, Volume 17, Issue 2, pp 253–269 | Cite as

Kinetics of the production of chain-end groups and methanol from the depolymerization of cellulose during the ageing of paper/oil systems. Part 2: Thermally-upgraded insulating papers

  • Roland Gilbert
  • Jocelyn Jalbert
  • Steve Duchesne
  • Pierre Tétreault
  • Brigitte Morin
  • Yves Denos


In order to go further in demonstrating that methanol can be used as a universal cellulose degradation indicator in power transformers, the ageing study of standard wood kraft specimens in oil in the range of 60–130 °C (Gilbert et al. in Cellulose 16:327–338, 2009) has been extended to thermally-upgraded (TU) papers. The kinetic model that best tracks the ageing patterns was shown to be a function that can accelerate or decelerate the pseudo-zero kinetics by the adjustment of a free parameter. The results showed a non-negligible contribution of 1,4-β-glycosidic bond breaking in the crystalline regions suggesting that the degradation at this level is not necessary occurring through a quantum mode mechanism. The results also showed a significant error in the determination of the rate constants when obtained from isotherms of varying degree of depolymerization. In the case of TU papers, provided that there is a sufficient amount of stabilizers in the fibrous structure, not only could the self-catalyzing nature of the cellulose ageing process as well as the effect of an external supply of catalysts be lost but the chain-breaking could decrease to nearly zero for an undetermined period well before reaching the levelling-off degree of polymerization. The initial rate constants (k 1o) for the depolymerization and methanol formation of these papers were found to be very near those of standard cellulose (giving about the same activation energy), which indicates that they are obtained from the ageing patterns well before the retardant action has fully taken place. The life extension of TU papers is achieved by a reduction with time of the frequency at which the bonds are ruptured. Moreover, the production of methanol and chain-end groups showed about the same value for the frequency factor, which introduces the possibility that the rate of production of CH3OH from chopped chains is much higher than the rate of depolymerization, so that the latter becomes the rate determining step of the overall reaction. On the other hand, the apparent yield of CH3OH molecules per scission is seen to increase substantially with the amount of stabilizers (from ~0.4 to 0.8 and to 1.4 for a paper containing 0 to 1.15 and to 3.9% (w/w) N2) and to a lesser extent, with the moisture in the specimens. However, these variations could either be attributed to a modification of the CH3OH paper/oil partitioning by the stabilizers and moisture in fibrous structure. Finally, pre-aged systems (130 °C for 168 h) conditioned at 20 °C for variable lengths of time provided further evidence that O2 is not necessarily involved in CH3OH production.


Cellulose ageing 1,4-β-glycosidic bond scission Methanol Depolymerization indicator Kinetics Activation energy Frequency factor Thermally-upgraded insulating paper Moisture content Insulating oil Transformer Remaining life 



The authors sincerely acknowledge P. Gervais, TransÉnergie, Hydro-Québec, for his invaluable support during the project. Special mention is made of the financial support of Électricité de France, without whom the study of the system under nitrogen could not have been investigated. The authors would also like to acknowledge Dr. Helena Håkansson, from the Department of Chemical Engineering, Karlstad University, Sweden, for the preparation of the hydrolyzed samples and the LODP measurements.


