RADICAL POLYMERIZATION Meaning and
Definition
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Radical polymerization is a chemical process that involves the creation of polymer chains through the formation of covalent bonds between monomers. Monomers refer to the basic building blocks or small molecules that can react together to form a larger, more complex structure known as a polymer. In radical polymerization, the reaction is initiated by the presence of highly reactive species called radicals.
The process begins with the initiation step, where radicals are generated by the addition of a suitable initiator, such as a peroxide or azo compound, to a monomer. The radicals then react with additional monomer molecules, leading to a chain growth process. The main feature of this type of polymerization is the involvement of free radicals, which have unpaired electrons, making them highly reactive and capable of initiating and propagating polymerization.
As the reactive radicals bond with monomers, the chains continue to grow until the reaction is terminated. The termination step can occur through various mechanisms, such as recombination of two radicals, disproportionation (transfer) of the radical to another growing chain, or reaction with an impurity or inhibitor. The resulting polymer chains can vary in length, branching, and structure, depending on factors like monomer concentration, temperature, and reaction time.
Radical polymerization is widely used in industrial processes for the production of various plastics, elastomers, coatings, adhesives, and other polymeric materials. The ability to control the polymerization conditions allows for the synthesis of polymers with tailored properties, making it an essential technique in the polymer industry.
Etymology of RADICAL POLYMERIZATION
The word "radical" in "radical polymerization" comes from the concept of chemical radicals, which are highly reactive species with unpaired electrons. These radicals can initiate chemical reactions by starting a chain reaction process.
The term "polymerization" is derived from two Greek roots: "poly", meaning many, and "meros", meaning part or unit. Polymerization refers to the process of combining small molecules called monomers to form larger, repeating units called polymers.
Therefore, "radical polymerization" refers to the polymerization process initiated and propagated by radicals. It involves the sequential addition of monomers through a chain reaction mechanism, where radicals continuously react and grow the polymer chain.
