Characterization of surface properties of polybutadiene rubber by inverse gas chromatography

Abstract

Inverse gas chromatography was applied to the characterization of the surface properties of polybutadiene rubber (PBR). Four n-alkanes (C6, C7, C8 and C9-alkanes) were chosen as the apolar probes to characterize the dispersive component of surface free energy. Dichloromethane, trichloromethane, acetone, ethyl acetate, diethylether and tetrahydrofuran were chosen as the polar probes to detect the Lewis acid-base parameters. It was found that the dispersive components of surface free energy were 47.07, 46.46, 45.85, 45.60 and 45.09 mJ/m2 at 303, 313, 323, 333 and 343 K, respectively. The results showed that the surface free energy decreased linearly with the increase of temperature. The Lewise acidic number Ka of PBR was 0.34, and the basic number Kb was 1.77. The fact Kb/Ka >1 means that the surface of PBR was amphoteric with dominant basic character and the total ability of the surface to acid-base interactions was 2.11. The free energies of adsorption -deltaG(a)s and -deltaH(a)s by Lewis acid-base interaction were also figured out.