Advances in the determination of hindered amine light stabilizers – A review

• Critical discussion of methods for direct determination of polymers and polymer extracts.
• Comprehensive overview of methods for the characterization and quantitation of monomeric HALS.
• Comprehensive overview of methods for the characterization and quantitation of complex oligomeric HALS.
• Critical discussion on the problems encountered in the determination of oligomeric HALS.
• Comparison of different strategies for determination of HALS with respect to analytical parameters.

Within this paper we discuss analytical strategies for the characterization and quantitation of hindered amine light stabilizers (HALS) an important sub-group of polymer additives. For the determination of monomeric HALS a range of mature and reliable techniques exists, allowing their determination in polymer extracts. If qualitative or semi-quantitative information suffices, certain techniques are capable of sampling directly from the polymer surface with limited or no sample preparation. Different strategies for the determination of complex oligomeric HALS in extracts from polymer samples are discussed. Here, approaches providing only a sum parameter including all HALS oligomers have been distinguished from more sophisticated technologies allowing the determination of single oligomers, their degradation and by-products. Particularly, the latter issue is facing increased interest as it provides important information for polymers aging studies. A tabulated overview provides comprehensive information on different analytical techniques suitable for HALS determination.

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