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Suspension polymerization is divided into two main types, depending on the morphology of the particles that result. In bead polymerization, the polymer is soluble in its monomer and the result is a smooth, translucent bead. In powder polymerization, the polymer is not soluble in its monomer and the resultant bead will be porous and irregular. [5]
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]
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.
The suspension process is practiced by only a few companies because it requires a higher degree of production control and product engineering during the polymerization step. This process suspends the water-based reactant in a hydrocarbon -based solvent.
Polymerization of ethylene oxide is an exothermic process. Overheating or contaminating ethylene oxide with catalysts, such as alkalis or metal oxides, can lead to runaway polymerization, which can end in an explosion after a few hours. Polyethylene oxide, or high-molecular-weight polyethylene glycol, is synthesized by suspension polymerization.
The liquid VF is suspended in water and stabilized either by water-soluble polymers based on cellulose or polyvinyl alcohol. Inorganic salts can also act as stabilizers. The suspension polymerization is usually initiated by organic peroxides (eg diisopropyl peroxydicarbonate), but UV light or ionizing radiation can also be used.
Without proper precautions, autoacceleration of polymerization systems could cause metallurgic failure of the reaction vessel or, worse, explosion. [2] To avoid the occurrence of thermal runaway due to autoacceleration, suspension polymerization techniques are employed to make polymers such as polystyrene.
The polymerization is obtained with a broad molecular weight distribution due to the high viscosity and lack of good heat transfer. very high molecular weights are obtained. Gel effect. For reducing the disadvantages of bulk polymerization, the process can be carried out in a solution. This is known as solution polymerization. [2]