|DISPERSION POLYMERIZATION (EMULSION POLYMERIZATION)|
Principle of technology
Dispersion polymerization is a very attractive method owing to the inherent simplicity and scalability of the single-step process. Typically, a precursor solution is dispersed in an immiscible continuous phase by mechanical shearing forces and the help of surface modifiers. The dispersed droplets are then induced to form particles, by crosslinking or polymerization (hardening process) of the precursor liquid. Slow as well as fast hardening processes can lead to good particle quality. However, specific customer needs and specifications often require a completely new design (of the dispersion polymerization process) in order to achieve appropriate product properties.
PreenTec has years of experience using dispersion polymerization procedures for the synthesis of hydrophilic as well as hydrophobic polymers, in water-in-oil and oil-in-water dispersions. Aqueous-aqueous two-phase-systems are used where organic phases have to be avoided. Solvent evaporation methods in combination with dispersion techniques are applied when appropriate. High shearing force stirrers are available for the production of particles in a size range from a few micrometers down to nanometers. Particle fractionation by sieving towers is applied in cases where the customer needs a more narrow particle size distribution.
Materials that can be processed
Alginate: hardened by crosslinking internal gelation with bivalent metal ions
Carrageenan: hardened thermal gelation
Agarose: hardened by thermal gelation
Acrylamide and other acrylic monomers: hardened by radical polymerization
Styrene and other vinylic monomers: hardened by radical polymerization Polyhydroxyalkanoates, poly(lactic acid) and poly(lactic-co-glycolic acid)
Waxes and paraffin: hardened by thermal solidification
Bulk production of slow release material (e.g. anti microbial formulations)
Fluorescent micro- and nano particles for product counterfeit protection
Biodegradable drug carriers
Column packing materials for chromatographic separations