The Fundamental differences between Addition and Condensation Polymer
Polymers are a group of organic molecules made up of repeating units (monomers). The practice of creating polymers is known as polymerization. Polymerization techniques have advanced so much that today there are two prevalent ways to polymerize organic monomers, namely addition and condensation polymerization.
Addition Polymerization
Addition polymers are synthesized by adding monomers consecutively to form a polymer chain. During this process, the monomer’s double bond opens up, and additional monomers join the chain to form the final polymer. Such a reaction can be initiated by heat, light, or a catalyst.
In an addition polymerization reaction, there are no byproducts generated during the course of the reaction. This means the resulting polymer has no molecular weight limitations. Addition polymerization is commonly used to produce polymers such as polyethylene, polypropylene, and polystyrene.
Condensation Polymerization
Condensation polymers, on the other hand, are synthesized by linking monomers through a chemical reaction that releases certain byproducts. The molecules that are released in this process can either be water, hydrogen chloride, or ammonia, among others. The reaction usually takes place between a molecule with a functional group twice and a molecule with a functional group once, leading to the formation of a bond and the removal of a molecule.
Because of byproduct formation, condensation polymerization requires a stoichiometric balance between monomers for the process to be successful. Therefore, the molecular weight of the resulting polymers is limited.
Examples of condensation polymers include Nylon, Kevlar, and Dacron, which are commonly used in textiles, carpets, and other household items.
Conclusion
In conclusion, the difference between addition and condensation polymers lies in the way they are synthesized. Addition polymerization results in a chain reaction, whereas condensation polymerization involves the removal of a byproduct. Their molecular weight is also different, with condensation polymers offering limited molecular weight. Understanding how these two processes work helps in choosing the appropriate polymers for different applications.
Table difference between addition and condensation polymer
| Addition Polymer | Condensation Polymer | |
|---|---|---|
| Definition | Polymers formed by the addition of monomers without the elimination of any by-products | Polymers formed by the elimination of small molecules as by-products of synthesis |
| Mechanism of Formation | Rapid polymerization reaction occurs between monomers | Slow step-by-step reactoin occurs between bifunctional or trifunctional monomers |
| Molecular Weight | High molecular weight polymers can be easily produced | Low to moderate molecular weight polymers are typically produced |
| Byproducts | No byproducts are formed during polymerization | Small molecules (such as water, amine, or alcohol) are produced as byproducts during polymerization |
| Types | Polyethylene, polypropylene, polyvinyl chloride, polytetrafluoroethylene, etc. | Polyester, polyamide, polycarbonate, etc. |