Interactions of Hindered Amine Stabilizers in Acidic and Alkaline Environments

Abstract

This chapter describes interaction of hindered amine stabilizers in acidic and alkaline environments. Hindered Amine Stabilizers (HAS) are very effective UV-stabilizers that outperform all other types of UV-stabilizers mainly in polyolefins. In addition some HAS are known to offer outstanding long term thermal stability. This high efficiency is based on a radical scavenging mechanism. The chemical reactivity of HAS is needed for their outstanding performance it can cause antagonistic interactions in the presence of other reactive chemicals. These interactions can significantly decrease the UV-performance of HAS. In addition, interactions between HAS and reactive chemicals can also influence the long term thermal stability, processing stability, and discoloration effects of polyolefins. The high alkalinity of some HAS structures is responsible for interactions that can reduce the performance of HAS. Moreover, certain discoloration phenomena appear to be caused by the alkalinity of HAS. Consequently, the selection of the HAS structure should take into consideration the performance under non-ideal, for example, acid exposure conditions and should not only focus on the UV aspect. Finally, the selection must focus on the performance of HAS and the potential risk of premature failure due to HAS deactivation.