TY - JOUR
T1 - Analyzing the effects of thermal stress on insulator papers by solid-state 13C NMR spectroscopy
AU - Jusner, Paul
AU - Bacher, Markus
AU - Simon, Jonas
AU - Bausch, Florian
AU - Khaliliyan, Hajar
AU - Schiehser, Sonja
AU - Sumerskii, Ivan
AU - Schwaiger, Elisabeth
AU - Potthast, Antje
AU - Rosenau, Thomas
N1 - Funding Information:
Open access funding provided by University of Natural Resources and Life Sciences Vienna (BOKU). The financial support by the Austrian Biorefinery Center Tulln (ABCT) is gratefully acknowledged.
Funding Information:
We would like to thank the University of Natural Resources and Life Sciences (BOKU), Vienna, Mondi Frantschach GmbH, and the Austrian State of Lower Austria for their financial support in the framework of the Austrian Biorefinery Center Tulln (ABCT).
Publisher Copyright:
© 2021, The Author(s).
PY - 2021
Y1 - 2021
N2 - 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 °C for up to 14 days. The samples were characterized by means of 13C 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 13C 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. Graphical abstract: [Figure not available: see fulltext.]
AB - 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 °C for up to 14 days. The samples were characterized by means of 13C 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 13C 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. Graphical abstract: [Figure not available: see fulltext.]
KW - Cellulose
KW - Insulator paper
KW - Paper aging
KW - Solid-state C CP/MAS NMR spectroscopy
KW - Solid-state structure
KW - Thermal stress
UR - http://www.scopus.com/inward/record.url?scp=85120049894&partnerID=8YFLogxK
U2 - 10.1007/s10570-021-04338-z
DO - 10.1007/s10570-021-04338-z
M3 - Article
AN - SCOPUS:85120049894
SN - 0969-0239
VL - 29
JO - Cellulose
JF - Cellulose
ER -