Electric Volume Resistivity for Biopolyimide Using 4,4′-Diamino-α-truxillic acid and 1,2,3,4-Cyclobutanetetracarboxylic dianhydride

Biopolyimides poly(ATA-CBDA), made from of 4,4 '-diamino-alpha-truxillic acid dimethyl ester (ATA) and 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA), is synthesized and measured its electric volume resistivity at various experimental conditions. The effects of film size, thickness, drying time, and the electric field strength on electric resistivity are investigated and compared with polyimide (Kapton). The electric resistivity for all polyimide and biopolyimide are distributed in the range of 10(15)-10(16) Omega cm, which shows that biopolyimide has high electrical insulation as well as polyimide. The electric resistivity strongly depends on film thickness, which suggests that electric resistivity is a function of electric field strength. The critical electric field for polyimide and biopolyimide films are determined to be 5.8 x 10(7) V/m and 3.2 x 10(7) V/m, respectively. Humidity was found to strongly affect the electric resistivity; similar to 10(16) Omega cm at 34% RH and similar to 10(13) Omega cm at 60% RH for both polyimide and biopolyimide films.