Massapolimerointi

Massapolimerointi, also known as bulk polymerization, is a type of addition polymerization process where the reaction occurs exclusively in the monomer with minimal or no solvent or diluent present. This results in a high concentration of monomer throughout the reaction, which can lead to significant changes in viscosity as the polymer forms.

In mass polymerization, the monomer is typically heated or exposed to an initiator (such as a radical initiator or UV light) to begin the polymerization reaction. As the polymer chains grow, the viscosity of the reaction mixture increases substantially, often becoming a solid mass. This high viscosity can hinder heat transfer and mixing, potentially leading to localized overheating and the formation of polymer with undesirable properties, such as broad molecular weight distribution or branching.

Despite these challenges, mass polymerization is advantageous because it yields a pure polymer product without the need for solvent removal, which can be costly and environmentally problematic. It is often used for producing polymers that are soluble in their own monomer, such as styrene into polystyrene or methyl methacrylate into polymethyl methacrylate. Special techniques or reactor designs may be employed to manage the viscosity increase and heat dissipation, such as continuous stirred-tank reactors or specialized extruders. The purity of the final product makes it suitable for applications where residual solvent is undesirable.