Polyadditionsreaktionen

Polyadditionsreaktionen, also known as addition polymerization, are a type of polymerization reaction where monomers add to one another in a way that results in no loss of atoms or small molecules. This process typically involves monomers with double or triple bonds that can open up to form new covalent bonds with adjacent monomers. The resulting polymer chain grows by the sequential addition of monomer units. Unlike condensation polymerization, which releases a small molecule like water or methanol, polyaddition reactions do not produce any byproducts.

Common examples of polyaddition reactions include the polymerization of alkenes to form polyolefins such as polyethylene and polypropylene. In these cases, the pi bond in the alkene monomer breaks, allowing it to join with other monomers to form a long chain. Another significant example is the formation of polyurethanes, which are produced by the reaction between diisocyanates and diols. This reaction also proceeds through addition without the elimination of any small molecules. The molecular weight of the polymer formed is directly related to the number of monomer units incorporated into the chain. These reactions are fundamental in the production of many plastics and synthetic materials.