Rapid determination of oligomeric hindered amine light stabilizers in polymeric materials

Abstract

Hindered amine light stabilizers are essential for the stabilization of synthetic polymers, particularly for materials used for outdoor applications. Although up to now a considerable number of studies dealing with the analytics of this class of stabilizers had been published, especially the determination of oligomeric hindered amine light stabilizers is still an analytical challenge. In the current work, a fast and simple liquid chromatographic method for the quantitative determination of oligomeric hindered amine light stabilizers is presented. A key aspect of this method is their completely different retention behavior depending on the pH, enabling a single peak elution approach by a pH gradient run. This allows a quantitation with simple UV detection independent of the actual oligomeric composition. Calibration curves within the concentration range relevant for the analysis of real polymer samples (LOQ = 70 mg/L) were constructed with R values above 0.99. Spiked extracts from polyolefin samples showed recovery rates between 97.3 and 102.9% for five different commercial hindered amine light stabilizers. Relative standard deviations were between 2.0 and 3.9%. Furthermore, it was demonstrated that the employed approach can be easily adapted for mass spectrometry detection.

Functionality-type and chemical-composition separation for poly(lactide-co-glycolide) using gradient elution with basic and acidic additives in normal-phase liquid chromatography

“…Although the ternary gradient with adding FA could not separate between ester-terminated and acid-terminated PLGA, these results indicated that controlling the protona on of acid groups in polymers plays an important role in changing the reten on behavior of acidterminated PLGA. Therefore we tested if the addi on of a base would increase the de-protona on of the acidic PLGA and increase its reten on [33]. This was tested using a ternary gradient method adding a base (TEA) to EA and adding an acid (FA) to THF (Figure 3(b)).…”

First Evidence of Hindered Amine Light Stabilizers As Abundant, Ubiquitous, Emerging Pollutants in Dust and Air Particles: A New Concern for Human Health

“…Today, HALSs have emerged as the most effective light stabilizers when compared with UV absorbers, which include benzotriazole, benzophenone, and triazine types . The market offers more than 30 HALS structures, encompassing monomeric to oligomeric and polymeric HALSs. , In contrast to traditional monomeric HALSs, oligomeric and polymeric HALSs have been recently developed, offering advantages such as high compatibility with polymers, low mobility, and reduced leaching . The global production of HALSs in 2021 was estimated to exceed 130,000 tons, with China leading as both the largest producer and consumer, accounting for ∼20% of the global production .…”

Enhancement of Ultraviolet Light Resistance of Colorless and Transparent Semi-Alicyclic Polyimide Nanocomposite Films via the Incorporation of Hindered Amine Light Stabilizers for Potential Applications in Flexible Optoelectronics

“…In the current work, another type of light stabilizer, hindered amine light stabilizers (HALS), was attempted to incorporate into the semi-alicyclic CPI films so as to improve the UV stability. Different from the benzotriazole UV absorbers, the HALS photo-stabilizer can achieve the photo-stabilization of the polymers by capturing the free radicals produced during the photo-oxidation and degradation, and decompose the hydrogen peroxide and quenching the excited state energy [ 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ]. This operation mechanism is quite suitable for the photo-stabilization of CPI films according to the photodegradation mechanism of the polymers.…”