Thermal Ageing of Cellulose Paper Insulation

Results are presented of investigations into the thermal ageing behavior of cellulose paper insulation in which tests have been carried out between 100C and 160C on well-dried samples of cellulose paper contained in sealed glass vessels in an atmosphere of initially dry nitrogen gas. The degree of ageing has been assessed by measuring the time rate of decrease of several physical and physico-chemical characteristics of the cellulose paper, e.g. burst strength, degree of polymerization etc., and conclusions were drawn concerning their relative sensitivities to the state of ageing of the test sample. In addition to these measurements, the rates of production of the main gaseous decomposition products have also been determined.