  1. Burton PJ, Graham J, Hall AC, Laver JA, Oliver AJ (1984) Recent developments by CEGB to improve the prediction and monitoring of transformer performance, CIGRE Conference Paper 12-09Google Scholar
  2. Calvini P (2005) The influence of leveling-off degree of polymerization on the kinetics of cellulose degradation. Cellulose 12:445–447. doi: 10.1007/s10570-005-2206-z CrossRefGoogle Scholar
  3. Calvini P, Gorassini A (2006) On the rate of paper degradation: lessons from the past. Restaurator 27:275–290CrossRefGoogle Scholar
  4. Calvini P, Gorassini A, Merlani AL (2008) On the kinetics of cellulose degradation: looking beyond the pseudo zero order rate equation. Cellulose 15(2):193–203. doi: 10.1007/s10570-007-9162-8 CrossRefGoogle Scholar
  5. Ding HZ, Wang ZD (2008) On the degradation evolution equations of cellulose. Cellulose 15:205–224. doi: 10.1007/s10570-007-9166-4 CrossRefGoogle Scholar
  6. Ekenstam A (1936) The behavior of cellulose in mineral acid solution: kinetic study of the decomposition of cellulose in acid solutions. Ber Deutschen Chem Geselllschaft 69:553CrossRefGoogle Scholar
  7. Emsley AM, Heywood RJ, Ali M, Eley CM (1997) On the kinetics of degradation of cellulose. Cellulose 4:1–5. doi: 10.1023/A:1018408515574 CrossRefGoogle Scholar
  8. Ford JG (1963) Treated cellulose material and electrical apparatus embodying the same. US Patent 3,102,159, Aug 27Google Scholar
  9. Gilbert R, Jalbert J, Tétreault P, Morin B, Denos Y (2009) Kinetics of the production of chain-end groups and methanol from the depolymerization of cellulose during the ageing of paper/oil systems. Part 1: Standard wood kraft insulation. Cellulose 16:327–338. doi: 10.1007/s10570-008-9261-1 Google Scholar
  10. Håkansson H, Ahlgren P (2005) Acid hydrolysis of some industrial pulps: effect of hydrolysis conditions and raw material. Cellulose 12:177–183. doi: 10.1007/s10570-004-1038-6 CrossRefGoogle Scholar
  11. Jalbert J, Gilbert R, Tétreault P, Morin B, Lessard-Déziel D (2007) Identification of a chemical indicator of the rupture of 1, 4-β-glycosidic bonds of cellulose in an oil-impregnated insulating paper system. Cellulose 14:295–309. doi: 10.1007/s10570-007-9124-1 CrossRefGoogle Scholar
  12. Jasiukaité E, Kunaver M, Strlic M (2009) Cellulose liquefaction in acidified ethylene glycol. Cellulose 16:393–405. doi: 10.1007/s10570-009-9288-y CrossRefGoogle Scholar
  13. Knosp R, Fallah E (1961) Étude du papier imprégné d’huile, Bull. LCIE 30:237L–244LGoogle Scholar
  14. Lundgaard LE, Linhjell D, Hansen W, Anker, MU (2001) Ageing and restoration of transformer windings. Sintef energy research, report TR A5540, EBL-K 43-2001Google Scholar
  15. Lundgaard LE, Hansen W, Linhjell D, Painter TJ (2004) Aging of oil-impregnated paper in power transformers. IEEE Trans Power Deliv 19(1):230–239CrossRefGoogle Scholar
  16. McShane CP, Rapp KJ, Corkran JJ, Gauger, GA, Luksich J (2002) Aging of kraft paper in natural dielectric fluid. In: Proceedings of 14th international conference on dielectric liquids (ICDL). Graz (Austria), July 7–12, pp 173–177Google Scholar
  17. McShane CP, Corkram JL, Rapp KJ, Luksich J (2003) Aging of paper insulation retrofilled with natural ester dielectric fluid. IEEE 2003 annual report conf. on electrical insulation and dielectric phenomena, Albuquerque, USA, pp 124–127Google Scholar
  18. Morrison E (1968) Evaluation of the thermal stability of electrical insulating paper. IEEE Trans Electr Insul EI-3(3):76–82Google Scholar
  19. Prevost TA (2005) Thermally upgraded insulation in transformers. Proceedings of Electrical Insulation Conference and Electrical Manufacturing Expo, Oct. 26, 120-125Google Scholar
  20. Soares S, MPS Ricardo N, Heatley F, Rodrigues E (2001) Low temperature thermal degradation of cellulosic insulating paper in air and transformer oil. Polym Int 50:303–308CrossRefGoogle Scholar
  21. Tamura R, Anetai H, Ishii T, Kawamura T (1981) Diagnostic of ageing deterioration of insulating paper. JIEE Proc Pub A 101:30Google Scholar
  22. Zervos S, Moropoulou A (2005) Cotton cellulose ageing in sealed vessels. Kinetic model of autocatalytic depolymerization. Cellulose 12:485–496. doi: 10.1007/s10570-005-7131-7 CrossRefGoogle Scholar
  23. Zou X, Uesaka T, Gurnagul N (1996) Prediction of paper permanence by accelerated aging I. Kinetic of the aging process. Cellulose 3:243–267. doi: 10.1007/BF02228805 Google Scholar

Copyright information

© Springer Science+Business Media B.V. 2009

Authors and Affiliations

  • Roland Gilbert
    • 1
  • Jocelyn Jalbert
    • 1
  • Steve Duchesne
    • 1
  • Pierre Tétreault
    • 1
  • Brigitte Morin
    • 1
  • Yves Denos
    • 2
  1. 1.Institut de Recherche d’Hydro-Québec (IREQ)VarennesCanada
  2. 2.Électricité de France, R&DClamartFrance

Personalised recommendations