Hindered amine light stabilizers: recent developments

Abstract

In the absence of stabilizers, many polymer systems such as polypropylene have relatively poor UV stability. Other polymers such as polyethylene, styrenics, polyamides and polyurethanes also benefit from UV stabilization. The practical consequences of unchecked exposure to UV radiation are: discoloration, surface crazing (formation of surface microcracks), Embrittlement and loss of mechanical properties (elongation, impact strength, and tensile strength). The effect of UV exposure can be significantly inhibited through proper selection of UV stabilizers. Light stabilizers can be categorized into four general classifications: screening agents, UV absorbers (UVA), UV quenchers, and Hindered Amine Light Stabilizers (HALS).