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Polymerization in which polymer is formed in monomer, or monomer-solvent droplets in a continuous phase that is a nonsolvent for both the monomer and the formed polymer. Note 1: In suspension polymerization, the initiator is located mainly in the monomer phase. Note 2: Monomer or monomer-solvent droplets in suspension polymerization have
In polymer chemistry, emulsion polymerization is a type of radical polymerization that usually starts with an emulsion incorporating water, monomers, and surfactants.The most common type of emulsion polymerization is an oil-in-water emulsion, in which droplets of monomer (the oil) are emulsified (with surfactants) in a continuous phase of water.
Dispersion polymerization can produce nearly monodisperse polymer particles of 0.1–15 micrometers (μm). This is important because it fills the gap between particle size generated by conventional emulsion polymerization (0.006–0.7 μm) in batch process and that of suspension polymerization (50–1000 μm). [4]
An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable) owing to liquid-liquid phase separation.Emulsions are part of a more general class of two-phase systems of matter called colloids.
For example, for the polymerization of ethylene, 93.6 kJ of energy are released per mole of monomer. [8] The manner in which polymerization is conducted is a highly evolved technology. Methods include emulsion polymerization, solution polymerization, suspension polymerization, and precipitation polymerization.
Compared with other heterogeneous polymerization processes (suspension or emulsion) microemulsion polymerization is a more complicated system. Polymerization rate is controlled by monomer partitioning between the phases, particle nucleation, and adsorption and desorption of radicals.
Emulsion polymerization can be done at highly reduced pressures and lower temperatures compared to suspension polymerization. The improved process control and reaction heat removal lead to increase in molecular weight , rate of reaction and yield .
Emulsions are thermodynamically unstable liquid/liquid dispersions that are stabilized. [1] Emulsion dispersion is not about reactor blends for which one polymer is polymerized from its monomer in the presence of the other polymers; emulsion dispersion is a novel method of choice for the preparation of homogeneous blends of thermoplastic and elastomer. [2]