Difference between polymerization and polycondensation.

Only polymers are obtained from the polymerization reaction. In the course of polycondensation, polymers and low molecular weight substances become the reaction product.


During polymerization sequentially connect both identical and different monomer molecules, building one complex polymer molecule (high molecular weight substance) without isolation and formation of by-products - low molecular weight compounds. Therefore, the output is a polymer with exactly the same elemental composition as the monomer.

In the process of polycondensation, the molecules of one or several monomers, connecting with each other, form a polymer macromolecule and by-product release one or another low molecular weight product (water, alcohol, hydrogen chloride or ammonia). Polycondensation underlies the biosynthesis of cellulose, nucleic acids and, of course, proteins.


These two processes are similar in that at the beginning the initial monomer enters into the reaction. And then, during polymerization in the reaction system, at all stages of the current process, there are increasing active chains, the initial monomer, and the macromolecule that has finished growing. And in the process of polycondensation, the monomer, as a rule, is depleted at the initial stages of the ongoing reaction, and then only polymers (oligomers) interacting with one another remain in the system.

For polymerization and polycondensation, the reactivity of the desired monomers and, of course, their structure are equally important. During polymerization, reactions between the growing molecules usually end in chain termination.

And during polycondensation, the reactions occurring between the growing molecules are the main reactions of the growth of polymer chains. Long chains are formed through the interaction of oligomers. Polymerization proceeds in three stages: initiation, chain growth and chain termination. In this case, the centers of growth of the polymer chain are cations, free radicals or anions. Functionality (the number of reaction centers in a molecule) affects the formation of three-dimensional, branched or linear macromolecules.

Conclusions TheDifference.ru

  1. Polycondensation is characterized by the release of by-products - low-molecular substances such as water or alcohol.
  2. During polymerization, only polymers become the reaction products.
  3. The biosynthesis of cellulose, proteins and nucleic acids is possible due to the polycondensation reaction.