liitumispolümerisatsioonist

Liitumispolümerisatsioon is a polymerization process where monomer molecules add to one another in such a way that the polymer contains all the atoms of the monomer. This is in contrast to condensation polymerization, where small molecules like water or methanol are eliminated. The process typically involves a chain reaction mechanism, requiring an initiator to start the chain growth.

There are several types of liitumispolümerisatsioon, most notably free radical, cationic, and anionic polymerization. Free radical polymerization is initiated by free radicals, which are species with unpaired electrons. These radicals attack the double bond of the monomer, forming a new radical that can then propagate by adding more monomer units. Cationic polymerization is initiated by carbocations, and anionic polymerization by carbanions. The choice of initiator depends on the nature of the monomer and the desired polymer properties.

Common monomers that undergo liitumispolümerisatsioon include alkenes and their derivatives, such as ethylene, propylene, styrene, and vinyl chloride. These monomers polymerize to form important plastics like polyethylene, polypropylene, polystyrene, and polyvinyl chloride (PVC). The mechanism allows for the formation of high molecular weight polymers relatively quickly. Controlling the reaction conditions, such as temperature, solvent, and initiator concentration, is crucial for managing the molecular weight distribution and tacticity of the resulting polymer.