Characterization of the surface properties of β-CD-CA-wood flour polymer by inverse gas chromatography

Poplar wood flour, a low-cost and abundantly available material, was modified by grafting β - cyclodextrin in the presence of citric acid, aiming to expand the application of wood flour. The product was characterized by Fourier transform infrared spectroscopy and the technique of the phenolphthalein probe. By the technique of inverse gas chromatography and the method of Hamieh, the values of surface free energy and nonpolar part of the free energy were obtained. The results demonstrate that the dispersive component of the surface free energy of the products will increase with temperature increases, and the product presents a Lewis basic character with K b / K a  = 3.67. Based on the structure of the product, the basicity comes from two parts. One is the rich electronic environment of the β - CD inner cavity, and the other is the formation of ester bonds through crosslinking between β - CD and wood flour by CA.