Electrical breakdown of polyethylene using aqueous electrodes

The time for which polyethylene film is able to withstand alternating stresses between 1·6 × 10 5 and 8 × 10 5 V cm -1 has been measured for films of 7·6 × 10 -3 and 1·27 × 10 -2 cm thickness using liquid aqueous electrolyte electrodes, one of which contains iodine of known concentration. The time to failure is found to decrease exponentially with increasing field strength and to be inversely proportional to iodine concentration. Failure due to a corona or a simple thermal mechanism is considered and deemed unsatisfactory as an explanation of the results. The influence of a superimposed direct stress is also examined.