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Jusner, P; Bacher, M; Simon, J; Bausch, F; Khaliliyan, H; Schiehser, S; Sumerskii, I; Schwaiger, E; Potthast, A; Rosenau, T.
(2022): Analyzing the effects of thermal stress on insulator papers by solid-state C-13 NMR spectroscopy
CELLULOSE. 2022; 29(2): 1081-1095. FullText FullText_BOKU

Million tons of cellulosic paper have been used for insulating coils in oil-filled electrical power transformers, thereby assuring the electricity supply for our societies. The high working temperatures in transformers constantly degrade paper insulators throughout their service life of up to 40 years. We approached the structural changes in oil-immersed cellulosic paper samples upon thermal stress in a study that compared unbleached softwood Kraft paper used as insulator paper with pure cotton cellulose paper. The model experiments used a thermal treatment in transformer oil at 170 degrees C for up to 14 days. The samples were characterized by means of C-13 CP/MAS NMR spectroscopy, mainly based on deconvolution of the C4 resonance. An automated, fast, and reproducible C4 resonance deconvolution employing the "Peak Analyzer" tool of OriginPro 2020 (OriginLab Corporation, USA) was developed and used to exploit C-13 CP/MAS NMR spectroscopy for the characterization of thermally stressed paper samples. Our results show that thermally induced structural changes depend heavily on the composition of paper, that hornification and coalescence of fibrils take place, and that the allomorph composition of cellulose crystallites is altered under the given conditions.
Authors BOKU Wien:
Bacher Markus
Bausch Florian
Jusner Paul
Khaliliyan Hajar
Potthast Antje
Rosenau Thomas
Schiehser Sonja
Simon Jonas
Sumerskii Ivan

Find related publications in this database (Keywords)
Solid-state structure
Insulator paper
Solid-state C-13 CP/MAS NMR spectroscopy
Thermal stress
Paper aging

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