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 ( γ c ) and surface tension ( γ 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 γ c values were analyzed by a Zisman plot, a Young-Dupré-Good-Girifalco plot, and a log (1+cos θ) vs log γ L plot. The γ s value of BPDA-BAPE polyimide was evaluated using the geometric mean equation and our multiple regression analysis. The calculated values of γ S d (a dispersion component), γ S p (a polar component), γ S h (a hydrogen bonding component), and γ S were 30.79, 9.32, 0.20, and 40.31 mN·m -1 , respectively. The γ 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.