Graft polymerization and other methods to reduce the hygroscopic nature of cellulose insulation

Cellulosic insulation materials are widely used in power transformers and other high voltage devices, but require intensive drying out to remove all moisture. This paper describes three methods used to modify cellulose to reduce its hygroscopicity, of which graft polymerization was the most successful method. The modified paper sheets, however, lost some mechanical strength properties, and showed a tendency to be thicker than the starting material