Monte Carlo simulation of polymer syntheses: a useful tool to judge the REACH and OECD polymer status

The REACH or OECD polymer definition requires a certain chain length, rather than a molecular weight. This makes it very difficult to decide from gel permeation chromatography (GPC) alone whether a substance complies with the REACH polymer definition. Therefore, in parallel to the real in vitro syntheses, we simulated the preparation of polycondensation and polyaddition resins by means of well-known Monte Carlo methods. The output of these simulations (basically a list of all the molecules formed, their molecular weights, and their relative quantities) was used to simulate a GPC. The simulation parameters (reaction types and relative reaction rates) were adapted until a good match between the measured and the simulated GPC was obtained. The simulation was then considered trustworthy. This appeared to be a strong tool to judge if a product is a polymer according to REACH, EPA, or emerging worldwide legislation.