University of Wollongong
Browse

Desorption electrospray ionisation mass spectrometry of stabilised polyesters reveals activation of hindered amine light stabilisers

Download (4.16 MB)
journal contribution
posted on 2024-11-16, 07:37 authored by Martin Paine, Ganna Gryn'ova, Michelle L Coote, Philip BarkerPhilip Barker, Stephen Blanksby
The use of hindered amine light stabilizers (HALS) to retard thermo- and photo-degradation of polymers has become increasingly common. Proposed mechanisms of polymer stabilisation involve significant changes to the HALS chemical structure; however, reports of the characterisation of these modified chemical species are limited. To better understand the fate of HALS and determine their in situ modifications, desorption electrospray ionisation mass spectrometry (DESI-MS) was employed to characterise ten commercially available HALS present in polyester-based coil coatings. TINUVIN® 770, 292, 144, 123, 152, and NOR371; HOSTAVIN® 3052, 3055, 3050, and 3058 were separately formulated with a pigmented, thermosetting polyester resin, cured on metal at 262 °C and analysed directly by DESI-MS. High-level ab initio molecular orbital theory calculations were also undertaken to aid the mechanistic interpretation of the results. For HALS containing N-substituted piperidines (i.e., N–CH3, N–C(O)CH3, and N–OR) a secondary piperidine (N–H) analogue was detected in all cases. The formation of these intermediates can be explained either through hydrogen abstraction based mechanisms or direct N–OR homolysis with the former dominant under normal service temperatures (ca. 25–80 °C), and the latter potentially becoming competitive under the high temperatures associated with curing (ca. 230–260 °C).

Funding

Why is ColorbondR steel greener on the other side of the fence? Designing additives to retard weathering of surface coatings

Australian Research Council

Find out more...

ARC Centre of Excellence - Centre for Free Radical Chemistry and Biotechnology

Australian Research Council

Find out more...

History

Citation

Paine, M. R.L., Gryn'ova, G., Coote, M. L., Barker, P. J. & Blanksby, S. J. (2014). Desorption electrospray ionisation mass spectrometry of stabilised polyesters reveals activation of hindered amine light stabilisers. Polymer Degradation and Stability, 99 223-232.

Journal title

Polymer Degradation and Stability

Volume

99

Issue

1

Pagination

223-232

Language

English

RIS ID

87399

Usage metrics

    Categories

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC