Bifunctional Silicas with Immobilized Lignin

Silica/lignin biocomposites were obtained by impregnation of the modified pyrogenic silicas with water solutions of polymer. Modification of silica surface was carried out using liquid-phase and gas-phase treatment with alkoxyorganosilanes and hexamethyldisilazane, respectively. The silicas with methyl, amine, and silicon hydride groups in a mono- or bifunctional (methyl-hydride, methyl-amino, amino-hydride) surface layers were impregnated with kraft lignin and characterized using differential scanning calorimetry (DSC), attenuated total reflectance (ATR), Fourier transform infrared (FT-IR), and UV spectroscopies. The influence of nature and amount of silica surface functional groups on physicochemical properties of immobilized lignin has been studied. The data on the structure of the polymer layer and the nature of silica/lignin interactions are discussed.