Residual Monomer in Radical vs. Condensation Polymerization Techniques

Posted: February 27, 2007

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In one process, a difunctional acid is reacted with a difunctional alcohol, or for easier reaction conditions, a di-acid chloride and a di-alcohol can be used. For example, a polyester results when polyoxyethylene glycol HO-(CH2CH₂)_xOH is reacted with dodecanedioic acid HOOC-(CH₂)₁₀-COOH. The resulting material is a polyester polymer HO-[(CH₂CH₂)_xOOC-(CH₂)₁₀COO]-.

This type of polymer is neither made with vinyl reactants nor radical processes. It is made using common organic reaction techniques; consequently, the question of residual monomer is not very important, but the removal of byproducts becomes the important issue. Without the removal of byproducts, high molecular weight polymers cannot be obtained.

Polymers are made using different processes and raw materials. It is the selection of these that dictate not only functional properties of the polymer, but also the need for additional analysis including residual monomer content.