repolymerize

Repolymerize is a term used in polymer science to describe the process of forming a polymer again, either from monomer units recovered by depolymerization or from fragments and oligomers that can be reassembled into polymer chains. The concept is central to chemical recycling and closed-loop recycling, where plastics are broken down to recover building blocks and then converted back into polymer material.

In practice, repolymerization may involve condensation-type polycondensation or chain-growth polymerization, depending on the chemistry of the monomers. The process typically requires purification of feedstocks, catalysts or initiators, and control of reaction conditions to achieve desirable molecular weight and polymer properties. By removing byproducts such as water or small molecules, the equilibrium can be driven toward polymer formation. The goal is to produce a polymer with properties close to or suitable for reuse in the target applications.

Applications include recycling of polyesters such as PET, where depolymerization to monomers (or oligomers) is followed by repolymerization; conversely, PLA and other polyesters can undergo depolymerization-repolymerization cycles. Repolymerization can preserve material value and reduce need for virgin monomer, but challenges include impurities, chain scission during previous processing, energy requirements, and controlling molecular weight distribution.