Is My Substance a Polymer?
28 Mar 2025
Understanding Why Polymer Classification Matters
You’ve created a new chemical substance. It’s the greatest thing since sliced bread, and it has potential applications in a number of lucrative fields. However, before you can start to reap the benefits of your creation, you need to be able to legally market it. In many jurisdictions—and the number is growing—you’ll first need to notify or register your new substance with the regulator.
One question you may need to ask is whether your substance is a polymer. While the answer may not matter for practical concerns like ease or cost of manufacture and technical performance of the substance, many jurisdictions treat polymers and non-polymers quite differently. This classification can make a considerable difference to the notification/registration process, both in terms of expense and delays.
The Organisation for Economic Co-operation and Development (OECD) has developed a very clear definition of what is and isn’t a polymer, and this definition has been adopted by many jurisdictions across the globe for regulatory purposes:
Polymer means a substance consisting of molecules characterized by the sequence of one or more types of monomer units and comprising a simple weight majority of molecules containing at least three monomer units which are covalently bound to at least one other monomer unit or other reactant and consist of less than a simple weight majority of molecules of the same molecular weight. Such molecules must be distributed over a range of molecular weights wherein differences in the molecular weight are primarily attributable to differences in the number of monomer units. In the context of this definition a “monomer unit” means the reacted form of a monomer in a polymer.
There’s a lot to unpack in this short blog. To explore polymer classification in depth, download my whitepaper: Is My Substance a Polymer?
With decades of experience in chemical regulatory affairs, Intertek Assuris Chemicals is your trusted partner in navigating the evolving landscape of chemical compliance. Whether you need polymer determination, notification assistance, or risk assessment services, our experts are here to provide tailored solutions that meet your specific needs. Contact us to learn more about how we can help ensure your substances comply with all necessary regulatory requirements or visit our website.
