Preparation and Characterization of Surface Energy of BPDA-BAPP Polyimide

The surface properties (water sorption and repellency, adhesion) are closely related to the surface tension of polymer solids. The critical surface tension (gamma(c)) and surface tension (gamma(s)) of a polymer solid were estimated by the contact angle method by our quantitative imaging system. BPDA (3,3',4,4'-biphenyl tetracarboxylic dianhydride)BAPP (1,3-Bis(4-aminophenoxy) propane) polyimide was successfully synthesized. The gamma(s) values were analyzed by a Zisman plot, a Young-Dupre-Good-Girifalco plot, and a log (1+cos theta) vs log gamma(L) plot. The gamma(s) value of BPDA-BATE polyimide was evaluated using the geometric mean equation and our multiple regression analysis. The calculated values of gamma(d)(S) (a dispersion component), gamma(p)(S) (a polar component), gamma(h)(S) (a hydrogen bonding component), and gamma(S) were 30.79, 9.32, 0.20, and 40.31 mN.m(-1), respectively. The gamma(S) of BPDA-BAPP polyimide containing both a methylene group and an ether group was larger than that of the polyimide containing only a methylene group.