How can medical equipment withstand 4000 volts?

Polyimide film is a new type of organic polymer film with high temperature resistance, which is made of pyromellitic dianhydride (PMDA) and diaminodiphenyl ether (ODA) by polycondensation, salification and imidization in strong solvent dimethylacetamide (DMAC). It is the best film insulation material in the world at present, with excellent mechanical properties, electrical properties, chemical stability, high radiation resistance, high temperature resistance and low temperature resistance (-) 1959, DuPont Company of the United States first synthesized aromatic polyimide, 1962 tried to make polyimide film (PI film), and 1965 began production. At the end of 1960s, China was able to produce polyimide film in small batches, and now it has been widely used in aviation, navigation, spacecraft, rockets and missiles, atomic energy, electronic and electrical industries and other fields.