Dispersion polymerization

Dispersion polymerization: Precipitation polymerization in which monomer(s),initiator(s), and colloid stabilizer(s) are dissolved in a solvent forming initiallya homogeneous system that produces polymer and results in the formation ofpolymer particles.Note: The process usually results in polymer particles of colloidal dimensions.

At the onset of polymerization, polymers remain in solution until they reach a critical molecular weight (MW), at which point they precipitate.

These stabilizer molecules are generally graft or block copolymers, and can be preformed or can form in situ during the reaction.

The driving force for the particle separation is steric hindrance between the outward-facing tails of the stabilizer layers.

Toners, instrument calibration standards, chromatography column packing materials, liquid crystal display spacers, and biomedical and biochemical analysis all use these micron-size monodisperse particles, particles which were hard to come by before the development of dispersion polymerization methods.

[5] Because of its unique solvent properties, supercritical CO2 is an ideal medium for dispersion polymerization for many soluble-monomer with insoluble-polymer systems.