Sterically Hindered Amines and Nitroxyls as Polymer Stabilizers

The principles of the use of sterically hindered amines as polymer and monomer stabilizers have been established by M. V. Neiman et al They studied the chemistry of a new class of compounds, the nitroxyl radicals [1-3]. The possibility of the use of these radicals as stabilizers is based on their recombination reaction with active radicals. Nevertheless, for many reasons, nitroxyl radicals have not been widely used as thermo- and photo-stabilizers. In the course of studies on stabilization by these compounds it has been unexpectedly observed that sterically hindered amines-precursors of nitroxyl radicals-are excellent stabilizers against photodegradation and that their efficiency in this field is much better than that of most of known stabilizers. During the recent years a large number of papers have been dedicated to the synthesis, the application, and the action mechanism of stabilizers. This paper is an attempt to generalize the data in this field.