Dispersioonpolümerisatsioon

Dispersioonpolümerisatsioon, also known as dispersion polymerization, is a polymerization technique where monomers are polymerized in a continuous liquid phase, often a non-solvent for the growing polymer. The process results in the formation of polymer particles that are stabilized in the continuous phase by steric or electrostatic stabilizers. This method is distinct from suspension polymerization, where larger droplets of monomer are dispersed, and emulsion polymerization, which requires a surfactant and forms much smaller particles.

In dispersion polymerization, the reaction medium is carefully chosen to be a solvent for the monomer but a non-solvent for the polymer. As the polymer chains grow, they become insoluble and precipitate out of the continuous phase, forming discrete particles. Stabilizers are crucial to prevent these particles from coalescing and to control their size and morphology. These stabilizers adsorb onto the particle surface, providing a repulsive barrier. The reaction is typically carried out under agitation to ensure good mixing and uniform particle formation.

The key advantages of dispersion polymerization include the ability to produce polymer particles with controlled size and narrow particle size distribution, often in the micrometer range. The resulting particles are usually spherical and can be easily separated from the reaction medium by filtration. This technique is widely used for synthesizing polymers for applications such as coatings, adhesives, and biomedical materials, and for creating polymer supports for catalysts or chromatographic stationary phases. The choice of monomer, solvent, initiator, and stabilizer dictates the final polymer properties and particle characteristics.