated by high-shear processing. Macromolecules 42 2587-2593... 

---