Two power capacitors

one passed 1 000 hours aging test according to GB/T 11024.2-2001 and another fresh capacitor unit of same design have been studied in this paper

to analyze the aging influence on the BOPP film morphology and breakdown performance

through the tests of differential scanning calorimetry（DSC）

fourier transform infrared spectroscopy（FTIR）

gel permeation chromatography（GPC）

and small electrode breakdown test. It can be concluded from results that the aging process will cause a small decrease of crystallinity

but there’re no obvious scissions of large molecular chains

or substance produced in the aging process. The breakdown test results show that the aging will cause dielectric strength degradation

especially the original weak area.