Degradation of cellulosic insulation in power transformers: a SEC-MALLS study of artificially aged transformer papers

作者：Kes Murside; Christensen Bjorn E^*

来源：Cellulose, 2013, 20(4): 2003-2011.

DOI：10.1007/s10570-013-9963-x

• Cellulose
• Viscometry
• Size-exclusion chromatography
• Multi-angle laser light scattering
• Transformer paper
• Ageing

The molecular weight distributions of artificially aged transformer papers were studied using SEC-MALLS with 0.5 % DMAc/LiCl as solvent, providing chain length distributions and averages. The slow dissolution and presence of non-cellulosic contaminants tend in some cases to introduce errors in the DPw estimates, and a modified data processing procedure was developed to correct for extraneous scattering. Data were compared to the intrinsic viscosities obtained in 0.5 M Cuen and the %26apos;viscosimetric DP%26apos; calculated thereof according to ISO 5351. DPvisc was 2-3 times lower than the weight average DP (DPw), but closer to or slightly above the number average DP (DPn) obtained by SEC-MALLS in the case of pure cellulose. Ageing of transformer papers were in some cases associated with changes in the polydispersity (DPw/DPn). The apparent degradation rate (defined as delta(1/DP)/delta t) gradually decreased with time, resulting in a tendency for a %26apos;level-off%26apos; DP in the range 200-300 for DPvisc and DPn, and roughly 1,000 for DPw.

• 出版日期2013-8