Determination of Stablizer Concentrations in Polyethylene.

For many years antioxidants and other additives have been employed to improve the thermoxidative stability of polymers. Because of their low concentration it has been difficult to study the performance of these stabilizers in polymers resins, extruded materials, or aged products. This work describes a new analytical procedure that identifies the type and quantity of each additive in samples of stabilized polyethylene resin. A high field, high resolution NMR method employing a selective signal suppression technique can discriminate between additives with similar molecular structure and provide a quantitative measure of each compound. The method is also suitable for the study of stabilizers in extruded and aged polymer products.